1. health and fitness
2. dental care

Chairside
®
A Publication of Glidewell Laboratories • Volume 7, Issue 4
Photo Essay
Comprehensive Post and Core
Tooth Repair
Page 22
Digital Communication of Critical
Cosmetic Restorative Guidelines
Dr. Bill Strupp
Page 34
How to Align Teeth in Six Months
Six Month Smiles Founder
Dr. Ryan Swain’s Patient-Friendly
Approach to Orthodontics
Page 59
One-on-One with Dr. John Harden
Hospital Dentistry and Treating the
Medically Compromised Patient
Page 48
Dr. Michael DiTolla’s
Clinical Tips
Page 9
COVER PHOTO
Suzeanne Harms, Video and Trade Show Coordinator
Glidewell Laboratories, Newport Beach, Calif.
Contents
9 Dr. DiTolla’s Clinical Tips
Featured in this issue are two innovative products
we recommend for effectively cleaning and cementing BruxZir® and other zirconium oxide-based crowns.
Also showcased is a new buffering agent designed to
eliminate the sting that can be caused by the acidity of
local anesthetic, and a diamond polishing paste that
will give your porcelain restorations a nice luster.
15 Basic Procedures: An Excerpt from
REALITY Publishing’s “The Techniques,
Vol. 1”
This excerpt from REALITY Publishing’s invaluable reference manual details the numerous tasks in dentistry
that are repeatedly performed and are common to many
specific procedures. Dr. Michael Miller covers a variety
of common tasks, skillfully compiling these basic procedures for easy application in everyday practice.
22 Photo Essay: Post-and-Core Technique
for Endodontically Treated Teeth
Addressing a question I am often asked by fellow
dentists, this photo essay outlines my technique for
placing a post and core in an endodontically treated
tooth using the Rebilda® Post System from VOCO
America. The Dental Advisor recently awarded the
post build-up system its top five-star rating, and after
testing out the kit at our lab, I was also impressed by
its range and simple handling.
34 Digital Communication of Critical
Cosmetic Restorative Guidelines
According to Dr. Bill Strupp, an important element to
consider in a cosmetic restorative case is the horizontal
plane, or HPC. Using a series of case examples, he
demonstrates how the restorative dentist can define
and communicate these critical cosmetic guidelines to
the laboratory and specialists involved in the case to
ensure a successful final result.
Can’t get enough Chairside? Check out our weekly
Chairside Live Web series featuring dental news and
Dr. DiTolla’s Case of the Week — available on YouTube,
iTunes and at www.glidewelldental.com.
Contents
1
Contents
48 One-on-One with Dr. Michael DiTolla:
Interview of Dr. John Harden
This issue’s featured interview is with Dr. John Harden,
a practicing dentist in Atlanta, Ga., who specializes in
hospital-based dentistry for medically compromised
patients. For those interested in this area of the dental
field, this experienced practitioner and dental speaker
has hundreds of stories to share about the many challenges and rewarding experiences that can come from
working in a hospital setting.
59 How to Align Teeth in Six Months:
Six Month Smiles® System Provides
Patient-Focused Approach to Orthodontics
Short-term orthodontics can be an essential offering
and practice builder for restorative dentists, enabling
them to treat potential patients who aren’t interested
in comprehensive orthodontic treatment. In this article, general dentist and founder of Six Months Smiles
Inc. Dr. Ryan Swain discusses his company’s cosmetic
braces system, a patient-focused approach to orthodontics specially designed for general dentists.
64 The Zirconia-Based Porcelain Veneer
Glidewell Publications iPad App
To experience Chairside magazine on
the iPad, search “Glidewell” in the iTunes
Store and download the free Glidewell
Publications app.
2
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In order to adapt to and satisfy patient desires, today’s
practitioners must be versatile and maintain up-todate knowledge of procedures and materials, claims
Dr. Elliot Mechanic. The porcelain-layered zirconia
veneer featured in his case report is just one example
of the type of innovations in dental materials that
are providing us with increasing options for treating
dental patients.
Publisher
Jim Glidewell, CDT
Editor-in-Chief and Clinical Editor
Michael C. DiTolla, DDS, FAGD
Managing Editors
Jim Shuck; Mike Cash, CDT
Creative Director
Rachel Pacillas
Copy Editors
Jennifer Holstein, David Frickman,
Chris Newcomb, Megan Strong
Statistical Editor
Darryl Withrow
Digital Marketing Manager
Kevin Keithley
Graphic Designers
Emily Arata, Jamie Austin,
Deb Evans, Joel Guerra, Audrey Kame,
Phil Nguyen, Kelley Pelton
Web Designers
Jamie Austin, Melanie Solis, Ty Tran
Photographer
Sharon Dowd
Illustrator
Wolfgang Friebauer, MDT
Coordinator and Ad Representative
Teri Arthur
(teri.arthur@glidewelldental.com)
If you have questions, comments or complaints regarding
this issue, we want to hear from you. Please e-mail us at
chairside@glidewelldental.com. Your comments may be
featured in an upcoming issue or on our website:
www.chairsidemagazine.com.
© 2012 Glidewell Laboratories
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Chairside is a registered trademark of Glidewell Laboratories.
Editor’s Letter
One of the reasons why I love Dr. Bill Strupp is his attention
to detail when it comes to dentistry. Some might even call it
obsessive. If you have been to his courses or subscribe to his
newsletter “Crown & Bridge UPDATE,” you will know what
I am talking about. This attention to detail allows Bill to
tackle large cases that might otherwise be less predictable. I
prefer to help dentists focus on the basic stuff — 1 or 2 units
of crown & bridge with a 4 percent remake rate and that
fall into place the other 96 percent of the time. So when it
comes to teaching the big cases, I leave that to Bill because
that’s where his attention to detail can help avoid some huge
snafus. In this issue of Chairside, he shares with us how he
goes about communicating the horizontal plane of the case
to the lab and the other specialists who may be involved.
I used to do a lot of traditional orthodontics on kids and
adolescents, with a few difficult adults thrown in the mix.
And it was too bad, because the adults really did want
to have straighter teeth, but many were not willing to go
through two years of traditional ortho. I found clear plastic
aligner trays to be frustrating because once you have moved
a tooth with an archwire and a bracket, moving a tooth
with an aligner seemed more like wrestling a greased pig.
Dr. Ryan Swain has managed to merge moving teeth using
traditional bonded brackets with an accelerated six-month
time frame that is much more acceptable to most adults. His
article may make you think twice before treating every arch
with alignment issues strictly as a veneer case.
Also in this issue, Dr. John Harden shares with us the
unpredictability of doing dentistry in the OR. I think
showing up to work and having no idea what procedure I
will be doing might drive me crazy, but John thrives on it!
Dr. Michael Miller has also once again generously let me
delve into REALITY Publishing’s “The Techniques,” a book
that I think should be given to all graduating dental students.
Dr. Elliot Mechanic contributes an article on zirconia-based
porcelain veneers that you will want to read as well.
Finally, as we continue to improve the translucency and
esthetics of BruxZir® restorations here at the lab, it is our
hope that one day soon I will have a BruxZir veneer case to
share with you. Keep an eye out for this in a future issue.
Yours in quality dentistry,
Dr. Michael C. DiTolla
Editor-in-Chief, Clinical Editor
mditolla@glidewelldental.com
Chairside® Magazine is a registered trademark of Glidewell Laboratories.
Editor’s Letter
3
Letters to the Editor
just to be safe. It’s a simple step that
seems well worth the effort.
– Mike
Dear Dr. DiTolla,
We received several questions from our
readers about the video “Updated BruxZir
Cleaning, Cementing & Bonding Protocol,”
available at www.glidewelldental.com:
I saw your video on using Ivoclean™ to
clean zirconia crowns. You didn’t mention a
RelyX™ resin cement (3M ESPE; St. Paul,
Minn.) as a good cement for BruxZir®
crowns. 3M reports that this phosphoric
acid/methacrylate cement is good for just
about everything. Have you had problems
with people using it? I always get nervous
about trying new bonding agents/cements/
resins, but I have just started using it. 3M
seems proud of it, and so far, I have not had
any problems with it. Do you have any recommendations for that particular cement?
– Colin Lentz, DDS
Dacula, Ga.
Dear Colin,
I was watching your video on bonding
zirconia crowns, and you mentioned
sandblasting with 50-micron aluminum
oxide to decontaminate them. As many
of us have microetchers with 50-micron
aluminum oxide, is this as good as using
Ivoclean™ (Ivoclar Vivadent; Amherst, N.Y.)
for bond strength, or should we still use
the Ivoclean?
The new RelyX Ultimate Adhesive
Resin Cement from 3M ESPE, when
used in combination with their Scotchbond™ Universal Adhesive (which contains the phosphate monomer MDP),
should work just fine for cementing
BruxZir crowns. The bigger point,
however, is to make sure you use
Ivoclean after trying zirconia-based
crowns in the mouth, to eliminate
the salivary phosphates and give the
Scotchbond Universal Adhesive something to bond to. I haven’t personally
used it because I am so happy with the
handling characteristics of Ceramir®
Crown & Bridge luting cement (Doxa
Dental; Newport Beach, Calif.), but I
would stick with the RelyX if you are
having good results with it.
Dear Gary,
In the research I was referring to, sandblasting was still found to be inferior
to using Ivoclean, even under the bestcase scenario with the sandblasting
pressure set at 2.5 bar. That approach
is still too iffy for me, so I continue
to use Ivoclean after trying crowns in
intraorally. At first I only used it on
zirconia crowns being placed on short
clinical preps, and then one day I
started using it on all zirconia and IPS
e.max® crowns (Ivoclar Vivadent) —
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– Christopher Capehart, DDS
Lewisville, Texas
Dear Christopher,
Dear Dr. DiTolla,
– Gary L. France, DDS
La Mesa, Calif.
ever bond my BruxZir crowns; I almost
exclusively cement them with 3M ESPE’s
RelyX™ RMGI luting cement, just because
of its ease of use and cleanup. With that
being said, I always cement them like I do
my PFMs, and I was under the impression that was OK. If your techniques in this
video will help retention, then I will change
my technique, especially if crowns are
overtapered. Ivoclean™ (Ivoclar Vivadent;
Amherst, N.Y.), Z-PRIME™ Plus (Bisco
Inc.; Schaumburg, Ill.), then RelyX Luting
Plus — would that help retention? Since
RelyX has glass ionomers in it also, I didn’t
know whether using a resin primer would
help or hurt the situation. Please advise. I
love the BruxZir crowns, and I just want to
make sure I am cementing them the best
that I can.
– Mike
Dear Dr. DiTolla,
I just watched your technique video on cementing/bonding BruxZir® crowns. I hardly
I have cemented nearly all of my
BruxZir crowns with RelyX Luting
Plus and have had only one come
off — a very short crown on a lower
second molar. You can still use RelyX
to cement your BruxZir crowns and
be fine. I have started supplementing
it with the Ivoclean after we try the
crown in the mouth, and I now use
Ceramir® Crown & Bridge luting cement from Doxa Dental, since it bonds
to the zirconia material itself. It seems
like an easy enough step to implement, and I know it will increase the
bond of my RMGI to the crown itself.
I also hit the prep with some G5™ AllPurpose Desensitizer (CLINICIAN’S
CHOICE; New Milford, Conn.) to try
to kill most of the bacteria that ends
up on the tooth during temp and tryin. So, my preferred method is now:
Ivoclean and Ceramir in the crown,
and G5 (or GLUMA® Desensitizer
[Heraeus Kulzer; South Bend, Ind.]) on
the prep. Honestly, if you continue to
do what you are doing, you shouldn’t
have any problems. You could go
to my method just on shorter preps,
or use Ivoclean/Z-PRIME Plus/RelyX
Luting cement.
Slow down! Be in the moment! You can’t
take your money with you! Be a good human
being and the money you need will come.
– Mike
– Carol Dudley, dental assistant for 25 years
Greenville, N.C.
Dr. Ellis Neiburger’s article, “Speed Dentistry:
Fast Is Better — Up to a Point,” which was
featured in the Summer 2012 issue of Chairside (Vol. 7, Issue 3), also elicited a flurry of
reader responses:
Response from Dr. Neiburger:
Dear Dr. DiTolla,
I enjoy Chairside, and I wanted to write you
about the poor ethics I feel Dr. Neiburger
has. I would not ever care to begin
reading another article by him. I would be
embarrassed to ever have a patient read
this. I would not ever want him to treat me
(or any of my patients). This article detracts
from your lab, which I am enjoying.
Sorry, I just needed to let you know my
thoughts. So different a philosophy I admire,
like Dr. Pankey’s, where you make money,
enjoy and get to know your patients, and
can be proud of what you do.
Sincerely,
– Ed Olsen, DDS
Hardwick, Vt.
Dear Dr. DiTolla,
Just received the latest issue and must
BARK about the speed dentistry article.
I don’t know any patients that like to feel
rushed in the chair. Most patients want some
conversation and for the staff to “kiss them”
first before sticking them and grinding on
them. I think Dr. Speed is more interested in
making tons of money as opposed to treating a real human being. How can you treat
a patient you don’t know? Quit talking so
much?! How impersonal. Get rid of difficult
patients?! How do you advertise for “good
patients” only? Rapid injections? OW!
I feel dentistry is becoming way too
impersonal — nobody has time or MAKES
time to get to know anyone anymore.
It’s a great pleasure to respond to
Dr. Olsen and dental assistant Dudley
and their misunderstandings about
speed dentistry. Most of the negative
comments I receive come from professionals who are troubled by new ideas
or wish to keep the status quo, no
matter what the economic or health
improvements could be for the patients and staff.
Speed dentistry is a way of looking at
the delivery of dentistry to the patient.
The faster you do invasive treatments,
while maintaining quality, the better
off the patient will be. Rather than
dehumanize dental treatment, speed
dentistry can reduce actual and
psychological suffering. It reduces the
trauma and abuse inherent in some
dental treatments (e.g., extractions).
It can also provide more time for the
important socialization, treatment dis­
cussions and just plain visiting that
is so necessary to maintain a close
personal connection with each patient
and ensure future visits, referrals and
cariogenic, fattening snacks around
the holidays. It fits all practices since
the practitioner decides how it is
implemented and to what degree.
Because it requires a bit more planning
and energy (working faster and more
efficiently), speed dentistry is not for
the lazy.
Dr. Olsen and Ms. Dudley are focusing
on the possibility of using speed
dentistry to increase income at the
expense of rushing patients through;
but in reality, speed dentistry gives the
practitioner and the patient more time
since treatment time is shortened,
leaving more relaxed time available to
all. That is what one would call “being
a good human being.” If you doubt
this explanation, ask your patients
what they would prefer: a five-minute
or a 25-minute extraction? A 15-minute
or a one-hour root canal? A sevenminute or a 30-minute prophy? It
all can be done faster and better (and
you don’t have to buy a kit or take
the course).
– E.J. Neiburger, DDS
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Contributors
Michael C. DiTolla, DDS, FAGD
Dr. Michael DiTolla is a graduate of the University of the Pacific Arthur A. Dugoni School of Dentistry.
As Director of Clinical Education and Research at Glidewell Laboratories in Newport Beach, Calif.,
he performs clinical testing on new products in conjunction with the company’s R&D department.
Glidewell dental technicians have the privilege of rotating through Dr. DiTolla’s operatory and
experiencing his commitment to excellence through his prepping and placement of their restorations.
He is a CR evaluator and lectures nationwide on both restorative and cosmetic dentistry. Dr. DiTolla has
several clinical programs available on DVD through Glidewell Laboratories. For more information on
Dr. DiTolla’s articles or to receive a free copy of his clinical presentations, call 888-303-4221 or e-mail
mditolla@glidewelldental.com.
John W. Harden Jr., DMD
Dr. John Harden received his Doctor of Dental Medicine from the Medical College of Georgia School of Dentistry in 1978, and has been in private practice in Atlanta since that time. In 1985, Dr. Harden completed
a residency training program in anesthesiology at the Illinois Masonic Medical Center in Chicago. He has
been on the medical staff at Emory University Hospital Midtown since 1988, where he regularly receives
referrals for the fearful and medically compromised patient. A member of the ADA, Georgia Dental Association and the Northern District Dental Society, he also serves on the board of directors and is past president
of the Emile T. Fisher Foundation for Dental Education in Georgia. Contact him at jhdmd@bellsouth.net
or visit www.jhdmd.com.
Elliot Mechanic, BSc, DDS
Dr. Elliot Mechanic has been practicing general and esthetic dentistry in Montreal, Quebec, since 1979.
Dr. Mechanic serves as an Oral Health editorial board member for esthetics, and is a member of numerous
professional organizations, including the International Academy for Dental-Facial Esthetics, Academy of
Laser Dentistry and the AACD. Dr. Mechanic takes great pride in his work, which has afforded him the
pleasure to work with executives, professionals, celebrities, international stars and everyone in between.
He can be reached at info@drmechanic.com.
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Michael B. Miller, DDS
Dr. Michael Miller is the co-founder, president and editor-in-chief of REALITY, and he maintains a dental
practice in Houston, Texas. He is a Fellow of the Academy of General Dentistry, as well as a founding and
accredited member and Fellow of the American Academy of Cosmetic Dentistry, for which he created its
acclaimed accreditation program. Dr. Miller has contributed to several texts and authors regular columns
for General Dentistry, the peer-reviewed journal of the AGD. He is also a founding board member of the
National Children’s Oral Health Foundation. He can be reached at mm@realityesthetics.com.
William C. Strupp Jr., DDS, FAACD
Dr. Bill Strupp is a practicing dentist best known for his vast knowledge of comprehensive cosmetic and
restorative dentistry. He lectures nationally and internationally to thousands of dentists each year, and has
been published in many prominent dental publications. Dr. Strupp also publishes the newsletter “Crown &
Bridge UPDATE,” which is aimed at educating practitioners in better dentistry. An AACD Accredited Fellow,
Dr. Strupp continually evaluates and applies clinically relevant research to the day-to-day practice of
crown & bridge dentistry. His teachings center on his 43 years in private practice, from which he’s been
regarded as “the dentist’s dentist.” Contact him at 800-235-2515, via e-mail at bill@strupp.com or by visiting www.strupp.com.
Ryan B. Swain, DMD
A graduate of the University of Florida College of Dentistry, Dr. Ryan Swain is a general dentist and the
CEO and founder of Six Month Smiles Inc. He trains dentists internationally in short-term orthodontics,
and is constantly working to make orthodontics more accessible for general dentists. Dr. Swain practices in Scottsville, N.Y., where he focuses exclusively on short-term orthodontics with the Six Month Smiles
System and other forms of conservative cosmetic dentistry. Contact him at ryan@sixmonthsmiles.com or
www.sixmonthsmiles.com.
Contributors
7
9
Number of
consecutive years
Glidewell Laboratories
has won the Dentaltown
Townie Choice Award in the
“Veneer & High Esthetic”
laboratory category
70%
Percentage drop in precious
metal-based restorations
prescribed by dentists from
Glidewell Laboratories in
2012 vs. 2007
47.2%
Percentage of adults in the U.S.
who have periodontal disease
Source: The America Academy of Periodontology, www.perio.org
8
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$31,000
Numbers
by the
Price
paid
by the
highest
bidder, a
Canadian
dentist,
for the
molar of
Beatles
icon John
Lennon
at a 2011
auction
201,523
Total number of implant restorations fabricated
by Glidewell Laboratories through August 2012
1,612
Number of dental labs in
the U.S. that use Glidewell
Laboratories to fabricate
their temporaries
Dr. DiTolla’s
CLINICAL TIPS
PRODUCT........ Ceramir® Crown & Bridge
SOURCE........... Doxa Dental Inc. (Newport Beach, Calif.)
855-369-2872, www.ceramirus.com
With BruxZir® restorations steadily growing in popularity,
I continue to look for better ways to work with this unique
material. Ceramir Crown & Bridge luting cement from
Doxa Dental is the only permanent cement that contains
phosphates, making it the only cement that will bond to
the internal aspect of a BruxZir crown without the use of
a zirconia primer. Regardless of your chosen technique,
we still recommend using Ivoclean® after intraoral try-in.
(For more on this universal cleaning paste from Ivoclar
Vivadent, see the Clinical Tip on page 10.)
Ceramir is hydrophilic while placing the crown and
moisture-tolerant while setting, so there is no need to dry
the tooth bone-dry; in fact, it is preferable to leave the
tooth moist. There is even no need to air-dry the prep, as
any pooled moisture can simply be removed with a few
cotton pellets. Once the crown is in place, any residual
moisture will not affect the cement, even if saliva comes
in contact with it while it is setting. Ceramir also has a
nice rubbery stage during the set time to help avoid any
interproximal “boulders” and to allow for any excess
cement to be peeled off in one piece.
Dr. DiTolla’s Clinical Tips
9
Dr. DiTolla’s
CLINICAL TIPS
PRODUCT........ Ivoclean®
SOURCE........... Ivoclar Vivadent Inc. (Amherst, N.Y.)
800-533-6825, www.ivoclarvivadent.us
When I started looking into the best way to cement or
bond BruxZir® crowns, I stumbled across some research
done by Ivoclar Vivadent that showed that zirconia oxide
gets contaminated once it is tried in the mouth and comes
in contact with saliva. It turns out that the phospholipids
in saliva contain the same phosphate groups as zirconia
primers. Furthermore, simply rinsing the saliva out of
the crown does not remove the phosphate groups that
are bonded to the zirconia oxide, and using phosphoric
acid only worsens the problem because it is full of
phosphates as well. To effectively remove these phosphate
groups, a zirconia oxide solution needs to be used to
clean the crown. Ivoclean is the only product like this
available today.
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Once the salivary phosphate has bonded to the zirconia
oxide in the crown, Ivoclean works by flooding the inside
of the crown with a greater concentration of zirconia oxide.
Placing Ivoclean into the crown creates a concentration
gradient, so that the phosphates that were bonded to the
crown become bonded to the zirconia oxide in the Ivoclean.
After 20 seconds, the Ivoclean is simply rinsed away,
creating a fresh bonding surface on the inside of the crown
for the zirconia primer. To watch an in-depth presentation
on this topic, visit the Video Gallery section of the
Glidewell Laboratories website (www.glidewelldental.com)
and view the “Updated BruxZir Cleaning, Cementing &
Bonding Protocol” video.
Dr. DiTolla’s
CLINICAL TIPS
PRODUCT........ Onpharma® Anesthetic Buffering System
SOURCE........... Onpharma Inc. (Los Gatos, Calif.)
877-336-6738, www.onpharma.com
After spending countless hours experimenting with the
best way to give a painless injection, I got decently good
at it; however, no matter how much topical anesthetic I
used to keep patients from feeling the needle, they always
felt the sting of the acidic local anesthetic (pH 3.9) as it
went into the tissue. I know you can give Citanest® Plain
(DENTSPLY Pharmaceutical; York, Pa.) — which has
a neutral pH of 7.4 — as an initial injection, and then
follow it with some Cook-Waite Marcaine® (Carestream
Health Inc.; Atlanta, Ga.) to avoid the sting, but that
doesn’t seem practical for infiltrations, for example. I also
believe in efficiency, so I love the STA device because I
can anesthetize a single mandibular molar, set down the
syringe and start prepping.
When Dr. Mic Falkel from Onpharma called me to tell me
about his anesthetic buffering system that he said would
allow me to inject any anesthetic at a neutral pH to avoid
the sting, I was ready to order it. But I was really sold when
he mentioned that buffering the anesthetic created 2,500
times more of the active form of the anesthetic than when
it was at its original pH of 3.9. Rather than having to wait
the typical eight to 10 minutes for the body to convert the
anesthetic to the active form on a lower block, injecting
the buffered anesthetic will let you know if your block is
working within a minute or two.
Dr. DiTolla’s Clinical Tips
11
Dr. DiTolla’s
CLINICAL TIPS
PRODUCT........ Rapid-Glaze Diamond Polishing Paste
SOURCE........... Yates-Motloid Inc. (Chicago, Ill.)
800-860-0473, www.yates-motloid.com
Dentists often ask me about the best way to adjust and
polish restorations. While protocols differ slightly for
different materials, they all have a few things in common.
Adjustments should be made with the finest grit diamond
you have available. A coarse diamond will leave scratches
that are almost impossible to remove, and even a medium
grit bur can be challenging. Every polishing cup or wheel
in the set should be used, and all visible scratches should
be gone by the time you are finished using the last cup
or wheel. That’s about all you need to do in the posterior.
In the anterior, the high shine should be restored on any
facial surfaces that were adjusted. In fact, I will often use
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Rapid-Glaze on a bristle brush at a slow speed on the facial
surfaces of crowns even when I haven’t adjusted them.
This is usually because some cement has stuck to the
facial of the crown or veneer, or because the surface just
doesn’t look shiny enough after using the last polishing
cup or wheel. Whatever your technique, a final pass with
Rapid-Glaze will add a nice luster to your restorations.
BasiC
Procedures
An Excerpt from REALITY Publishing’s “The Techniques, Vol. 1”
T
– ARTICLE by
Michael B. Miller, DDS
here are numerous tasks in dentistry that are
repeatedly performed and are common to many
specific procedures. We have detailed these
tasks in this article. The tasks are listed in roughly
the order in which you would encounter them as you
progress through a procedure.
Basic Procedures
15
Mark Occlusion Before Preparation
(Figs. 1, 2)
This should actually be done at the exam appointment to
determine whether the occlusal contact areas of a tooth
fall on enamel or on an existing or planned restoration. By
knowing the location of these contacts, you will be better
able to advise your patient on the best restoration. For
example, if you are restoring a mandibular second molar,
a tooth which presumably is most susceptible to wear, and
the centric stop is squarely on the restorative material,
you would want to inform the patient that a material with
superior wear resistance would be a prudent choice. In
addition, if the tooth has an abfraction lesion, removing
eccentric contacts could prevent the lesion from enlarging
and may relieve dislodging forces from a subsequently
placed restoration.
Figure 3: Defective restorations are present on the maxillary left central incisor, left lateral incisor and left canine.
Figure 1: Occlusion is marked on mandibular second premolar, displaying
a centric stop on enamel. Replacing the defective amalgam can be done
confidently with composite because main occlusal contact is on enamel.
Figure 4: Defective restorations have been removed and replaced
prior to preparing teeth for crowns. The new restorations will be
reliable foundations for the crowns.
Figure 2: Occlusion is marked, showing no obvious deflective contacts
on the maxillary second premolar. An abfraction lesion could be safely
restored without worrying that occlusal forces could lead to its loss
of retention.
Figure 5: Definitive crowns have been cemented on preparations that
were rebuilt with reliably bonded foundations.
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Check Existing Restorations Before
Preparation (Figs. 3–5)
If there are existing restorations in teeth destined for
full coverage, they should be carefully checked and
replaced if there is any doubt at all as to their adequacy
to serve as build-ups. A good rule of thumb is: If you
did not recently (within two to three years) place the
restorations yourself, they should be replaced now.
This can be done prior to beginning the actual crown
preparation or be delayed until the gross preparation
is finished.
Caution: The thinness of a Tofflemire-like band,
which makes it easier to place through a tight contact,
can actually be a disadvantage, since it is not difficult to
cut through the band with a sharp carbide bur or diamond.
Using a thin band may give you a false sense of confidence.
If you repeatedly “nick” it during the preparation, you can
still damage the adjacent tooth. You can also penetrate
through a Tofflemire-like matrix with air abrasion. Therefore,
if you can get a thicker protective device such as InterGuard
through the contact, it would be a safer alternative.
!
The shade of composite used to replace faulty restor­
ations is not critical, but should be in the same general
shade range as the teeth, assuming the definitive
restoration will be fabricated without metal support.
This is especially true when the definitive restoration
is fabricated from a relatively translucent ceramic or
resin material.
On the other hand, when a metal-based restoration
is planned, using a build-up material that contrasts
with tooth structure can be advantageous, since this
contrast helps you see the transition from build-up to
tooth and, therefore, ensures that the margin of the
restoration will be prepared on tooth structure and not
build-up material.
Protect Adjacent Teeth During
Preparation (Figs. 6, 7)
Iatrogenic damage to adjacent teeth is widespread.
A study, which we reviewed in REALITY NOW #106,
found that 78 percent of 71 Class II cavities resulted
in adjacent tooth surfaces being scarred as a result of
the preparation. With small preparations, the risk of
scarring the adjacent tooth increases.
Figure 6: Tofflemire-like bands have been placed on mesial and distal to
protect adjacent teeth from the high-speed diamond used to prepare onlay. As proximal contacts have not been opened, scarring the adjacent
teeth would be difficult to prevent without the bands. The full bands were
“sawed” through the very tight contacts and then the excess was cut off
with scissors.
While specific products such as InterGuard® (Ultradent
Products Inc.; South Jordan, Utah) have been developed
to prevent this type of damage, a simple (and
inexpensive) Tofflemire-like band can also be used.
And, because a Tofflemire-like band is relatively long
and thin, it can also be “sawed” through a tight contact.
To use a Tofflemire-like band, you would typically need
to cut off the excess once it is in place, so it does not
interfere with the procedure.
However, cutting a band once it is already in place can
leave sharp edges and corners. If you are using a rubber
dam, this sharpness will probably not be a problem,
although it can tear your gloves. But without the dam, it
can lacerate a tongue and/or cheek. Therefore, be sure
to round the cut corners.
Figure 7: InterGuard has been inserted to protect the second premolar
during the tunnel preparation through the mesial surface of the first molar.
Basic Procedures
17
Figure 8: Caries-detecting dye is applied to the
lesion as soon as it is uncovered.
Figure 9: Caries-detecting dye remains in the
lesion for no more than 10 seconds.
Figure 10: Caries-detecting dye has been
rinsed and slightly stains the carious lesion on
the axial wall.
Figure 11: Carious tooth structure as indicated
by the dye has been removed and proximal surface has been opened.
Figure 12: Caries-detecting dye is applied
again to the lesion.
Figure 13: Second application of cariesdetecting dye has been rinsed. No stains
are visible.
Apply Caries-Detecting Dye and Remove
Carious Lesion (Figs. 8–14)
Even though their efficacy has been seriously challenged,
68 percent of the REALITY Editorial Team still uses a
product in this category at least some of the time. If you
do use one of these products, apply for 10 seconds and
rinse. Any stained tooth structure is then removed with the
least destructive instruments, typically slow-speed burs and
spoon excavators. Reapply the dye and repeat the removal
of any stained tooth structure until the dye no longer stains
the tooth. Discretion needs to be used, however. If you are
getting close to the pulp and the dentin is still staining, you
should stop removing any additional tooth structure.
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Figure 14: Caries-detecting dye has been applied and rinsed,
revealing stained carious tooth structure. Darker dyes are sometimes
preferred to the original red color for more contrast, especially as the
lesion approaches the pulp.
Pulp Protection (Figs. 15, 16)
With a properly sealed restoration, pulp protection
is not necessary. However, you need to guard against
mechanical trauma to the pulp. If there is no exposure,
you can proceed with the rest of the procedure, being
careful not to put pressure on thin dentin over the pulp.
To protect against mechanical trauma, place a small
amount of a flowable material (composite, compomer
or resin ionomer) over the pulp. With mechanical
exposures, achieving hemostasis is the most important
aspect. Once hemostasis is accomplished, you can
proceed with the rest of the adhesive procedures.
Using a sterile cotton pellet that has been dipped
in 5% sodium hypochlorite (Clorox, but check the
concentration on the bottle) and then blotted to make
it damp, apply pressure for 20–60 seconds, depending
on the size of the exposure. Gentle rinsing with sterile
saline and hemostasis should follow. Then proceed with
adhesive procedures, again using a flowable material to
prevent mechanical trauma to the pulp.
Figure 15: Defective amalgam has been removed, exposing the pulp.
Sodium hypochlorite was used for hemostasis.
With a carious exposure, no suppuration should be
present. If there is suppuration, endodontic treatment
is inevitable. Otherwise, slight bleeding is probably
advantageous because it may help remove some of
the bacterial invasion of the pulp. In fact, if a carious
exposure does not bleed, it may be advantageous
to induce slight hemorrhaging to remove some of
the bacterial invasion. Then proceed with the same
procedure as described for mechanical exposures.
In a recent REALITY Editorial Team survey, 88 percent
of the members stated that they have bonded over
exposed pulps. It was also estimated by these editorial
team members that this treatment failed in about
18 percent of the teeth. Therefore, we strongly advise
that you inform your patients that, while this treatment
has an estimated success rate of about 82 percent, they
still may require endodontics.
Figure 16: After etching and adhesive application, flowable composite
(ÆLITEFLO™ [Bisco Inc.; Schaumburg, Ill.]) has been placed to protect the
pulp from mechanical trauma. As an alternative, a resin ionomer can be
placed over the exposure after achieving hemostasis, but before applying
the etchant and adhesive or self-etching adhesive. The advantage of placing resin ionomer before other procedures is to preserve the hemostasis
you have achieved. After the resin ionomer is placed and light-cured, you
can proceed as if there never was an exposure.
With mechanical exposures, achieving
hemostasis is the most important aspect.
Once hemostasis is accomplished, you
can proceed with the rest of the
adhesive procedures.
Basic Procedures
19
Figure 17: DO preparation has been completed on mandibular second premolar, giving direct access to the mesial of the first molar. Even though the
first molar will no doubt require a restoration in the near future due to the
fracture lines and internal discoloration (suggesting carious involvement), it
is prudent to note whether the mesial surface has obvious signs of decay.
Without visible carious involvement, the subsequently placed new restoration for the first molar can be planned to leave the mesial surface intact.
Figure 18: Carious lesion found on mesial surface of maxillary first molar
during the preparation of the second premolar.
Figure 19: Adjacent tooth surface is cleaned with an interproximal scaler
that will remove external stains and deposits, but will not remove tooth
structure. Contact remains intact. By cleaning the adjacent tooth surface,
you can validate that it is noncarious and the new restoration can contact
clean tooth structure.
Figure 20: Amalgam on mesial of mandibular first molar protrudes into DO
preparation in second premolar.
Figure 21: Coarse finishing disc (Sof-Lex™ XT [3M ESPE; St. Paul, Minn.])
is used to recontour amalgam. This is followed by finer grits of the same
disc system for polishing.
Figure 22: Contouring is completed. The restored distal surface of the
premolar can now be properly contoured, without the limitations of trying
to conform to the poor contour of the amal­gam restoration.
Check Adjacent Teeth After Preparation
However, when the contact is not broken, you may not
have access to completely smooth an adjacent restoration.
In this instance, a finishing strip (aluminum oxide or diamond) would be used instead of a bur or disc. A perforated
strip (interproximal scaler) may also be used to clean
proximal surfaces of hard adherents prior to placing the
restoration. CM
(Figs. 17–22)
Be sure to check the adjacent tooth surface for possible
caries or to smooth existing restorations. If proximal caries
exists in the adjacent tooth, this is the optimal time to restore
it. At this point, you have direct access to the carious lesion,
allowing the most conservative preparation possible. If the
adjacent tooth has a rough, overcontoured or overhung
restoration, it should be smoothed and/or recontoured with
finishing discs or finishing burs, if access permits.
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Dr. Michael Miller is the co-founder, president and editor-in-chief of REALITY. He
maintains a dental practice in Houston, Texas. Contact him at mm@realityesthetics.
com.
Reprinted by permission of REALITY Publishing Company. © 2003 REALITY
Publishing Co. Vol. 1, The Techniques, pp. 11–14.
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Photo Essay
Post-and-Core Technique for
Endodontically Treated Teeth
– ARTICLE by Michael C. DiTolla, DDS, FAGD
lacing post and cores is not an
everyday procedure for most
den­
tists, yet I get a surprising number of e-mails from dentists
asking which post-and-core system I
prefer. Rather than limit myself to one
system, I like to try out the various systems in the lab’s operatory. For the
case that follows, I used the Rebilda®
Post System (VOCO America Inc.;
Briarcliff Manor, N.Y.) to restore an
endodontically treated tooth #10 with
severe decay. In addition to radiopaque, translucent fiberglass posts
and corresponding burs, the system
includes a dual-purpose cement/
core build-up material and dualcured, self-etch bonding agent. I was
pleasantly surprised by the system’s
completeness and ease of use.
Post-and-Core Technique for Endodontically Treated Teeth
23
Figure 1: After reviewing the radiograph to assess the condition of the
endodontic treatment and the condition of the canal, we can begin
removal of the gutta percha. My goal is to extend the post two-thirds of
the way into the root, while leaving a minimum of 4 mm of gutta percha
in the apical third of the tooth. Although the gutta percha in this tooth is
short of the radiographic apex, there is no apparent pathology and the
patient is asymptomatic, so I am comfortable placing a post.
Figure 2: We begin the process of removing
the gutta percha using the 0.7 mm reamer.
The safe-end tip on the reamer and the use of minimal vertical
pressure helps to prevent ditching or perforating the walls of the canal.
Tilting your head can help to visualize the faciolingual orientation of
the reamer.
Figure 3: Take a look from the facial as well to ensure that the angulation
of the reamer is along the long axis in a mesiodistal orientation. Glance
again at the radiograph to help you picture where the reamer should be
going. Seeing pieces of gutta percha jumping out of the coronal portion
of the root is a good sign. Position the reamer into the gutta percha along
the path of least resistance.
Figure 4: As the reamer progresses into the canal, place an endo stopper
on the reamer if you haven’t already. When the reamer begins to bottom
out, hitting tooth structure and the gutta percha in the apical third of the
root, it is time to stop and take a radiograph to verify your position.
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Figure 5: This is one of those times when digital radiography really comes
in handy, making you more efficient than if you were to run a film through
a developer. I can see on the radiograph that the reamer has indeed
begun to engage the tooth structure and is right at my desired depth of
two-thirds the length of the canal. I take the reamer out of the canal and
measure the length. The goal is to have two-thirds of the post in the root
and one-third of the post in the build-up.
Figure 7: Next, we move up to the 1.5 mm
Rebilda Post drill, the middle size of the three
post burs supplied in the kit. It seems to fit many maxillary lateral
incisors and is fluted to remove a significant amount of gutta percha.
Progressing apically, I feel it stop 1.5 mm short as it bottoms out in the
tooth. Resist the urge to shove it down the last bit of the way to match the
length of the reamer — that’s how roots get fractured!
Figure 6: It is now time to replace the
reamer with the first Rebilda Post drill. The
goal here is to remove more of the coronal gutta percha
to create the post space without removing too much structure internally
in the apical third of the root. All of the root fractures I have seen in the
past 20 years have originated in the apical third of the root at the base
of the post. I have always attributed these fractures to over-preparation.
I am using the 1.2 mm Rebilda Post drill, which goes to the same depth
as the reamer.
All of the root fractures
I have seen in the past
20 years have originated in
the apical third of the root
at the base of the post.
I have always attributed these
fractures to over-preparation.
Post-and-Core Technique for Endodontically Treated Teeth
25
Figure 8: A glance into the coronal portion of the root reveals that the
coronal gutta percha has been removed completely. Residual gutta percha
in the coronal portion of the root can make it difficult to seat the post
correctly. If you have difficulty removing it, you can move up to the largest
drill, the 2.0 mm Rebilda Post drill, but take care to advance it slowly until
it just begins to bind in the canal and no further. All of the drilling you are
seeing here was done at 2,000 rpm with my KaVo ELECTROtorque plus
handpiece (KaVo Dental; Charlotte, N.C.).
Figure 9: The fiber posts in the Rebilda Post System kit are color coded
to match the drills, so I use a 1.5 mm post to match the size of the last
drill we took to length. Mark the post at that length to verify that it is
seating completely when you try it in the tooth. It’s OK if there is some
side-to-side movement of the post; in fact, I prefer a passive fit to ensure
we are not setting up stress in the brittle, endodontically treated root.
Figure 10: Using a permanent marker, I make a length mark on the post
slightly longer than I think I will need. I like to have the top part of the post
be close to the surface of the build-up material I am going to add, so that
when I am light curing from the incisal I can be sure that the light is going
down the fiber post and into the canal and the surrounding cement. The
literature shows that a fiber post that flexes when the tooth does causes
fewer problems than an inflexible post.
Figure 11: I prefer to cut the post to size outside the patient’s mouth
to avoid having the cut portion drop into the back of the mouth. Also, I
prefer to do the cutting now, instead of while the post is in the tooth and
the cement is setting, so that the vibration from the handpiece doesn’t
break the cement bonds to the tooth structure and the post. As I am
intentionally going with a passive fit of the post, I am counting on my
cement bond to hold the post and core in place.
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Figure 12: Holding the Rebilda Post with an articulating paper holder, I
coat the post with alcohol to remove any contamination that might be
present from inserting it into the canal. All posts are shipped in non-sterile
packaging, so some dentists will coat them with alcohol prior to trying
them in for the first time. There is certainly nothing wrong with doing that.
Figure 13: Next, I evaporate the alcohol using my A-dec Warm Air Tooth
Dryer (A-dec Inc.; Newberg, Ore.). This might be the most obscure
instrument in dentistry, and it’s certainly one of the tougher ones to find
(most of your supply reps have probably never even heard of it). Without
the dryer, which uses a venturi to remove any moisture from the air, I
would have a lot less confidence in my bonding procedures. I use it
on a hose that has never had a handpiece on it and is therefore free of
oil, since the presence of oil can cause even more bonding issues than
moisture contamination.
Figure 14: Here I am using a microbrush to
coat the fiber post with the enclosed Ceramic
Bond. Because there is some glass in this fiber-reinforced
composite post, this silane does a great job of bonding the resin cement
to the post. After coating the post and waiting 60 seconds, I will use the
A-dec Warm Air Tooth Dryer to thin and evaporate the Ceramic Bond on
the post prior to placement. At this point, you can flush the canal with
sodium hypochlorite to make sure all gutta percha and dentinal debris
have been removed.
Figure 15: Futurabond DC, a dual-cured,
self-etching bonding agent reinforced with
nano particles, is the bonding agent included with this system.
VOCO’s clever unidose dispensing system ensures that you always have
fresh material because the two components aren’t mixed until you push
down on one side of the blister pack, causing the self-etching bonding
agent to mix with the dual-cure activator. Here you can see me squeezing
the pack to mix the liquids.
Post-and-Core Technique for Endodontically Treated Teeth
27
Figure 16: After activating the Futurabond DC, simply punch through the
foil pack with the enclosed microbrush, which is specially designed for
placing bonding agents inside the canal. The long, tapered brush extends
nearly all of the way into the prepared post space. I find it easier to puncture the foil surface with the handle side of the microbrush and then insert
the elongated tip into the foil reservoir as shown. This helps prevent the
microbrush from bending.
Figure 17: Once the tapered post brush is coated with Futurabond DC, I
pump it up and down in the canal space for about 20 seconds. I have my
operatory light turned off because we definitely do not want to cure the
bonding agent in the canal at this point. If we were to do that or if it were
to pool in the apical third of the canal, it would be impossible to get the
post to seat properly.
Figure 18: Again I use the A-dec Warm Air Tooth Dryer to evaporate
the solvents from the Futurabond DC in the canal. You can see why
introducing moisture or oil from a regular three-way syringe at this point
in the bonding process could be especially problematic. A simple test is
to take your air-water syringe and blow it for 20 seconds on the face of
your wristwatch to make sure it is free of oil and moisture.
Figure 19: I have found that the best way to remove excess bonding
agent from the apical third of the post space is not with air, but with a
typical endodontic paper point. Place the paper point as far as it will go
into the post space and then give it a few seconds to absorb any excess
bonding agent. Observe the tip of the paper point when removed to see
if it appears wet and then continue inserting points until one appears dry
after removal.
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Figure 20: You can now start the core build-up. The Rebilda DC dualcure core build-up material is an automixing system dispensed directly
into the post space using the enclosed microtip, as shown here. These
tips are the thinnest I have seen for an automix system. In fact, at first
glance it’s hard to believe the build-up material is going to be able to pass
through the opening, but, of course, it does.
Figure 21: When filling up the post space, take care not to fill it completely. If you fill the post space completely and then try to jam the post down
into place, the shape of the canal and a fundamental rule of hydraulics
won’t allow this to happen. If you just were to fill up the apical half of the
post space you would be fine, since by the time the post is inserted you
would have excess build-up material flowing out the coronal aspect. In
the rare instance when you might not use enough material, it is very easy
to fill a void by placing additional material with the enclosed microtip.
Figure 22: If you happen to correctly estimate the amount of build-up
material to place in the canal, you should see something like this. The tip
of the post should be at the same length you measured it, indicating that
it is properly seated. You shouldn’t see a mass of extra build-up material
on the exterior of the tooth, although cleanup with the microtip is easy
if needed.
Figure 23: I prefer to cure the post, Futurabond DC and Rebilda DC
simultaneously before placing the coronal build-up. Otherwise, I would
be curing through a huge ball of composite and, in my mind, the success
of this post and core comes down to how well everything cures inside the
canal. Curing it as you see here gives me the best opportunity to get light
down the post and deep into the canal. I cure for 40 seconds.
Post-and-Core Technique for Endodontically Treated Teeth
29
Figure 24: In the past I have done free-form
composite build-ups, which I call the softserve ice cream technique because you swirl on material,
swirl on more material and then cure. However, I always find myself
coming back to shaping aids, both in the interest of speed and because I
have a harder time getting an ideal prep shape with the soft-serve method
than if I slightly overbuild it with a shaping aid and cut it back. Here I am
using the Rebilda Form.
I always find myself coming
back to shaping aids, both in
the interest of speed and
because I have a harder time
getting an ideal prep shape with
the soft-serve method than if
I slightly overbuild it with a
shaping aid and cut it back.
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Figure 25: I cut the Rebilda Form to an acceptable height and shape the
gingival aspect to allow room for the papilla. I then stabilize the Rebilda
Form with my index finger, while I fill the form with a fresh mix of Rebilda
DC. I am using the endo tip again, but any tip would work here. You may
notice that I am using the same material I used to bond the post for the
build-up, ensuring compatibility at the interface and reducing inventory.
Figure 26: I set the curing light on top of the Rebilda Form and cure
away, aiming for a 40-second cure. Sometimes I cure for 40 seconds and
then hand the light to my assistant so she can cure it for an additional
40 seconds. Maybe it’s because I graduated from dental school in the late
1980s, but I really don’t trust most manufacturer-suggested curing times.
Until a study comes out proving that overcuring is bad, I plan to stick to
this technique.
Figure 27: After my marathon cure, I stick an explorer into the Rebilda
Form, slide it up to the occlusal and remove the shaping aid. Oops! Look
at the void I created in the build-up. I may have been pressing a little too
hard with my index finger because the vertical void looks a lot like the tip
of the explorer. Apparently, I neglected to continue to inject as I removed
the tip from the Rebilda Form. This falls squarely under the heading of
operator error.
Figure 28: Fortunately, the oxygen-inhibited layer is still present on the
Rebilda DC, so all I need to do to fix these voids is to put a new tip on
the build-up syringe and add material as I am doing here. This will also
give me a chance to light cure again, especially from the gingival, where I
wasn’t able to cure when the Rebilda Form was in place.
Figure 29: With the voids filled, I now have my preferred build-up shape,
which is roughly the outline of an overbuilt lateral incisor. As I mentioned
earlier, I find it much simpler to achieve an ideal lateral incisor prep
through a subtractive process than through an additive process using the
soft-serve technique.
Figure 30: I do not have the full contour of a lateral incisor in this case,
so I can’t do my typical Reverse Preparation Technique on this tooth.
Because I can’t use the round bur I usually start with, I begin with this
super coarse 856-025 bur (Axis Dental; Coppell, Texas). I will start doing
my axial reduction with this bur, but first I need to make sure I get rid of
any flash at the gingival margin. I like to get my #00 cord (Ultrapak® Cord
[Ultradent Products Inc.; South Jordan, Utah]) in the sulcus as soon as
possible, but the flash first needs to be eliminated if we are going to have
any chance of getting the cord smoothly into place.
Post-and-Core Technique for Endodontically Treated Teeth
31
Figure 31: The #00 cord is placed into the sulcus with the two ends flush.
This will retract the gingival margin about 0.5 mm, which will allow us to
drop the margin to this new gingival level. When the #00 cord is removed,
the net effect will be a 0.5 mm subgingival margin without having to take
a bur subgingival or cause bleeding.
Figure 32: Usually there is a fair amount of time between when I place
the bottom #00 cord and the top #2E cord (Ultradent Products Inc.), but
in this case the prep is almost finished after using only the 856-025 bur.
This top #2E cord will provide the lateral retraction of the tissue and make
room for the impression material, while the bottom cord provides the
vertical retraction that allows us to prep our virtual subgingival margin.
Figure 33: One of the benefits of using an electric handpiece is the ability
to turn it down to 2,000 rpm with the water off to see precisely what
you are doing, preferably through loupes. Trace a line along the gingival
margin to make sure it is crisp and clear. Remember, the handpiece is
only spinning at 2,000 rpm, so there is not enough heat generated to
damage the pulp.
Figure 34: With the top cord in place, the subgingival margin is just
barely visible above the gingival margin. This top cord stays in place for
8 to 10 minutes. When it is removed, there typically will be no bleeding
since the bottom #00 cord is still in contact with the inflamed base of
the sulcus. Once the top cord is removed, an impression of the finished
post-and-core preparation can be taken. CM
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digital
Communication
of Critical Cosmetic Restorative Guidelines
O
ne of the most important elements of a cosmetic
restorative case is the horizontal plane of the case
(HPC). The HPC is defined as the plane that the
incisal edges of the anterior restorations should follow
relative to specific landmarks of the face. Ninety percent
of the time, the plane can follow the pupillary line plane.
The gingival plane of the anterior teeth should parallel the
HPC when the gingival line is visible in the smile. Facial
asymmetry and biological limitations based on anatomy
dictate the reality of what is possible when matching the
gingival plane to the chosen HPC.
Leaving the HPC up to chance or ignoring it often compromises the cosmetic outcome of the case. As such, it is
important for the restorative dentist to define and then communicate the HPC to the laboratory and to the specialists
involved in the interdisciplinary treatment of the case. When
biological limitations do not exist, it is important for the
laboratory and the specialists to follow the designated plane.
Analyzing and deciding on the appropriate HPC is easily
done using a lip-retracted, full-face digital photograph imported into presentation software such as Apple Keynote®
(Apple Inc.; Cupertino, Calif.) or Microsoft PowerPoint®
(Microsoft Corporation; Redmond, Wash.). In this author’s
opinion, Keynote is by far the easiest program to use.
– ARTICLE by
William C. Strupp Jr., DDS
1
Figure 1: The retracted view full-face photograph is made with the patient
standing against a wall marked with “correct” horizontal and vertical lines.
The patient must not lean against the wall and should stand erect without
tilting the head. The photographer should attempt to eliminate any camera
tilt and to take care not to shoot the photograph at an angle from the left,
right, above or below. The patient must be “square” to the camera and vice
versa. The photograph is captured and then imported into Apple Keynote.
2
STEPS in the digital
communication process
1. Take the photographs.
2. Analyze the photographs to determine the HPC.
3. C
ommunicate the HPC to the laboratory and
the specialists involved in the interdisciplinary
management of the case.
Figure 2: The first step in analysis is to draw a 0-degree line on the
photograph that extends beyond the spectral highlights — the white dots
in the pupils caused by reflection of the camera flash. Other 0-degree lines
can be drawn over the teeth and the gingiva to assess the horizontal plane
and to determine the HPC. Analysis of these lines reveals the patient’s tilt
and facial asymmetry in the photograph.
Digital Communication of Critical Cosmetic Restorative Guidelines
35
3
4
Figure 3: The photo is then “corrected” by tilting it in Keynote so the
0-degree line crosses both spectral highlights at the same point. It is now
possible to draw other 0-degree lines to decide if the patient or camera
was tilted, or if the patient is tilted anatomically. From these lines the ideal
HPC can be determined. In this case, because the patient’s ear lobe plane
anatomically matches his pupillary line, the selected HPC is the pupillary line.
Figure 4: If the case is to be restored, communication of the HPC is
necessary. This is accomplished by adding the patient’s name, date of the
photograph and selected HPC to the slide. The restorative dentist selects
the HPC for this case as the gingival plane of tooth #6 & #10. This slide
is then printed and sent to the laboratory, as well as to the specialists if
surgical correction is necessary.
Further analysis of the incisal and gingival planes reveal asymmetry. If the
gingival plane does not show in the full smile, that asymmetry does not
require correction. If the incisal plane can be corrected without creating
undue envelope of function issues, and if there is sufficient biological
support available to allow a change, then it is possible in the final
restorative case to change the incisal plane to match the HPC. A complete
understanding of occlusion is necessary to make these determinations.
This maxillary case was previously restored without paying attention to the
foregoing discussion, and the cosmetic result mirrors the lack of attention
to these details.
When a modification of the gingival plane is necessary to match the HPC,
the periodontist decides if there is adequate biological support to create
the desired changes, communicates this to the restorative dentist, and
then matches the gingival plane to the HPC using the appropriate surgical
approach and biological respect.
5a
When the case is mounted for diagnosis and treatment planning or
for treatment, the laboratory trims the base of the maxillary cast to be
parallel to the HPC (the gingival plane of tooth #6 & #10) and mounts
the models with the base of the maxillary cast parallel to the horizontal
plane of the articulator. In addition, the midline of the face should be
the midline of the articulator. All diagnostic waxing, case planning and
finishing of the restorative case is done on models mounted by the
laboratory in this orientation.
5b
Figures 5a, 5b: Many clinicians suggest using a straw bite to record the correct HPC. Unfortunately, 99 percent of these bites are incorrect and lead the
laboratory to mount cases incorrectly. Diagnostic waxing, case planning and finishing using an incorrect HPC is a sure way to compromise the cosmetic
outcome of the case.
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6a
6b
Figures 6a, 6b: Postoperative computer analysis of case photographs reveals both successes and failures, thereby helping the clinician improve communication and cosmetic results for future cases. These are preoperative photos of a missing lower central case planned for phased restorative treatment of all of the
teeth over time. No periodontal surgery was done in this case because the gingival plane was not a cosmetic compromise. The chosen HPC was the gingival
plane of tooth #6 & #11.
7a
7b
Figures 7a, 7b: The “after” photograph reveals the success and failure of the case. The incisal plane is perfectly parallel to the HPC, but the maxillary right
central is 0.3 mm too long. The restorations were made of single-tooth IPS e.max® Press (Ivoclar Vivadent; Amherst, N.Y.) restorations on supragingival
margins. A custom zirconia abutment was used for the missing mandibular central.
8
Figure 8: The short lip exposes the gingival line, and were it not within
normal cosmetic limits, surgery would have been required to alter it so it
would be parallel to the HPC.
9
Figure 9: Keynote also allows the clinician to use innovative concepts in
studying cases and communicating with the laboratory and specialists.
Here, an image of a ruler was cropped and properly sized. The maxillary
left central incisor was exactly 9 mm wide, so this dimension was used to
size the ruler image. (Note: A known dimension must exist in the photo to
properly size the ruler image.) The opacity was reduced to 20 percent, the
image was duplicated and rotated 90 degrees, and then both images were
placed over the maxillary left central to study length and width proportions.
Digital Communication of Critical Cosmetic Restorative Guidelines
37
10
11
Figure 10: If a probe is placed in the same plane as the teeth and photographed in the full-face retracted view, imported overlay images (in that
plane) can be properly sized to analyze length and width proportions.
Knowing the exact width and length of a central incisor is the easiest way
to correctly size imported images.
12a
Figure 11: Calculations can be made to decide length and width proportions
and to determine if those proportions are possible. It is impossible to make
a tooth that is 9.0 mm wide as it emerges from the tissue be less than
9.0 mm wide. The gingival diameter of the root mesiodistally cannot be
altered without drastic surgical procedures. The three dimensions depicted
on this photograph can be assessed for practical application for making the
final case. In this case, 75 percent is ideal, but probably not possible.
12b
Figures 12a, 12b: Another interesting thing that can be done for communication with specialists is to draw circles at the height of the existing gingival line
and then overlay an image of teeth obtained from the Internet, properly sized and reduced in opacity, to evaluate where the gingival levels are and where they
should be placed relative to the circles under the image. It is obvious from the circles in this image that the gingival line is not very esthetic. It is also obvious
from the line drawn along the gingival line of the Internet photo that the gingival line of this image is asymmetrical. The tissue on the right cuspid is receded
and the tissue on the laterals is not receded enough. When the teeth are overlaid matching the incisal edges, which were ideal in length, the gingival aspect
of where the tissue is and where it needs to be can be evaluated and communicated to the specialists.
13
38
Figure 13: The circles can be moved apically into an acceptable position
relative to the HPC using a 0-degree line over the central gingival line
as a reference point. The height of tissue on the cuspids and centrals
should fall on this line, with the laterals 1.0–1.5 mm short of the line.
Once the imported image is overlaid, an analysis of what might be better
cosmetically can be visualized, taking into account the gingival line issues
of the imported photograph. This information can be photographically
transmitted to the periodontist for proper tissue positioning, provided it
is permitted biologically. Likewise, the incisal plane can be visualized and
communicated to the laboratory for proper design in both the diagnostic
and final phases of treatment.
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14a
14b
14c
14d
Figures 14a–14d: Instead of using imported images of teeth, outline drawings of teeth that are properly sized and proportioned can be used to evaluate the gingival and incisal planes. The outline drawing in this photo is exactly 8.5 mm x 11.0 mm, which is believed to be the most realistic size for this
case. Once the outline drawing is properly sized, it is moved over the gingival line of the teeth in the correct HPC and duplicated in Keynote. It is then
flipped in Keynote and the mirror image is properly positioned in the correct HPC to match the other side. Analysis of these line drawings can be helpful
to the referral doctors and to the laboratory technician in managing the case.
The question surgeons must answer is: “Are the desired cosmetic changes possible given the biological support that exists?” The question laboratory
technicians must answer is: “Can the case be properly mounted so the quest for a HPC can be achieved?” The question for the restorative dentist is:
“Will I spend the time to do all this stuff?” If the restorative dentist will not take the time to learn how to do all of these “high-tech” procedures, all is not
lost. Most of the communication needed can be transmitted with the use of a Straight Smile Guide™ (Crown & Bridge UPDATE, 800-235-2515). Created
for technophobe dentists, it is a quick way to analyze and communicate critical cosmetic parameters to the team.
15
Figure 15: The Straight Smile Guide is a stiff plastic sheet with grid lines
running vertically and horizontally. This guide comes in two sizes. The large
size is used to evaluate the HPC by placing it over a full-face, retracted
view, 8.5-by-11-inch photograph of the patient. The small size is for the lab
technician to aid in mounting the case in the correct HPC and then to verify
that the mounting is correct.
Digital Communication of Critical Cosmetic Restorative Guidelines
39
16
17
Figure 16: Using the Straight Smile Guide, decide on the correct HPC.
Do this at the diagnosis and treatment planning stage, before beginning
treatment. Move the guide around on the photograph to decide on the
correct horizontal plane of the case. Record the anatomical points to be
used for the HPC.
18
Figure 17: Provide the lab with the full-face retracted photo and the
Straight Smile Guide (large one is used over the photo, small one is used
for the articulator to assist in mounting and to verify accuracy). Information
on the anatomical points that should be used for the correct HPC is also
given to the laboratory for proper mounting. In this case, it is the gingival
plane of tooth #6 & #10.
19
Figure 18: The lab uses the properly trimmed maxillary cast to properly
mount the case. If the midline of the face is also marked on the model, the
mark can be used to position the cast in the articulator just like the teeth
are positioned in the mouth. Using the small Straight Smile Guide aids in
proper mounting and verifies that the mounting is correct to the HPC.
Figure 19: The lines across the top model show the base trimmed
improperly — it is not parallel to the gingival plane of tooth #6 & #10,
which is the chosen HPC. The lines across the bottom model show
the base trimmed properly — it is parallel to the gingival plane of tooth
#6 & #10, which is the chosen HPC. Mounting the base of the maxillary
cast in the same horizontal plane of the articulator gives the technician
making the case the correct HPC relationships (cast to articulator to
patient). This minimizes the issue of uphill and downhill smiles.
Most of the communication needed can be transmitted with the use of a
Straight Smile Guide. Created for technophobe dentists, it is a quick way
to analyze and communicate critical cosmetic parameters to the team.
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20a
20b
20c
20d
Figures 20a–20d: These four images were printed from Keynote and sent to the periodontist with an e-mail describing the cosmetic concerns with the HPC.
This was a post-orthodontic case where the roots were 50 percent burned off on the maxillary central and lateral incisors. In addition, there was an anterior
open bite from second bicuspid to second bicuspid. Occlusion on the molars was flat due to no anterior guidance and excessive wear patterns. The case
was planned to restore all of the upper and lower teeth with partial-coverage porcelain to establish appropriate occlusion on the teeth capable of carrying
the load.
The patient’s chief complaint was her gummy smile and lack of occlusal contact. The horizontal lines are all at 0 degrees. The lines drawn on the central
represent an ideal proportion if the incisal edges were and were not lengthened. Altered passive eruption (APE) meant no supporting bone would need to
be removed to treat the APE.
21
Figure 21: This photo reveals the issue with the HPC. The angulation of
1 degree should be corrected surgically before restorative care is provided.
The APE on the right side requires correction, while on the left it does
not. The lip asymmetry on the right displays more gingiva. In addition, the
incisal plane of the cuspids parallels the gingival asymmetry; it is off by
1 degree. The simple correction for this case is to remove tissue from the
right side and lengthen the incisal edges on the left to create a restorative
case that is parallel to the HPC. Note that the red lines are at 0 degrees and
the white lines are at 1 degree. The final gingival and incisal planes should
parallel the red lines. Soft tissue and bone would need to be removed over
the right bicuspids to avoid an excessive step from anterior to posterior.
Digital Communication of Critical Cosmetic Restorative Guidelines
41
22a
22b
Figures 22a, 22b: A technique that can be used to “standardize” the size of photographs is to draw a line between the spectral highlights, duplicate the
line and then cut and paste it onto another photo. Resizing the second photograph until the line fits exactly in the same spots on the spectral highlights
makes both photographs the same size, provided camera angle does not play a role. This enables the user to measure the length of the teeth before and
after surgery to see the treatment results.
23
24
Figure 23: In order to have a harmonious HPC, the tissue will need to be
decreased on the right and the incisal length will need to be increased
on the left. Note that the 0-degree line is in red and the 1-degree line is
in white.
25
26
Figure 25: Periodontal surgery was done to “correct” the APE on the six
anterior teeth and bone was removed to create a parabolic architecture.
Nothing was done to parallel the gingival plane with the HPC. The right
bicuspids were not touched. The gingival asymmetry was preserved rather
than matching the gingival plane to the HPC. The periodontist ignored the
photographs that showed exactly what was necessary to make this case a
cosmetic success.
42
Figure 24: Camera angles alter length perception, but not plane perception. This photograph was shot from too high above the teeth.
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Figure 26: Photo at six weeks post-op. A second surgery was done at this
time to remove tissue from teeth #6–#9.
27
Figure 27: Even after the second surgery, the gingival plane is still
0.7 degrees off the HPC. The line drawn on tooth #8 represents the original
length of the central before the two surgeries.
28
Figure 28: Cosmetic issues. Cuspid gingival plane is off 0.7 degrees. Gingival levels of the incisors are uneven or gull-winged in shape. Gingival length
of #10 is longer than #7. There is a significant step between #5 & #6, and
#10 & #11 should not have been lengthened. The #10 space was left too
wide by the orthodontist, and the midline was not properly managed.
29a
29b
29c
29d
Figures 29a–29d: Outline of the teeth at 75 percent length and width proportion shows the ideal angle of the case relative to the HPC. Unfortunately,
the gingival plane must be followed, which leaves one of two options: 1) angle the incisal edges to follow the gingival plane, thus creating a “downhill
smile” that will not have the incisal edges parallel to the HPC or 2) shorten the incisal length of the teeth on the right to make the case incisally parallel
to the HPC, thus creating contralateral teeth of different lengths. Both of these options are a cosmetic compromise that could have been avoided if the
periodontist had followed the restorative dentist’s request to level the gingiva with the HPC.
Digital Communication of Critical Cosmetic Restorative Guidelines
43
30
Diagnostic waxing, case planning
and finishing using an incorrect
HPC is a sure way to compromise
Figure 30: Another case by the same periodontist who ignored the HPC
when treating the gingival plane. It is advised to use computer analysis of
digital photographs to communicate important cosmetic elements to the
patient, staff, specialists (periodontist, orthodontist, implantologist) and the
laboratory. Use your staff to do most of the work required for the protocol.
the cosmetic outcome of the case.
31a
31b
31c
31d
Figures 31a–31d: This case shows a violent discrepancy between the surgical gingival line and the HPC. Fortunately, the difference in the incisal length
of contralateral teeth did not compromise the case too much. The patient was thrilled. This case will be presented in its entirety in the seminar titled
“Simplifying Complex Cosmetic and Restorative Dentistry,” which will be presented in Clearwater, Fla., and San Francisco, Calif., in early 2013. CM
Dr. Bill Strupp practices in Clearwater, Fla., and lectures internationally on the subject of comprehensive cosmetic and restorative dentistry. He also publishes “Crown & Bridge
UPDATE,” aimed at educating dentists in better dentistry. Contact him at 800-235-2515, bill@strupp.com or by visiting www.strupp.com.
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Interview with Dr. John Harden
– INTERVIEW of John W. Harden Jr., DMD
by Michael C. DiTolla, DDS, FAGD
Dr. John Harden is a Glidewell Laboratories customer and fellow
speaker, who will be presenting at the 2013 CDA meeting in
Anaheim, Calif. After learning that his program will be on hospital
dentistry, it dawned on me that I had never interviewed a dentist
in Chairside who specializes in this area. John has hundreds of
stories about the type of unpredictable cases that can be thrown
at you when working in the hospital setting, and he recently took
the time to sit down and share a few. Enjoy!
Interview with Dr. John Harden
49
Dr. Michael DiTolla: In Chairside magazine, we haven’t had
the opportunity to talk to someone who does a lot of hospital or
sedation dentistry. Tell me a little bit about your background,
especially what you did after dental school that led you to where
you are today.
Dr. John Harden: I graduated from the Medical College of
Georgia School of Dentistry in 1978, and then I practiced for
about five-and-a-half years in downtown Atlanta. I met my
present wife, who is in anesthesia, and I got very interested
in anesthesia. So I went to Chicago to the Illinois Masonic
Medical Center, which is a University of Illinois teaching
hospital, and I did a residency program in anesthesiology.
The program accepted one dentist with the physicians, and
I went through with 17 physicians.
After I finished that program, I came back to Atlanta and
started going around giving anesthesia for other dentists.
I also worked in a large clinic and, in about 1987, started
up another practice. And I continued going around giving
anesthesia for other dentists in their offices. But as business
built up, I just didn’t have time to do that. I had to spend
more and more time in the office, and of course we gave
anesthesia for our own patients. This was mainly deep IV
sedation; we didn’t give any general anesthetics at all. I
got involved with hospital dentistry at Emory University
Hospital, which is where I am right now. As the years went
by, we started doing more and more hospital dentistry, and
that’s our prime focus right now.
MD: When you were doing anesthesia for other dentists, what
type of procedures were you mainly going to their offices for?
JH: Extraction of third molars and periodontal surgery, and
sometimes other miscellaneous general dental procedures.
But those are the main things we did. We had a lot of general dentists taking out third molars. I would carry all of
my equipment with me, including my own oxygen supply.
I didn’t want to take a chance on anything. We mainly did
sedation with Versed (midazolam) and fentanyl.
MD: What was your experience in terms of safety over those
years? Since you were doing more deep IV sedation as opposed
to general anesthesia, it sounds like it was probably a pretty
safe procedure.
JH: It was a very safe procedure, and we never had any
problems at all. I basically did it the way I was trained as
a resident in Chicago. We never had any adverse reactions.
Every now and then we had a few patients where once I got
on site I realized we couldn’t do the case. There was one
case where I showed up to give anesthesia on a guy who’d
had a heart attack a couple of months before. I realized that
we weren’t going to be able to do anything on the patient,
and that we needed to wait at least six months and get
clearance from a cardiologist. But, overall, we had a great
safety record.
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MD: So were these mainly GPs or surgeons taking out these
wisdom teeth?
JH: These were mainly GPs that I gave anesthesia for. They
were doing third molars and other miscellaneous procedures. I’ve had periodontists and prosthodontists come to
my office and have me sedate their patients. Over the years,
we’ve gravitated mainly to hospital dentistry and sedation.
MD: I know a lot of general dentists who don’t enjoy taking
out four third molars, especially if they’re partially impacted.
I always thought that their discomfort came from the surgery
itself, but I wonder, if those dentists were able to have a
patient be in deep IV sedation, would they not feel a little more
confident taking on those cases? I think part of their discomfort
comes from the patient being awake.
JH: They do much better with IV sedation — absolutely.
MD: Don’t you get the feeling that more dentists would
probably attempt that procedure if they had someone doing
IV sedation in their practice?
JH: Absolutely they would, because many times you get
too involved with the procedure and you can’t adequately
monitor the patient. Sometimes it’s difficult to do both. Most
general dental procedures are rather long as opposed to
oral surgeries, where the surgeon goes in and gets out four
third molars in 30 to 45 minutes at the most.
MD: And I’d assume that even those oral surgeons would take
a lot longer than 30 or 45 minutes if the patient was awake.
JH: Oh absolutely. There is no question about that. Third
molar surgery is a very difficult surgery when you have
bony impactions. There’s a lot of post-op pain associated
with it, too.
MD: So how did you get introduced to hospital dentistry? Like
most of our readers probably, I have been involved in very few
hospital dentistry cases over the years.
JH: When I was in Chicago doing anesthesia, they had a big
general practice residency program there that did a lot of
dentistry for the handicapped. I used to put a lot of those
patients to sleep with full-blown general anesthetics. So I
watched the general practice residents and got to know
them well and decided to do that when I came back to
Atlanta. I applied to be on the medical staff and started
doing hospital cases in 1988. And we’ve done many hospital
cases over the years — the sickest of the sick. And in as
much as Emory University Hospital is a teaching hospital
for a major university, they will treat anybody. It doesn’t
matter how sick they are. They can handle anyone.
On my website is a list of many of the different types of
cases that I’ve done. One particular type that we have
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enjoyed doing is renal transplant cases, where you have to
clean the patient up prior to the transplant and write a letter
certifying to the transplant surgeon that there are no sources
of dental infection. But the problem with these patients is
that they often have out-of-control hypertension, in that
top 5 percent, where it’s called malignant hypertension.
You really have to treat them in an operating room;
there is no way you can manage it in the office, because
medication has to be given to keep their pressure down.
Many times these patients have to go to the ICU for blood
pressure control. The last case I did was a female patient
with end-stage renal disease, hyperparathyroidism and
out-of-control hypertension. We had to give medication in
the recovery room because she was over 200 systolic and
120 diastolic. If you typically do patients like this in the
office you can get into real trouble. Many times you have
to have a nephrologist, a kidney specialist, on standby to
manage the hypertension after the OR case. So those are
some of the types of patients, but I actually got into that by
watching the general practice residents in Chicago when
I was an anesthesia resident. So now we do it routinely. I
get referrals from very difficult patients, such as those with
Down syndrome, cerebral palsy, developmental delay and
severe cardiac disease.
MD: Are you providing the anesthesia and doing the dentistry
on those cases?
JH: Oh no. The Emory University School of Medicine runs
the anesthesia there and they have attending anesthesiologists. But most of the anesthesia is given by physician
assistants (PAs) in anesthesia and Certified Registered Nurse
Anesthetists (CRNAs). The PAs in anesthesia have a fouryear college degree and have completed a two-year PA
training program. The CRNAs have a B.S. in nursing and
two to three years of anesthesia training. They are both
very, very good. So they give the anesthesia and I just do
the dentistry. I have an assistant who is credentialed in
the hospital system who goes with me and assists me in
doing these cases. They can last anywhere from two or three
hours to seven or eight hours, when we have a lot to do.
Many times when we go down there we really don’t know
what we’re going to have to do, because we can’t examine
the patient and they’re unmanageable in the office. So we
do the exam — I have digital radiography in the operating
room and we take all the X-rays there and formulate the
treatment plan — and then proceed to do everything.
MD: So you walk into these anesthetized cases, where you’re
trying to cram in three or four appointments, and you have
no idea what you’re going to be doing?
JH: Yeah, we carry all the operative stuff. We carry endo
gear with us. I carry an Aseptico® endodontic handpiece
(Aseptico Inc.; Woodinville, Wash.) and the SybronEndo
Twisted Files™ (SybronEndo Corporation; Orange, Calif.),
and I do the endo from start to finish, whether it’s anterior,
bicuspid or a molar.
MD: Are you also doing extractions?
JH: If there are extractions, I’ll have an oral surgeon come
in and take out the teeth at the beginning of the case. They’ll
suture them up and leave, and then I’ll do their operative.
I do take teeth out though, but the problem is, as in a
general practice, I’m too busy doing restorative. As another
example, a young lady I’ve been treating for some time,
who truly is dental-phobic, said, “John, I want veneers and
ceramic crowns on the upper front six teeth.” I said: “Sure,
no problem. Can you handle the office?” She said, “I cannot,
we must go to the operating room.” So we went down there
and did the preps and impressions. The crowns were all
done by Glidewell, by the way. Glidewell does great work!
MD: Thank you!
JH: I’m not a “Michael DiTolla” from the restorative standpoint, but we do enjoy doing it. I did two ceramic crowns
and four veneers on her and they came out great. Only had
to take one impression, which is not unusual, but (laughs)
we were lucky on that one. Let me tell you about a case we
did late last year. The patient was 35, but when she was
two or three months old she had an astrocytoma resection,
a brain tumor. She survived, but obviously she had a lot of
neurologic deficits. So we took her to the OR and did two
ceramic crown preps on tooth #8 and #9, and we had to carry her back to put them in because when I touched her in
the examination appointment she started screaming. So you
see, the point is we get a lot of patients like that who are
totally unmanageable. We’ve done a lot of restorative, and
we’ve restored some implants. Now, periodontists would
typically sedate them in the office and put the implants in.
We just do the restoratives; I do not place implants at all.
MD: For the patients where I’ve had a dental anesthesiologist
come in and do deep IV sedation, I’ve noticed that crown &
bridge can be a lot harder to do on someone who is sedated. Do
you find that to be true?
JH: Well, here’s the thing: If they have a full-blown general
anesthetic, it is more difficult because you can’t take any
triple trays on a lot of these patients because the tongue
gets in the way. So, for instance, if I’m doing six, seven or
eight units on the upper, I’ll take a full-arch polysiloxane
impression on the bottom using heavy body and put it aside,
then take a separate impression up on the top. Assuming
all the teeth are present for the most part, usually you can
hand articulate those pretty well without a record. It is more
difficult though. I find myself saying “open up,” and the
patients are asleep. But finally you realize that won’t work.
It is more difficult when they’re totally asleep because
you’re working in the airway. Now if they’re intubated with
the nasal tube, like all of mine are in the operating room,
Interview with Dr. John Harden
53
there is nothing in the mouth to get in the way. Usually
they’ll put a nasal tube in and put them to sleep, and I’ll
drape the patient and put mouth props in and crank them
open and just go to town. When I have endo to do, the
rotary endo as you know is extremely fast, and with the
Sybron TF files — there are only three of them — I can go
in there and repair a bicuspid in about 15 minutes. And
have it filled in 30 minutes with two canals. I share space
with an endodontist, who has been boarded for years. We
share space, but we have separate practices, and he’s taught
me a lot of endo. That is where I’ve picked up a lot of my
endo skills.
MD: What about seating crowns on sedated people? It makes it
pretty difficult to check occlusion, doesn’t it?
JH: Absolutely, you’re 100 percent correct on that.
MD: So what do you do?
JH: I use articulating paper. Usually these patients are
paralyzed with muscle relaxants. You can take the chin,
click them together and check the occlusion without any
problem because the nondepolarizing muscle relaxants like
NORCURON® (Organon Pharmaceuticals USA; Roseland,
N.J.) make the jaw flaccid. You can click it up and down.
But that is a good point. Just like it can be very difficult to
check occlusion on someone with anesthesia, it is not easier
because they are asleep. I agree, I think it is more difficult.
MD: I’ve noticed on the couple sedation cases that I’ve done, the
tongue seems to swell. Is that something that actually happens?
JH: I think it does a little bit to be honest with you. A lot of
times in the office we’ll take full-arch triple trays or quarterarch triple trays, just for one unit maybe. In the mouth, I’ve
had problems with the tongue getting in the way, so we’ve
gone almost exclusively to full-arch trays — which ideally
is the best way for anything, really; you get all the excursive
movements right.
MD: I would assume that on these cases where you go in and
do everything, and you don’t know what you’re going to be
doing before you walk in, that financial arrangements are a
little difficult to do ahead of time.
JH: Here’s how we do that. When we go down there we
charge — and my fees are not exorbitant when you hear the
numbers — we charge a thousand dollars to go to the OR,
and we collect in full a week before the case. Otherwise,
you may not get paid. And you know how overhead is. We
haven’t had any problems in most cases doing that. Now,
if it’s somebody who has tons of stuff or a special patient,
say a Down syndrome or cerebral palsy patient, we’ll go in
there and do a complete oral exam, periodontal exam, fullmouth X-rays, whatever X-rays we think we need, formulate
a treatment plan, do the restorative and maybe do an endo
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or two. But if they require crown & bridge, we’re probably
going to have to come back and do the crown & bridge at
a separate appointment.
MD: But their parents or their guardians know that you
could go in and they might just need a debridement, or they
might need two root canals or four extractions. It’s pretty
open-ended, right?
JH: Exactly. For instance, I did a patient with tetralogy of
Fallot, which had been repaired. You know, one of the common congenital heart defects. She probably had a mental
age of 5. She had a failing pulmonary valve. We took her to
the OR, they put her to sleep, and I took full-mouth X-rays
on her, then did a full-mouth scaling. I found the supernumerary tooth in the area of #3. So I had an oral surgeon
then take her to the operating room and take out the third
molars and the supernumerary tooth. That was really all she
needed. It was a very simple case. Most of them aren’t that
simple. But every now and then you’ll find a patient who
may need five surfaces of resin and that’s it. Usually you
can’t examine these patients in the office because they’re
too combative.
MD: So it sounds like you end up doing perio too. Is most of
it debridement?
JH: Actually, full-mouth scaling and root planing is what
we mainly do. I have done perio surgery, but usually if
they need perio I’ll send them to a periodontist who sedates
patients.
MD: Compared to when you were in private practice, is there
more of a premium to work quickly and efficiently with what
you do in the hospital?
JH: Absolutely. OR time is very expensive. Let me give
an example. There was a guy in Atlanta, just a normal,
successful businessman who is an international marble
consultant. He had been to one dentist and she tried to
work on him, but he had too much of a gag reflex. I’m not
sure if she tried to give him some benzodiazepine by mouth
or not. But later he was referred to another gal who had
taken the DOCS Education course, and she was not able to
do anything. So my name came up, and he showed up to
the office one day. I said: “You’re a very busy man. Time is
a premium for you; time is money. We can go to the OR and
do this crown and one two-surface resin and be done with
it.” He said, “Do it.” So we did, and then he came back and
we put the crown in, in the office.
MD: He was OK with that?
JH: He was fine. The hospital bill for that morning was
$15,000.
MD: Hold on, the hospital bill?
JH: That’s the anesthesia and the OR cost. See, the OR is
so much for the first hour and then so much for each additional hour, and then there’s the anesthesia charge.
MD: How much did this patient pay between the operating
room fee and your fee? How much for the crown?
JH: Well, my fee for the crown was around a grand. Then
for the resin, a couple hundred bucks. What we charge is
$1,000 to go, plus what we do, with a minimum of $2,000.
MD: So this crown might have cost him $17,000?
JH: His medical insurance I’m sure paid the hospital surgery
charge — the operating room charge plus the anesthesia
charge that the anesthesiologist bills.
JH: We’ve seen some people who are off the charts! There
was one guy I treated 20 years ago, he was about 42, who
had severe aortic regurgitation. He was going to have to
have a valve pretty soon, plus he was a terrible dental phobic. I couldn’t even examine him in the office. He was sent
to me by an oral surgery colleague, who had put him out in
the office and taken some teeth out. The patient was missing a number of posterior teeth. I took him to the OR and
we got into a pre-op hold area, and he would not let the
anesthesia provider start the IV. I came up and I said: “I’m
going to give you one chance, my friend. You let this professional put that IV in or we are done.” And he shut up and let
the guy put it in. Sometimes you have to take that approach.
JH: Oh God, I would feel bad bragging about that! I would
never go out and flash up a pan and say, “I did this in one
morning to make 10 G’s.”
Here’s another thing. You can also give them Ketamine,
which you’ve probably heard of, in the thigh. It’s a dissociative anesthetic, and what you do is put 50–100 mg in
the big muscle of the thigh and they’ll go out immediately.
Then you can start the IV. We did that with the brain tumor
patient. We had to take her to a special room off the pre-op
hold area, where we had two anesthesiologists, myself and
a couple of nurses; the parents were in there, too. We gave
her a shot in the thigh and out she went.
MD: I know, I know (laughs). I just think it’s a great story that
it cost him $17,000. I guess that goes to show how strong dental
phobias can be, huh?
MD: So with the guy who was refusing the IV in the arm, are
you saying that to give it in the thigh is easier because you just
slam it in there rather than having to finesse with the IV?
MD: I want you to be proud about this and let people know that
you charged $17,000 for a crown! You don’t have to mention
that the hospital got $15,000.
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JH: It would have been easier if they had given him
ketamine. That is probably what I would have recommended
if he wouldn’t let them start the IV right off. They do that
with many kids for surgery because ketamine will put
them out.
MD: But not orally?
JH: No, not orally; it’s given intramuscularly. It can be given
in an IV. I used it when I was a resident for trauma anesthesia many years ago in Chicago. Typically, say you have
a 70 kg patient, an adult. You can give them 50–100 mg in
the thigh and that will put them out enough to allow you to
breathe them down by mask with the inhalant anesthetic —
the anesthesiologist is doing this, of course — or start the
IV and give them something like propofol.
MD: So $17,000 crowns notwithstanding, when you go in and
do these cases, can you have a fairly productive day?
JH: Oh yeah. You can have a good day — absolutely.
MD: Do you find yourself more productive in this type of setting
than when you were in private practice?
JH: Actually, it depends on what you do. There was one
case we did on a child who had developmental delay. I’ve
treated her a number of times in the OR, and one morning
I think we produced $8,000 in the OR. That’s a big day
though. You normally don’t produce that much. If you do
three or four crowns, you’re looking at $4,000 plus $1,000 to
go down there, so that’s $5,000. But you don’t do that every
day. Typically, these patients have not had incremental care
for a while, so there will be endo for obvious reasons, some
restorative, some crowns. We like to see if we can get X-rays
from another source or even our own office before we go
down there, so we know what we’re going to be doing. So
it depends on what you’re doing exactly. If you’re doing
a couple of endos, two or three crowns and a bunch of
restorative, you can have a multi-thousand-dollar morning
without any problem. Of course, you can do that in the
office, too.
MD: Well, it sounds like the average case in the OR might be
bigger than the average case in general dentistry.
JH: Probably so. I’ve been told by oral surgeons that I need
to charge more, but as you well know, that’s all relative. I
have a pedodontist friend who has a big practice here in
Atlanta and he grosses between $1.5 and $2 million. Half of
that is ortho. He had a three-year program in Connecticut
where he had a year of ortho. He is the exception to
the rule. He does a lot of hospital dentistry on very sick
kids. He sedates in the office also. I think his minimum
is $2,500 now to go to the OR. He goes only on Fridays.
Friday is his OR day. Now, obviously, that kind of production
is not typical.
MD: Right. If there is somebody reading this who says: “You
know what? That sounds like fun. I’d like to be able to help out
developmentally disabled people. I like the idea of being in a
hospital or doing some of these cases.” Or maybe they’re drawn
to the excitement of not knowing what they’re going to be getting into. How can somebody get involved?
JH: It is enjoyable, it really is. Emory University Hospital
requires a residency of some type to be on staff. Typically,
dentists who do hospital dentistry have had a GPR. A smaller
community hospital might allow you to come in and watch
and get on staff without a residency of some type. But at
Emory, and probably at USC, UCLA and all the other centers
out there, they usually require a residency of some type —
whether perio, GPR or pedo. Obviously all the oral surgeons
go to the OR. The reason for that is that they do not want to
teach you how to work in a hospital. They want you to know
already how to work in a hospital environment. There is a
lot of paperwork involved.
MD: Not only that, but it sounds like if you are not used to
working in a hospital, you’re probably not going to bring as
much stuff with you to the hospital as you need. I could see it
being a real mess.
JH: We’ve got a two-page list for the basic setup. We’ve got
a list for endo. Then we’ve got a list for crown & bridge. So
my assistant takes that list and packs the chest and the bag.
I usually get there at 5:30 in the morning for a 7:30 case. I
get everything set up and laid out and ready to go. We have
an A-dec® dental unit (A-dec Inc.; Newberg, Ore.) and an
Air Techniques PA machine that the hospital bought for me.
I get that hooked up and get the sterile water in the water
canister, get the waste canister screwed on and check all the
lines. I have every nut and bolt ready to go. They like me
when I come because I’m never late, and they never have to
go get anything. All we do is work.
MD: Do they have people scheduled after you in that OR?
JH: Probably so. There are probably 30 ORs in the main
OR. It’s a big, new 20-story hospital. I always get my cases
scheduled first thing, and I tell them I’m going to be going
until 1 or 2 p.m. maybe, so I need the OR blocked off. But
there may be a case after me, maybe a general surgery. You
never know what room you’re going to get stuck in either. I
usually go the night before to the OR, before I leave work,
to make sure that the X-ray machine is there, that it’s not off
somewhere else in the hospital, and that the dental unit is
ready and working.
MD: I would assume that it is pretty bad etiquette and that
it would make them pretty unhappy if you ran three hours
late, right?
JH: Oh good lord. Some of these general surgeons will
come in there 30 minutes late. But general surgeons have a
Interview with Dr. John Harden
57
general surgery pack. All they do is waltz in and they open
up the general surgery pack and start whacking.
But for dentistry, you’ve got to have your dental unit set
up. You’ve got to have it plugged into the medical nitrogen,
and you’ve got to have your X-ray stuff all laid out. I
carry a Hewlett-Packard laptop with a Gendex® digital
intraoral sensor (Gendex Dental Systems; Hatfield, Pa.), and
I use VixWin™ PRO software (Gendex Dental Systems). It
works great.
MD: We’re both lecturing at the next CDA meeting. Is this the
type of thing that you’re going to talk about in your program?
JH: I am. The title of it is “29 Years of Dental Anesthesiology
in Hospital Dentistry.” It’s going to be about special patient
care, whether in the office or in the operating room. I’ll be
giving a little blip on my training — I’ve got slides that go
back 30 years. We’re going to have some information on
where I trained and what the training program was like.
Then we’ll move into anesthesia in the dental office and
then into hospital dentistry. I’ve got a bunch of cases, which
seems to be what people like to see, the final product. I
could talk all day, but it’s going be crammed into an hour
and a half. It’s 278 Microsoft PowerPoint® slides.
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MD: Wow, that sounds like an action-packed one! I can tell just
by talking to you for this short time that you’ve got thousands
of stories — and all of them entertaining.
JH: We’ve had a lot of fun, we really have. The people at the
hospital are very good to me. When I go down there I treat
every nurse and every tech with the utmost respect. I don’t
throw stuff at them. I don’t holler at them. You’d really be
surprised how much they’re willing to work for you when
you treat them like that. I’ve got a lot of them from the OR
as patients.
MD: Of course. But you treat them in your office, right?
JH: Absolutely, a lot of them.
MD: They probably don’t want to be seen in the OR.
JH: Exactly! (laughs) CM
Dr. John Harden practices in Atlanta, Ga., and is on the medical staff at Emory
University Hospital Midtown. Contact him at jhdmd@bellsouth.net or visit
www.jhdmd.com.
How to
ALIGN
TEETH
– ARTICLE by
Ryan B. Swain, DMD
Six Month Smiles system provides
patient-focused approach to orthodontics
®
F
in Six Months
or all patients with malpositioned teeth, comprehensive orthodontics are the first recommendation to
conservatively correct and enhance the appearance of
their smile. Un­fortunately, the large majority of adults aren’t
willing to undergo the lengthy treatment that’s usually involved. For patients who refuse comprehensive orthodontic
treatment, general dentists are finding clear aligners to be a
solution that isn’t always as predictable or as cost effective
as they had hoped. For older teens and adults, the Six Month
Smiles® short-term orthodontic system (Six Month Smiles
Inc.; Scottsville, N.Y.) may be an option.
The Six Month Smiles system is a practical, turnkey cosmetic
braces system specifically designed for general dentists.
As a practice builder, the system enables practices to treat
a large pool of potential patients who aren’t interested in
comprehensive orthodontic treatment, but who want the
cosmetic and quality of life enhancements that a straight
smile can offer. The system enables general dentists to
provide this treatment in a very short time, and the return
on investment is immediate.
For example, dentists who attend Six Month Smiles training
seminars can return to their practices the following week,
treat patients previously unaware of this option and gen­
erate revenue from that care. General dentists don’t
require orthodontic experience to begin implementing the
system, which validates its ease of use. Dentists can attend
How to Align Teeth in Six Months
59
Figure 1: Consult with patient to determine specific cosmetic concerns.
Figure 2: Etch the teeth prior to seating the bonding trays.
Figure 3: Apply the adhesive bonding agent provided in the kit.
Figure 4: Bonding agent is placed on the brackets in the bonding trays.
a two-day hands-on training seminar, quickly learn the
process, avail themselves of mentors and support specialists,
and treat appropriate, life-changing cases when they return
to their practices.
One of the most valuable features of the PTK is that the
bonding trays are custom-fabricated based on models of
the patient’s teeth. The brackets are uniquely positioned
in the bonding trays by bracket technicians, and the trays
enable dentists to easily and precisely place brackets on the
patient’s teeth. Tooth-by-tooth chairside bracket application
is eliminated, saving dentists and their patients significant
chairtime. Once the brackets are secure, shape-memory
wires (also included in the PTK) are attached. The shapememory wires work with the prepositioned brackets to
easily move the teeth to the desired positions.
About the System
The Six Month Smiles short-term orthodontic system incorporates a patient-focused approach to treatment planning
and case selection, and a practical system for simplified
bracket and wire placement. It combines the reliability of
braces with the ease of use and general practitioner-friendly
nature of clear aligners. Key components of the system are
the hands-on training seminars, the specific brackets, the
Six Month Smiles case processing facility and the Six Month
Smiles Patient Tray Kit™ (PTK), which includes case-specific
bonding trays.
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A wide range of tooth movement can be predictably
achieved using the system, including extrusions, rotations,
intrusions and various types of tipping. However, careful
case selection and successful treatment is predicated on a
good understanding of patient expectations, what they want
Figure 5: OrthoFlow® cement (Six Month Smiles Inc.) is placed on the
brackets in the bonding trays.
Figure 6: The upper-arch bonding tray with brackets in place while the
lower arch is etched.
Figure 7: The bonding trays with brackets are cured into place.
Figure 8: The bonding trays are removed.
to achieve with braces and what is possible with the system.
The treatment approach involves correcting the patient’s chief
cosmetic complaints and not making significant changes to
the posterior occlusal scheme. The short treatment times are
due to cosmetically focused treatment goals and materials
that are designed to efficiently achieve these results.
Take impressions of the patient’s teeth. Support is available
through the Six Month Smiles online forum to help ensure
that accurate and detailed impression-taking techniques are
followed. The online forum includes mentors and instructors who are experts in providing guidance when treating
patients with specific cosmetic concerns. Send impressions
or models to the Six Month Smiles case processing facility.
Practical Protocol
Examine the patient and discuss what he specifically dislikes
about his smile and what he wants to change (Fig. 1). If the
patient’s concerns are primarily cosmetic and don’t involve
changes that are outside the realm of short-term orthodontics (i.e., changes to angle class, significant buccolingual
root movement, significant midline changes), continue
with an examination to confirm that Six Month Smiles is a
viable option.
A Six Month Smiles bracket specialist/technician sets up the
case by positioning the brackets on the models, after which
the bonding trays used for precise intraoral bracket placement are fabricated. The trays are placed in the PTK with
the other necessary materials and returned to the dentist.
Etch the teeth (Fig. 2), then apply the adhesive included in
the PTK (Figs. 3–4) and seat the bonding trays (Figs. 5–8).
Attach the appropriate wires included in the PTK to
How to Align Teeth in Six Months
61
Figure 9: The bonding trays are removed by peeling them away.
Figure 10: Attach the shape-memory wires to the brackets.
Figure 11: A typical case before treatment
Figure 12: A typical case six months after treatment
the brackets and adjust accordingly (Figs. 9, 10). Dismiss
the patient.
See the patient every four weeks for adjustments. A threewire sequence is typically followed throughout treatment.
The appropriate wires are included in the PTK. Treatment
ranges from four to nine months, depending on the case.
and a simplified, general dentist-friendly means to treat
adult patients who previously were stuck with malpositioned teeth (Figs. 11, 12). General dentists don’t require
orthodontic experience to incorporate the system into their
practices. Mentors and support specialists are available to
answer questions and supplement the thorough training
provided during the initial seminar.
When treatment is complete, the teeth are straight and an
acceptable occlusal scheme has been achieved. Remove the
wires and brackets. Because a robust retention protocol is
important for long-term orthodontic success of any kind,
determine and provide appropriate retention.
For patients with crooked teeth who aren’t willing to undergo comprehensive orthodontics, the system is a practical,
cosmetic braces option for general dentists to provide the
quality of life enhancements for their patients that a straight
smile can offer. CM
Closing Thoughts
Dr. Ryan Swain is the CEO and founder of Six Month Smiles Inc. in Scottsville, N.Y.
Contact him at ryan@sixmonthsmiles.com or visit www.sixmonthsmiles.com.
The Six Month Smiles short-term orthodontic system is a
patient-focused, lifestyle-friendly approach to orthodontics
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The Zirconia-Based
Porcelain
64
www.chairsidemagazine.com
Veneer
– ARTICLE by
Elliot Mechanic, BSc, DDS
D
entistry is both an art and a science
requiring today’s practitioner to be
versatile and ready to adapt. Not
every patient fits into the same treatment
box, calling for an identical approach.
A comprehensive examination is needed
to discover and establish a list of each
patient’s requirements.
Generally, most patients’ dental treatments
call for conventional and time-tested pro­
cedures. However, at times we are faced
with challenges that require us to be able
to think and operate “outside the box,”
relying on our ingenuity and creativity.
As practitioners gain experience, they
gather their own personal “bag of tricks”
to turn to. New procedures and innovations
in dental ma­terials provide us with increas­
ing options.
The Zirconia-Based Porcelain Veneer
65
CASE REPORT
Diagnosis and Treatment Planning
Our patient presented with a discolored upper left central
incisor (Fig. 1). His dental history noted that trauma occurred to
the tooth in his youth. His tooth tested vital and had never been
restored. Although the dark tooth bothered the patient, he had
always been reluctant to compromise its integrity. Full-coverage
crowns, pressed-ceramic veneers and bonded-composite res­
torations had been previously proposed as possible esthetic
solutions. However, these restorations called for significant
tooth reduction in order to mask the dark underlying dentin.
Since his tooth was healthy and asymptomatic, he had been
seeking a more conservative option.
Figure 1: A discolored, vital, unrestored left central incisor
Presented with the desires of the patient, we studied his
restorative choices and considered the currently available dental
materials. An ultra-thin zirconia core veneered with porcelain
was acceptable to him.
Zirconia has recently become a popular dental material because
it has high strength, is resistant to fracture and, being opaque,
has the ability to mask discolored underlying tooth structure.1
Its flexural strength of 900 to 1,100 MPa and fracture toughness
of 8 to 10 MPa make it a suitable material to create both con­
servative esthetic restorations and pontic spans for bridge
work. It can be milled to a 0.2 mm thickness and then layered
with a compatible porcelain to yield a restoration of less than
0.6 mm in total thickness. A restoration of this nature would
be minimally invasive, with the ability to alter the color of the
dark tooth to approximate that of the other central incisor.
However, in order to achieve a restoration of this description,
we require the necessary chemistry to create adhesion between
the zirconia and the tooth.
Figure 2: Shade selection (VITA Classical Shade Guide [Vident;
Brea, Calif.])
To understand the challenges of the required chemistry, we
must realize that enamel and dentin are living tissue requiring
primers and adhesives that infiltrate into created microretention
on the surface. Zirconia is a nonliving, oxide-based substrate
requiring a primer with phosphate comonomers to covalently
bond to the oxide. In order to fuse the zirconia to the tooth,
we require a cement interface that cohesively re-creates the
dentoenamel junction among the living enamel, dentin and the
inert zirconia oxide-based substrate. The resin cement chosen
should be hydrophobic and dual-curing (light- and self-curing),
as zirconia is opaque and may not allow light to totally pass
through it to fully cure the resin.2–4
Until recently, the zirconia-to-tooth bonded interface was not
possible, as hydrophobic cements do not adhere to oxides. New
products, however, such as Z-PRIME™ (Bisco Inc.; Schaumburg,
Ill.), have been developed. These are primers that utilize a com­
bined phosphate and carboxylic monomer to create a cohesive
interface, allowing the hydrophobic resin cement to create a
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Figure 3: Matrix impression was taken using a clear silicone
impression material (AFFINITY Crystal [CLINICIAN’S CHOICE])
in a clear plastic tray; this was made for later fabrication of the
bis-acryl provisional.
Dentin = Opaque
linked, cohesive hydrophilic seal between the tooth and the
indirect zirconia restoration. New universal primers (such as
Monobond® Plus [Ivoclar Vivadent; Amherst, N.Y.]) have also
been developed to accomplish this task with zirconium oxide,
metals, porcelain glass and lithium disilicate.
Clinical Treatment
An initial reference shade was taken and photographed before
any preparation to the tooth occurred. The other incisors
matched a VITA A1 shade (Fig. 2).
Enamel = Translucent
Figure 4: Creative tooth preparation, allowing room for the
ceramist to build in (layer) opacity and transparency
An impression of the unprepared tooth was then taken using a
clear plastic tray in order to have a matrix ready for subsequent
bis-acryl temporary fabrication. This clear silicone impression
material, Affinity™ Crystal (CLINICIAN’S CHOICE; New Milford,
Conn.), allows the dentist to visualize the underlying teeth as
a reference, making it easy to reposition in the patient’s mouth
when filled with the provisional material (Fig. 3).
After labial reduction of 0.6 mm, we had removed the outer
layers of translucent enamel, thus exposing the darker
underlying hue of the dentin that creates the tooth’s color.
Zirconia oxide is typically a very opaque material that does not
provide for natural translucency and light reflection. It should
be noted that several translucent zirconia-based materials
have been recently introduced into the marketplace to address
certain esthetic concerns (such as inCoris™ TZI [Sirona Dental
Systems; Charlotte, N.C.], Zenotec CAD/CAM [Wieland Dental
Systems; Danbury, Conn.] and BruxZir® Solid Zirconia [Glidewell
Laboratories; Newport Beach, Calif.]).
Figure 5: Stump shade selection was done after preparation.
Understanding the
properties of our
restorative materials and
their limitations allows
us to work creatively
within the parameters
that we are given.
Understanding the properties of our restorative materials
and their limitations allows us to work creatively within the
parameters that we are given. Incisal reduction of 1.0 mm was
created so that the incisal edge of the veneer could be fab­
ricated in pure feldspathic porcelain. This design would allow
our ceramist to create transparencies and internal coloration
similar to that of the adjacent natural tooth. In addition, deeper
preparation on the mesial and distal line angles would enable
the ceramist to develop a translucent effect in these areas (Fig. 4).
The areas of discolored dentin would be masked out with the
opaque zirconia.
Next, the shade of the underlying prepared tooth was selected
and photographed (Fig. 5). This was done in order for the
ceramist to create a corresponding die as a color reference.
Before taking the final impression of the prepared tooth, our
procedure protocol is to fabricate a preliminary provisional
restoration using a bis-acryl provisional material (such as
Luxatemp® Ultra [DMG America; Eaglewood, N.J.], Protemp™
Plus [3M ESPE; St. Paul, Minn.] or Integrity® [DENTSPLY Caulk;
Milford, Del.]). This initial provisional serves both as a preparation
The Zirconia-Based Porcelain Veneer
67
check, allowing the clinician to assess if enough tooth structure
was removed to accommodate the desired restoration, and to
also verify that the correct shade of bis-acryl provisional material
was chosen. Our office protocol calls for the dental assistants to
use an operatory timer that is set to reflect the setting time as
noted in the manufacturer’s instructions for the material being
used. The timer was set for two minutes (as required for the
Luxatemp Ultra used in this case) (Fig. 6a), and then the bisacryl material was injected into the previously obtained clear
silicone matrix impression (Fig. 6b) and positioned over the
prepared tooth. The provisional material was allowed to set on
the tooth, so that we could check to see if we had achieved
an adequate and uniform preparation to accommodate the re­­
quired thickness of the restorative material selected for this
case (Fig. 7). Any modification needed can be done to the
preparation by directly cutting through the bis-acryl, which
serves as our reference. In this case, we needed to reduce
the tooth a bit more on the labial surface (Fig. 8).5 After the
preparation was completed, a final provisional restoration was
fabricated and set aside to harden.
It is important to emphasize that, by using the bis-acryl
provisional as a preview, we eliminated the need for our dental
laboratory team to inform us of underpreparation/insufficient
room; this also obviated the need for the patient to return to our
office to modify the tooth and to take a new impression. Having
to reanesthetize, retemporize, reprepare and reimpress (the
author refers to this as “redo-a-dontics”) is not fun for either the
patient or the dentist!
The patient’s bite was taken using a rigid bis-acryl bite
registration material (LuxaBite® Ultra [DMG America]) placed
in the anterior region from canine to canine (Figs. 9a, 9b).
This is a thixotropic material that offers minimal resistance to
closure; and once set, it has a D-69 Shore scale hardness that
prevents any flexure/distortion, allowing the accurate transfer
of the patient’s bite to the articulator. Unlike many silicone bite
registration materials, it is a bis-acryl material designed to yield
precise mounting and orientation of the plaster models.6 Again,
the assistant set the operatory timer to a setting time of two
minutes, according to the manufacturer’s instructions. There
was no reason to extend the registration beyond the canines
because the posterior bite was extremely stable; in this way, it
was easily visually verified that the patient was biting in
maximum intercuspation.
The final upper impression was taken using an extremely firm
vinyl polysiloxane (VPS) impression material (Honigum® Putty
[DMG America]). The Honigum Putty, which was dispensed
from an automatic mixer (Mixstar® eMotion [DMG America]),
has a setting time of five minutes. It easily displaced the very
viscous Kopy Single Crown Light Body (Dental Savings Club)
into the subgingival sulcus, yielding a sharp and accurate
impression. The author has found that this impression material
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a
b
Figures 6a, 6b: Fabricating the bis-acryl provisional (Luxatemp
Ultra [DMG America])
Figure 7: Using the provisional to assess the preparation
Figure 8: Modifying the preparation through the provisional
(further labial reduction was needed, as noted in the preceding
prep assessment)
is pleasant tasting and is easily removed from the mouth. The
opposing lower model was taken with a VPS alginate substitute
(Status Blue® [DMG America]). Totally rigid and inflexible metal
impression trays (Rim-Lock® Metal Trays [DENTSPLY Caulk])
were used for both impressions, thus minimizing distortions
and inaccuracies.
Next, the patient’s tooth was cleaned and treated with a
desensitizing agent (Gluma® [Heraeus Kulzer; South Bend,
Ind.]). The provisional restoration was then cemented with a
translucent, dual-cured, eugenol-free resin temporary cement
(TempBond® Clear [Kerr Corp.; Orange, Calif.]).
a
Brief Synopsis of the
Dental Laboratory Protocol
At the dental lab, a sintered zirconia core (keyed to the desired
A1 shade) was milled using the Zenotec T1 7-axis CAD/CAM
milling system to a thickness of 0.2 mm (Fig. 10). A feldspathic
porcelain (Cerabien™ ZR [Kuraray America; New York, N.Y.]) was
used to create a 0.4 mm porcelain buildup (laminate) over the
zirconia substructure, yielding a total restoration thickness of
0.6 mm. The Noritake feldspathic porcelain has a coefficient of
thermal expansion carefully matched to the zirconia, permitting
the ceramist to create lifelike esthetics that display internal
detailing and transparencies. The finished zirconia veneer offers
precise marginal fit, excellent esthetics and high strength.
b
Figures 9a, 9b: Rigid bis-acryl anterior bite registration
(LuxaBite Ultra [DMG America])
Delivery of the Final Restoration
Upon receiving the restoration from the laboratory, its fit was
verified on the laboratory work model to ascertain that it met
our expectations. We then telephoned the patient to schedule
an appointment. (In our office protocol, delivery appointments
are not prescheduled according to the lab return dates, as we
always want to have the flexibility of being able to return the
case to the dental laboratory team if obvious corrections are
needed.) In this case, the restoration was acceptable as received
from the laboratory, so the internal surfaces were treated with
a zirconia primer (Z-PRIME) (Fig. 11). The phosphate monomer
in this special primer interacts with the oxide surface of the
zirconia to form a covalent bond, thus optimizing the bond
strength between the resin cement and the zirconia surface.
Figure 10: The milled zirconia core (Zenotec T1 7-axis
CAD/CAM milling system [Wieland Dental Systems Inc.])
With the patient in the chair, and before removing the
provisional, we first assessed the esthetics of the restoration
next to the natural teeth to see if they looked the same (Fig. 12).
If they had not, we would have returned the case to the dental
ceramist with photos and a description of the changes required.
Once approved, the provisional was removed by first placing
a slit in the labial surface using a flame-shaped diamond (KUT
3205 C [Dental Savings Club]). It was then separated and
removed using an EB134 instrument (Brasseler USA; Savannah,
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Figure 11: Application of the zirconia primer (Z-PRIME [BISCO
Inc.]) to the internal surface of the restoration
Ga.) (Figs. 13a–13c). The underlying prepared tooth was
cleaned with pumice, and then treated with a 32% phosphoric
acid gel (UNI-ETCH® [Bisco Inc.]) containing benzalkonium
chloride, an antimicrobial agent (Fig. 14). A universal adhesive
(ALL-BOND UNIVERSAL™ [Bisco Inc.]) with low film thickness
was then brushed on the tooth structure (Fig. 15).
Figure 12: Verifying the restoration for form and color, with the
provisional still in place
Next, a resin cement (DUO-LINK™ SE Kit [Bisco Inc.]) was
applied to the internal surface of the veneer (Fig. 16), and
then it was placed on the tooth and light-cured (VALO® LED
Curing Light (Ultradent Products Inc.; South Jordan, Utah)
(Fig. 17). The VALO LED light produces a high degree of
polymerization.7,8 Furthermore, its curing tip can be easily
placed at a 90-degree angle to the labial surface of the tooth,
allowing optimum light penetration.
Designing the tooth preparation specifically to accommodate
the application of the ceramic materials chosen in this case was
very important. This thoughtful protocol resulted in areas of
translucency, transparency and internal detailing, providing a
definitive restoration with lifelike esthetics that satisfied our
patient’s esthetic goals (Fig. 18).
a
Figure 14: Etching the tooth with a 32% phosphoric acid gel (UNI-ETCH [Bisco
Inc.]) containing benzalkonium chloride, an antimicrobial agent
b
c
Figures 13a–3c: Removing the bis-acryl provisional
Figure 15: Placing a universal adhesive (ALL-BOND UNIVERSAL [Bisco Inc.])
The Zirconia-Based Porcelain Veneer
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CLOSING COMMENTS
No single restorative material can satisfy every esthetic need.
By having current knowledge of procedures and materials
available, the practitioner is better able to adapt and satisfy the
patient’s desires. Porcelain-layered zirconia veneers can be a
useful addition to our dental “bag of tricks.” CM
Dr. Elliot Mechanic practices esthetic dentistry in Montreal, Canada. He is the esthetic
editor of Canada’s Oral Health dental journal and is on the editorial board of Dentistry
Today. Contact him via e-mail at info@drmechanic.com.
Acknowledgement
The author would like to thank Adrian Jurim, CDT, MDT, for inspiration and the exquisite
technical fabrication of this zirconia-based layered veneer (Zeneer™ [Jurim Dental Studio
Inc.; Great Neck, N.Y.]).
Figure 16: Placing the resin cement (DUO-LINK SE Kit [Bisco
Inc.])
References
1. Denry I, Kelly JR. State of the art of zirconia for dental applications. Dent Mater. 2008
Mar;24(3):299-307.
2. Tanaka R, Fujishima A, Shibata Y, Manabe A, Miyazaki T. Cooperation of phosphate
monomer and silica modification on zirconia. J Dent Res. 2008 Jul;87(7):666-70.
3. Yoshida K, Tsuo Y, Atsuta M. Bonding of dual-cured resin cement to zirconia ceramic
using phosphate acid ester monomer and zirconate coupler. J Biomed Mater Res B
Appl Biomater. 2006 Apr;77(1):28-33.
4. Dérand P, Dérand T. Bond strength of luting cements to zirconium oxide ceramics.
Int J Prosthodont. 2000 Mar-Apr;13(2):131-5.
5. Gürel G. Predictable, precise, and repeatable tooth preparation for porcelain laminate
veneers. Pract Proced Aesthet Dent. 2003 Jan-Feb;15(1):17-24.
6. Chan CA. Bite-management considerations for the restorative dentist. Dent Today.
2008 Jan;27(1):108, 110-3.
7. Price RB, Felix CA, Andreou P. Third-generation vs a second-generation LED curing
light: effect on Knoop microhardness. Compend Contin Educ Dent. 2006 Sep;27(9):
490-6.
8. Boksman L, Santos GC Jr. Principles of light-curing. Inside Dentistry. 2012 Mar;8(3):94-7.
Figure 17: The completed restoration
Disclosure: Dr. Mechanic reports no disclosures.
Reprinted by permission of Dentistry Today, © 2012 Dentistry Today.
Dentin = Opaque
Enamel = Translucent
Figure 18: The zirconia-based porcelain layered veneer demonstrating natural, lifelike details
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