Vol. 1, No. 2, 2001 Esthetic Technique - Brasseler...

Diagnostically Based Protocolfor Tooth PreparationJohn C. Kois, DMD, MSD; Steve McGowan, CDT

Sponsored by Brasseler USA 2 Hours of Continuing Education Credit

A Supplement to Contemporary Esthetics and Restorative Practice® An MWC Publication

©2001. Dental Learning Systems Co., Inc.

Esthetic Technique™

Clinical Case Studies and Technique Review

Vol. 1, No. 2, 2001

Dear Reader:

The preparation of anterior adhesive ceramic facial veneers or full-ceramic veneers should not be a dogmatic procedure where all prepara-tions are done exactly the same way. The translucency of this conserva-tive category of restoration offers the advantage of assisting in the finalesthetic match by allowing natural tooth color to pass through. At times,however, this translucency can also be problematic, especially when try-ing to cover discolored teeth, and must be compensated for. In addition,variations in the functional demands of individual patients will requiremodifying the preparation design. For optimal adhesion, it is alwaysdesirable to keep the preparation in enamel, but sometimes this is notpossible because of many factors. Analysis of these factors and justifica-tion must be carefully considered before preparation. Finally, the restora-tive material should not require excessive tooth reduction just to satisfyfabrication criteria.

Dr. Kois and Mr. McGowan have successfully researched the subjectand written an excellent article on it for this issue of Esthetic Technique.They discuss how and why each zone of the tooth is prepared to meet thebiological requirements of the tooth. In addition, they show how function,dentofacial parameters, and periodontal concerns will often require mod-ifying the preparation criteria and design. Optimal results are achieved bytreating each patient individually and not dogmatically treating everyonethe same way. This article clearly describes and defines a philosophicaland technical approach that allows for the most esthetic and conservativeresults when using adhesive ceramic restorations.

Dental Learning Systems would like to thank Brasseler USA forsponsoring this clinical series.

Best regards,

Bruce J. Crispin, DDS, MSDirector, Esthetic ProfessionalsWoodland Hills, California

The Esthetic Technique™ series is made possible through an educational grant from Brasseler USA,

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Contemporary Esthetics and Restorative Practice® (ISSN 1523-2581, USPS 017-212) is published 12 times a year by Dental Learning Systems Co., Inc., 241 Forsgate Drive,Jamesburg, NJ 08831-0505. Copyright © 2001 by Dental Learning Systems Co., Inc./A division of Medical World Communications, Inc. Printed in the USA. All rights reserved.No part of this issue may be reproduced in any form without written permission from the publisher.

Contemporary Esthetics and Restorative Practice® is a trademark of Dental Learning Systems Co., Inc. Medical World Communications Corporate Officers: Chairman/CEO,John J. Hennessy; President, Curtis Pickelle; Chief Financial Officer, Steven J. Resnick; Chief Operating Officer, Melissa J. Warner; Vice President of Manufacturing, Frank A. Lake

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Bruce Crispin,DDS, MS

Nasser Barghi,DDS

Lee Culp, CDT

John Kois,DMD, MSD

Gerard Kugel,DMD, MS

Edward A.McLaren, DDS

Larry Rosenthal,DDS

Howard Strassler, DMD

Douglas A.Terry, DDS

Thomas F.Trinkner, DDS

ADVISORY BOARD

Dental Learning Systems Co., Inc., is an ADA Recognized Provider

Academy of General Dentistry Approved National Sponsor. FAGD/MAGD Credit

7/18/1990 to 12/31/2002

3ESTHETIC TECHNIQUE VOL. 1, NO. 2, 2001

LEARNING OBJECTIVESAfter reading this article, the reader should be able to:

• explain how a diagnostically based rationale will enhance the predictability of anterior toothrestorations.

• identify the three distinct zones of anterior toothpreparation.

• discuss the tooth reduction considerations and margin design for each zone.

A lthough technically demanding and productdependent, porcelain laminate veneers offer apredictable option for creating a successful

restorative treatment that also preserves a maximumamount of tooth structure.1-5 The risk of failure, howev-er, has been shown to increase when primarily bondingto dentin rather than enamel, when the functional rela-tionships are not managed properly, or when the toothstructure to be restored is very dark.

Concepts of anterior tooth preparation for theserestorations continue to evolve, creating confusionamong restorative dentists and laboratory technicians.

ABSTRACTA diagnostically based protocol for anterior

tooth preparations for adhesively retained

porcelain restorations offers dentists and labo-

ratory technicians new options to approaching

these restorations. Rather than designing a

preparation and restoration based more on the

needs of the products used than on the preser-

vation of the remaining tooth structure, practi-

tioners can enhance the predictability of these

restorations by concentrating simultaneously

on three distinct zones of the tooth (incisal,

middle, and cervical) and four diagnostic cate-

gories (periodontal, biomechanical, functional,

and dentofacial). The result of following the

technique presented in this article is achieving

an individualized design that offers a pre-

dictable option with minimal risks to the

remaining tooth structure.

Diagnostically Generated AnteriorTooth Preparation for AdhesivelyRetained Porcelain Restorations:Rationale and TechniqueJohn C. Kois, DMD, MSD

Steve McGowan, CDT

John C. Kois, DMD, MSD

Private Practice

in Fixed Prosthodontics

Tacoma, Washington

Steve McGowan, CDT

Kenmore, Washington

Figure 1—Preoperative facial view

of teeth Nos. 7 through 10 shows sig-

nificant discoloration and incisal

edge fracture on tooth No. 8.

Figure 2—

Radiograph

of teeth Nos.

7 through

10 shows

large endo-

dontic ac-

cess open-

ing and fill

in tooth No.

8, which is

a high bio-

mechanical

risk.

Figure 3—Preoperative facial view,

“envelope of function” reveals no

mobility, minimal wear, and low

functional risk.

4 VOL. 1, NO. 2, 2001 ESTHETIC TECHNIQUE

Unfortunately, this confusiontends to result based more on theneeds of new and innovative prod-ucts, which is commercially bias-ed, rather than on concern aboutremaining tooth structure.

In contrast, a rationale that isdiagnostically based provides theopportunity to create a frameworkof understanding that will enhancethe predictability of these restora-tions in tandem with the improve-ments and benefits from new tech-nologies. To create a restorationthat exceeds our patients’ expecta-tions with minimal compromise toremaining or existing tooth struc-ture, the parameters of anteriortooth preparation are focused onthree distinct zones: incisal, mid-dle, and cervical.

Within each zone, the tooth

preparation is generated by simul-taneously understanding the bio-mechanical behavior of the toothstructure, functional requirements,dentofacial parameters, and theperiodontal concerns of thepatient. Therefore, the ultimatedesign of the tooth preparation isminimized by the needs dictated by

product thickness and maximizedto benefit the final restorativeresult (Figures 1 through 7).

INCISAL ZONERepresenting the initial starting

point, restoration of the incisalzone is based primarily on the func-tional and esthetic requirements ofthe individual patient. If the incisaledge position is correct in the faceand in harmony with the smile, novertical tooth reduction is neces-sary. This, unfortunately, does notprovide the laboratory technicianany flexibility to modify shape,position, or incisal translucency.Vertical reduction is not desirable,however, if the functional risk ishigh. If functional risk is low, thedentist has more flexibility todevelop incisal reduction based on

Figure 4—Final tooth preparation

on No. 8. There is excessive reduc-

tion of the incisal edge on the mesial

(dictated by fracture), butt-fit mar-

gin design, and a more excessive

cervical reduction (0.7 mm)

because of the high dentofacial risk

and low periodontal risk.

Figure 5—Laboratory communica-

tion photograph includes shade tabs

for value and supports high dentofa-

cial risk.


of teeth in occlusion.

Figure 7—Final view in occlusion.

The veneer on tooth No. 8 is adhesive-

ly retained primarily to enamel,

which is not perfect esthetically.

However, maximum preservation of

tooth structure for a predictable long-

term result was accomplished.


of teeth Nos. 7 through 10 shows

hopeless prognosis for tooth No. 8

and discolored interproximal com-

posites.

Figure 9—Preoperative incisal view

of functional relationship shows

slight malposition of teeth Nos. 9

and 10; low functional risk.

Porcelain laminate

veneers offer a

predictable option for

creating a successful

restorative treatment

that also preserves a

maximum amount of

tooth structure.


esthetic dentofacial veneers (Fig-ures 8 and 9).

Reduction ConsiderationsIdeally, the vertical incisal

reduction is 2.0 mm from thedesired position, where it does notcreate a biomechanical compro-mise to the remaining tooth struc-ture. It also offers minimal func-tional risk to the porcelain extend-ing beyond the incisal edge, andgives the laboratory technicianesthetic options to alter toothform and build incisal effects inthe porcelain. In addition, strictguidelines about not reducing theincisal zone more than 2 mm verti-cally as discussed in previous arti-cles are not supported by clinicalfindings. Unsupported verticalincisal porcelain even greater than 4 mm is predictable if the

angle of anterior guidance andenvelope of function are con-trolled (Table 1).

Margin DesignMost practitioners recommend

a lingual chamfer margin design,which is acceptable, although it isnot ideal.6 It appears more prudentto develop a butt margin designincisally, with its lingual compo-

nent in enamel and its facial axialline angle rounded. This allows thetechnician an opportunity to blendthe porcelain so that the outline ofthe preparation will never be visi-ble facially. In addition, the techni-cian and dentist will then have mul-tiple paths of insertion, for simplic-ity (Figures 10 through 13).

MIDDLE ZONEThe key concern for this zone

is performing minimal facialreduction that retains tooth struc-ture comparable to the retainedenamel to optimize the limitationsof composite technology. This willprovide a unique blend of stiffnessvs flexibility and preserve the bio-mechanical behavior of the origi-nal tooth.7-12 Unfortunately, thismust be balanced by the need tocreate sufficient porcelain thick-

Figure 10—The Brasseler tooth

preparation kit systema includes all

of the burs necessary for tooth

preparation and insertion of indi-

rect restorations.

Figure 11—Facial view of tooth

preparation technique for adhesive-

ly retained porcelain restorations.

Step 1, incisal zone. Incisal edge

reduction depth cuts with a 330 MW.

a Brasseler USA®, Savannah, GA 31419; 800-841-4522

TABLE 1—INCISAL ZONE

aBrasseler USA®, Savannah, GA 31419; 800-841-4522

The parameters of

anterior tooth

preparation are focused

on three distinct zones:

incisal, middle, and

cervical.

Figure 12—Facial view, step 1,

incisal zone. Gross reduction using

a KS 7a bur.

Key: Develop optimal incisalposition for esthetics and function

Objective: 2.0-mm vertical reduction

Margin Design: ButtLingual finish line

in enamel

Instrumentation: 330 MWa

KS 0 Mediuma

KS 7a

Consider Alteration of Incisal ZoneReduction When: Example 1 Use less reduction if:

Low-risk dentofacialHigh-risk function

Example 2 Use more reduction if:High-risk dentofacial Low-risk function

ness, which is required for opti-mum esthetic development.

The mean facial enamel thick-ness in the middle zone is 0.8 mm to0.9 mm.13 Therefore, while facial re-duction less than this amount isdesirable, maintaining the thicknessof porcelain less than this amount

will create many challenges for thelaboratory technician and elimi-nate options for any core-support-ed systems.

Reduction RequirementsTo maintain enamel facially

and recreate the original biome-chanical behavior of the tooth, a0.5-mm to 0.7-mm reduction isideal. Interproximal finish linesshould be terminated in enamel tominimize microleakage, and allsharp corners should be eliminatedto minimize stress concentration inthe porcelain as well as seatingconcerns for the restoration. Basedon functional relationships, asmuch lingual enamel as possible

should be preserved to minimizeopposing wear. Dentofacial para-meters contribute to significantconcerns based on a preferencefor using only a clear resin-lutingagent to develop imperceptiblerestorations.

For normal-colored teeth pro-viding 1 or 2 levels of shade change(ie, A3 to A1), reduction require-ments of 0.5 mm to 0.7 mm are suf-ficient. However, for tetracycline-stained or very dark teeth, the max-imum reduction of 0.8 mm to 0.9mm is more prudent.

As usual, and especially inthese situations, the individual tal-ents of the laboratory technician arefar more important than the specif-


Figure 14—Lateral view, step 2,

middle zone. Facial reduction depth

guide using a KS 0 medium bur.

Note that this is approximately half

the 1.0-mm diameter.

Figure 15—Facial view, step 2.

Completion of facial depth guide

using a KS 0 medium bur. Note that

this step does not include the cervi-

cal zone.


incisal reduction complete. Note

that the vertical reduction is slight-

ly less than the ideal 2 mm because

of the need to increase the length of

the final result based on dentofacial

parameters.

Restoration of the

incisal zone is

based primarily on the

functional and esthetic

requirements of the

individual patient.

TABLE 2—MIDDLE ZONE

Key: Maintain enamelMinimal structural

compromise

Objective: 0.5-mm to 0.6-mm—normal-colored teethreduction

0.7-mm to 0.9-mm—darker-colored teethreduction

Bevel facial incisal edgeProximal finish lines in

enamel

Margin Design:Option 1 Maintain contact point if no

proximal restorationsOption 2 Open contact point if pre-

vious caries restorationsor to change tooth form

Instrumentation:KS 0 depth guide ≈ 1/2

Diameter 0.5 mmKS 7—gross reductionKS 0—complete remaining

preparation

Consider Alteration of Middle ZoneReduction When:Example Dark-colored tooth

High-risk biomechanics High-risk function High-risk dentofacial Use 0.6-mm to 0.7-mm

facial reduction

ic brand of porcelain used. An un-derstanding of layering techniques,fluorescence, and optical propertiesof the materials used is essential.

In addition, the clinician mustdecide whether to maintain or elim-inate the proximal contact from adentofacial perspective. This deci-sion may be based solely on theneed to alter the tooth form orshape. This allows proper spacedistribution and the creation ofteeth in proper proportion. From abiomechanical perspective, previ-ous proximal restorations will

necessitate more significant reduc-tion to allow the finish line locationthat terminates on enamel lingually(Table 2).

Margin DesignThe facial incisal aspect of the

preparation must be rounded andbeveled slightly to create an invisi-ble transition of porcelain to theincisal edge and to eliminate stressconcentration and seating con-cerns. All other aspects maintain abutt type of finish line (Figures 10and 14 through 17).

CERVICAL ZONEThe key concerns in this zone

are similar to the middle zone



middle zone. Facial reduction

depth guide using a KS 0 medi-

um bur. Note that this is

approximately half the 1.0-mm

diameter.

Figure 15—Facial view, step 2.

Completion of facial depth guide

using a KS 0 medium bur. Note that

this step does not include the cervi-

cal zone.


middle zone. Gross reduction using

a KS 7 super-coarse bur.

The key concern

for the middle zone

is performing minimal

facial reduction that

retains tooth structure

comparable to the

retained enamel.

TABLE 3—CERVICAL ZONE

Key: Preserve enamelEsthetics requirements

Objective: 0.3-mm reduction requirement for normal-colored tooth

0.6-mm to 0.9-mm reduction for dark- tovery dark-colored teeth

Margin Design:Option 1 Supragingival margin

location• Normal tooth color• Minimal change in tooth

formOption 2 Intracrevicular location

• Dark color• Change shape• Close gingival embrasures

Instrumentation:KS 0

Consider Alteration of Cervical ZoneReduction When:Example 1 High-risk periodontal

High-risk dentofacialLow-risk biomechanicsLow-risk functionAxial reduction 0.3 to

0.9 mm Intracrevicular margin

location May be primarily in

dentinExample 2 High-risk biomechanics

High-risk functionLow-risk functionLow-risk periodontal0.3-mm supragingival

margin location Will be in enamel

except that the enamel is only 0.3mm to 0.4 mm thick. In addition,the periodontium complicates themanagement. The preference tomaintain enamel, control color,alter tooth form, minimize flex-ure, and preserve biologic widthcombine to provide additionalunique challenges to the labora-tory technician and clinician.

Reduction RequirementsTo preserve enamel, ideal

reduction should be no more than0.3 mm to 0.4 mm. This minimizesmicroleakage resulting from morepredictable enamel bonding andminimizes the biomechanical com-promises to the remaining toothstructure. This is especially criticalwith endodontically treated teeth.The larger the access opening andthe greater the removal of internaltooth structure, the more critical theconcerns for cervical reduction.This is especially a concern for ahigh-risk functional patient wheretooth flexure is potentially greater.

Biomechanically and function-ally, the minimal cervical reduction

requirements are often at odds withthe dentofacial concerns. When theteeth are normal color, a 0.3-mmreduction remains ideal for theporcelain to perfectly blend in, cre-ating the contact lens effect. This isonly true, however, with clear lut-ing cement. Unfortunately, whenteeth are darker than A3 and therequirements for the patient dictateusing A1 or B1 shades, more reduc-tion is necessary. As a generalguideline, an additional 0.2 mm ofreduction is necessary for eachadditional shade change.

Obviously, these increasedreduction requirements compro-mise the biomechanics and func-tional concerns of the teeth.Therefore, the dentist must decidewhere to develop the most appro-priate compromise. The priority inthis decision is dictated by the indi-vidual tooth and patient concerns,not by the needs of the restorativematerial (Table 3).

Margin DesignFrom a periodontal perspec-

tive, supragingival margins areideal. Concepts of intracreviculartooth preparation have been previ-ously discussed14,15 and are not anydifferent for these restorations.From a biomechanical perspective,the actual configuration of the fin-ish line exhibits little influence onstress variation in the porcelain.The most significant factor in mini-mizing marginal failure is ultimate-

ly the luting layer (Figures 10, 18,and 19).16,17

SUMMARYThis article presented a diag-

nostically generated protocol foranterior tooth preparation foradhesively retained porcelainrestorations. This approach elimi-nates a standardized design basedsolely on the requirements ofrestorative materials. By shiftingthe focus to three distinct zones ofthe tooth and four diagnostic cate-gories of periodontal, biomechani-cal, functional, and dentofacialparameters, the clinician can cre-ate an individualized design.Therefore, this design is determinedbased on the need to minimize riskin the highest risk categories. Withthis approach, we can achieve thebest possible result with minimalrisks to the remaining tooth struc-ture and the best chance for longevi-ty (Figures 20 and 21).

REFERENCES1. Peumans M, Van Meerbeek B,

Lambrechts P, et al: Five-year clinicalperformance of porcelain veneers.


Figure 19—Occlusal view, step 3,

cervical zone. Reduction is complete

and all restorations are replaced.

Note that all margins terminate in

enamel.

Figure 18—Occlusal view, step 3,

cervical zone. Reduction with KS 0.

Previous restorations were removed.

The implant healing abutment is

visible on tooth No. 8.

Based on functional

relationships,

as much lingual enamel

as possible should be

preserved to minimize

opposing wear.


middle zone. The facial reduction is

complete.

The individual

talents of the

laboratory technician

are far more important

than the specific brand

of porcelain used.

Quintessence Int 29(4):211-221, 1998.2. Dumfahrt H: Porcelain laminate

veneers. A retrospective evaluation after1 to 10 years of service: Part 1—Clinicalprocedure. Int J Prosthodont 12(6):505-513, 1999.

3. Dumfahrt H, Schäffer H: Porcelain lami-nate veneers. A retrospective evaluationafter 1 to 10 years of service: Part II—clinical results. Int J Prosthodont

13(1):9-18, 2000.4. Nattress BR, Youngson CC, Patterson

CJ, et al: An in vitro assessment of toothpreparations for porcelain veneerrestorations. J Dent 23(3):165-170, 1995.

5. Friedman MJ: A 15-year review of porce-

lain veneer failure: a clinician’s observa-tions. Compend Contin Educ Dent

19(6):625-638, 1998.6. Castelnuovo J, Tjan A, Phillips K, et al:

Fracture load and mode of failure ofceramic veneers with different prepara-tions. J Prosthet Dent 83(2):171-180, 2000.

7. Magne P, Kwon KR, Belser UC, et al:Crack propensity of porcelain laminateveneers: a simulated operatory evalua-tion. J Prosthet Dent 81(3):327-334, 1999.

8. Magne P, Douglas WH: Cumulativeeffects of successive restorative proce-dures on anterior crown flexure: intactversus veneered incisors. Quintessence

Int 31(1):5-18, 2000.

9. Magne P, Versluis A, Douglas WH: Effectof luting composite shrinkage and ther-mal loads on the stress distribution inporcelain laminate veneers. J Prosthet

Dent 81(3):335-344, 1999.10. Magne P, Douglas WH: Porcelain

veneers: dentin bonding optimizationand biomimetic recovery of the crown.Int J Prosthodont 12(2):111-121, 1999.

11. Magne P, Versluis A, Douglas WH:Rationalization of incisor shape: experi-mental-numerical analysis. J Prosthet

Dent 81(3):345-355, 1999.12. Magne P, Douglas WH: Rationalization

of esthetics restorative dentistry basedon biomimetics. J Esthet Dent 11(1):5-15, 1999.

13. Ferrari M, Patroni S, Balleri P:Measurement of enamel thickness inrelation to reduction for etched lami-nate veneers. Int J Periodontics

Restorative Dent 12(5):407-413, 1992.14. Kois JC: Altering gingival levels: the

restorative connection, part I: biologicalvariables. J Esthetic Dent 6(1):3-9, 1994.

15. Kois JC: New paradigms for anteriortooth preparation: rationale and tech-nique. Contemporary Esthetic Den-

tistry 2(1):1-8, 1996.16. Tjan AH, Dunn JR, Sanderson IR:

Microleakage patterns of porcelain andcastable ceramic laminate veneers. J Prosthet Dent 61(3):276-282, 1989.

17. Troedson M, Derand T: Effect of margindesign, cement polymerization, and angleof loading on stress in porcelain veneers. JProsthet Dent 82(5):518-524, 1999.


Dental Learning Systems Co., Inc., is an ADA Recognized Provider

Academy of General Dentistry Approved National Sponsor FAGD/MAGD Credit

7/18/1990 to 12/31/2002

Figure 20—Facial view of teeth Nos.

6 through 11, at time of delivery from

the lab. The implant restoration on

tooth No. 8 was fabricated with a

custom abutment and the metal-

ceramic crown was veneered with

Duceram®,b to match the adjacent

feldspathic Duceram® veneers.

(bDucera Dental GmbH and Co, KGJ, Germany)

Figure 21—Facial view of teeth Nos.

6 through 11, final result. Note

adhesively retained porcelain

restorations on teeth Nos. 6, 7, 9, 10,

and 11. The implant-retained

metal-ceramic crown on tooth No. 8

was completed simultaneously.

WARNING: Reading an article in Esthetics Technique™ does not necessarily qualify you to integrate new techniques or procedures into your practice. Dental Learning Systemsexpects its readers to rely on their judgment regarding their clinical expertise and recommends further education when necessary before trying to implement any new pro-cedure.

The views and opinions expressed in the article appearing in this publication are those of the author(s) and do not necessarily reflect the views or opinions of the editors, theeditorial board, or the publisher. As a matter of policy, the editors, the editorial board, the publisher, and the university affiliate do not endorse any products, medical tech-niques, or diagnoses, and publication of any material in this journal should not be construed as such an endorsement.


6. The mean facial enamel thickness in the

middle zone is:

a. 0.1 mm to 0.2 mm.b. 0.5 mm to 0.7 mm.c. 0.8 mm to 0.9 mm.d. 1.1 mm to 1.4 mm.

7. For tetracycline-stained teeth, the

maximum reduction of how many

millimeters is more prudent in the

middle zone?

a. 0.3 mm to 0.5 mmb. 0.5 mm to 0.7 mmc. 0.8 mm to 0.9 mmd. 1.1 mm to 1.3 mm

8. To preserve enamel in the cervical zone,

the ideal reduction is no more than:

a. 0.1 mm to 0.2 mm.b. 0.3 mm to 0.4 mm.c. 0.5 mm to 0.6 mm.d. 0.7 mm to 0.8 mm.

9. In general, how many additional

millimeters of reduction are necessary

for each additional shade change?

a. 0.1 mmb. 0.2 mmc. 0.3 mmd. 0.4 mm

10. The most significant factor in

minimizing marginal failure is the:

a. luting layer.b. porcelain structure.c. dentin smear layer.d. bonding temperature.

1. The parameters of anterior tooth

preparation focus on which zone?

a. incisalb. middlec. cervicald. all of the above

2. Within each zone, the tooth preparation

is generated by understanding the:

a. chemistry of composite setting.b. chemistry of etching.c. biomechanical behavior of tooth

structure.d. requirements of the porcelain.

3. The ultimate design of the tooth

preparation is minimized by the needs

dictated by product thickness and

maximized to benefit:

a. new bondable porcelain.b. shade-sensitive luting composite.c. the ultimate restorative result.d. reduction of laboratory costs.

4. The incisal zone is the initial starting

point and is based primarily on the

functional and esthetic requirements

of the:

a. individual patient.b. skill of the practitioner.c. available shades.d. available stains.

5. Unsupported vertical incisal porcelain

even greater than 4 mm is predictable

if which of the following is controlled?

a. bonding thicknessb. angle of anterior guidancec. cuspid disclusion in laterald. etching time

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Adjusting and contouring techniques to achieve

maximum esthetics and optimum function of

porcelain or polymer glass restorations:

• Adjusting and contouring porcelain extraorally: Sintereddiamonds are preferred over diamond-coated instru-ments. Sintered-diamond instruments are solid diamond-particle throughout and cut smoothly but never leaveblack marks on porcelain.

• For interproximal definition and contouring of splintedunits, use the 6942-200 diamond disc. The coarse-grit dischas a thin 0.15-mm profile to quickly cut and contourinterproximal surfaces (Figure 1).

• For emergence profile and reflective contours, use invert-ed-cone sintered diamonds (large: 7928.11.080, medium:7928.11.029, and small: 7928.11.018). Work the rotatinginstrument away from the margin and at a very slowspeed to protect the margin integrity.

• Occlusal adjustment and secondary anatomy refinement:The sintered-diamond football instrument 7379M.023 ineither friction grip or straight handpiece is designed toadjust occlusal surfaces. To define the triangular fossaand replace secondary anatomy in the now-functionalarea, use small and medium inverted sintered diamonds(Figures 2 and 3).

• Incisal adjustment: The diamond disc 952-140 is availablein friction grip, right-angle latch, and straight handpiecefor quick precise adjustment of incisal edges of porcelain

crowns or veneers. This disc features an autosafe chuck-ing center to stop rotation if the disc becomes engaged incontacts.

Polishing ceramic and polymer glass restorations:

The following steps will return to porcelain the wet

look of the glazed porcelain before adjustment.

• Polish porcelain with Brasseler USA Dialite polishers;begin with the blue coarse wheel, points, or discs to smoothscratches or further reduce the surface (Figures 4 and 5).

• The pink or medium-grit Dialite further prepares the sur-face for final high shine. Speed range of 3,000 rpm to7,000 rpm provides optimal polishing while maintaininglong instrument life.

• The gray Dialite (wheel, point, or cup) high shines theporcelain, returning the natural wet look (Figure 6).

• Dialite diamond-impregnated polishers are autoclavableand available in latch shank for intraoral use.

• For final polishing of textured and/or faceted surfaces,the Truluster Polishing Kit is recommended. The use of diamond paste and brushes does not remove surfacetexture.

• For polishing polymer glass, which is less dense thanporcelain, the Ceroshine Kit provides a diamond paste witha specific particle range suitable for polymer glass.Included in the kit are scotch brite wheels, goat-hair brush-es, a chamois wheel, and a cotton buff.

This information is provided by Brasseler USA.

Adjusting and Polishing of Porcelain and

Polymer Glass Restorations

PREP STEPS

Figure 2—Occlusal adjustments are

made using the sintered-diamond

football instrument (7379M.023).

Figure 3—Secondary anatomy is

refined with a sintered-diamond

instrument.

Figure 4—Porcelain is polished

with the Dialite blue coarse polish-

ing point.

Figure 5—The wet glazed look results

from polishing porcelain with the

Dialite blue coarse wheel polisher.

Figure 6—The gray Dialite point is

used to high shine porcelain.

Figure 1—The 6942-200 diamond

coarse-grit disc is used to quickly cut

and contour interproximal surfaces.

Vol. 1, No. 2, 2001 Esthetic Technique - Brasseler...

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Transcript of Vol. 1, No. 2, 2001 Esthetic Technique - Brasseler...