and the emphasis again is being placedon minimal or no tooth reduction!'

Realizing Minimal Preparationwith Pressed Ceramic VeneersThomas E. Dudney, DMD

Tooth preparation for porcelainveneers has undergone a cyclical evolu-tion. It began in the early 1980s with min-imal or no preparation, progressed to moreaggressive tooth reduction in the 1990s,and today, has returned to very little, if any,tooth reduction when possible.

When porcelain laminate veneers werefirst introduced, the technique of acid-etch-ing the internal surface of a thin porcelainveneer and then adhesively bonding it tothe acid-etched enamel surface was newand untested. Most clinicians reduced verylittle, if any, tooth structure to keep thepreparations within the enamel layer.1Doing so enabled them to achieve the highbond strengths necessary to attach thethin porcelain shell to the facial surfaceof the tooth.2'4

Time and research have demonstratedthat the early success of porcelain veneerswas most likely because of minimal or nopreparation. An often-cited advantage offeldspathic porcelain is its need for onlya 0.4-mm to 0.5-mm reduction in toothstructure, an amount that is consideredminimally invasive.5

In the 1990s tooth preparation philoso-phies began to change when pressed ceram-ics were introduced and dentin bondingagents proved clinically successful. Pressedceramics became tremendously popular,but the materials and the techniques fortheir placement required more tooth re-duction than the placement of feldspath-ic veneers.6 Their minimal thickness shouldbe 0.6 mm to 0.8 mm, which sometimescan result in aggressive tooth preparation.7

Today, preparation philosophies havecome full circle, and the emphasis again isbeing placed on minimal or no tooth re-duction. This trend most likely is caused

by such factors as the successful market-ing to both dentists and the general pub-lic of the "prepless" veneer, thus creating agreater demand; the teachings of respect-ed clinicians who advocate minimal orno tooth preparation whenever possible(ie, depending on the clinical conditionand the desired result8); and the abilityof technicians to cut back, layer, and thindown pressed ceramic veneers to dimen-sions that require minimal or, in some cases,no tooth reduction. In fact, some ceramistsare now pressing laminate veneer restora-tions as thin as 0.4 mm.

There are many benefits of minimallyinvasive preparations, including the preser-vation of tooth structure, less postopera-tive sensitivity, less flexibility of the pre-pared tooth, healthy soft-tissue response,higher bond strengths, and longer lastingrestorations. This article provides an exam-ple, through the case presentation, of theuse of a pressable ceramic in conjunctionwith very minimal tooth preparation toachieve a beautiful, natural-looking restora-tive result. It also emphasizes the impor-tance of the provisional restorations andlaboratory communication to ensure theoverall success of a case.

CASE PRESENTATIONA 28-year-old woman presented for aconsultation because she was unhappywith the appearance of her smile (Figure 1).She specifically felt that she did not dis-play enough of her teeth when she smiled(Figure 2), and she wanted her teeth to belighter in color. Thorough clinical and peri-odontal examinations were performed,radiographs were taken, and an estheticanalysis of the patient's smile was conduct-ed. The composition elements necessary

Thomas E. Dudney, DMDPrivate Practice

Esthetic, General, and Restorative Dentistry

Alabaster, Alabama

for an esthetic and functional smile thatwere evaluated included the symmetryacross the midline, anterior and centraldominance, and regression proportion.9Additionally, the overall esthetic analysisincluded an evaluation of the patient's lipthickness, incisal curvature, tissue posi-tions, tooth shape and texture, occlusalrelationship, and other factors that wouldlend themselves to determining whetherminimal preparations would be appro-priate for this case.8

Based on the examination findings, atreatment plan was developed and therestorative options were discussed with thepatient. The patient agreed to the place-ment of 10 maxillary pressed ceramic ven-eers, which would increase incisor display,9decrease the negative space in the buccalcorridors, and improve the color of herteeth to a lighter shade (Figure 3). Thepressable material selected for this case(IPS Empress® Esthetic, Ivoclar Vivadent,Inc, Amherst, NY) requires significantlyless tooth preparation than previous mate-rials in its category.7

Impressions for study models weretaken, along with a face-bow transfer (ar-tex®, Jensen Industries, Inc, North Haven,CT), centric relation bite registration, andseveral photographs. This informationenabled the laboratory technician to workthrough the case in the most predictablemanner possible to achieve the patient'sdesired esthetic and functional results.10

This information was forwarded to thedental laboratory with a prescription re-questing a diagnostic wax-up of the antic-ipated restorations.10'1 'According to Gurel,using mock-ups, wax models, temporaries,and silicone indices provide the best esthet-ic, phonetic, and functional outcomes andenables better communication with thepatient and the laboratory technician.12

Preparation and TemporizationDuring the preparation appointment, a0.4-mm depth-cutting bur was used as aguide to ensure minimal facial reduc-tion13'14 (Figure 4). Incisal reduction wasalso minimal because the incisal lengthwould be increased (Figure 5 and Figure6). Preparation guides made from the

facial and incisal reduction (Figure 7 andFigure 8), as well as to ensure uniformityin the thickness of the porcelain.15 Usinga combination of a depth-cutting bur andpreparation guides helped to conservetooth structure and achieve predictableresults.13'14

Supragingival margins, which wouldpromote gingival health,16 were formedbecause the natural teeth demonstrated alight shade. Although interproximal elbowswere created in the preparations, none ofthe interdental contacts were broken, andall internal line angles were rounded andsmoothed.

After the tooth preparation was com-pleted, a polyether impression (Impregum™,3M ESPE, St. Paul, MN) was made, alongwith a stick bite for horizontal reference.A shade of the prepared teeth and an oc-clusal bite registration were also taken.

Because the preparations were very con-servative, an intraoral, lock-on techniquewas used to provide the patient with provi-sional restorations. A provisional materi-al that in the author s opinion demonstratesexcellent handling properties, favorabletissue response, and esthetics (Luxatemp®,Zenith/DMG Brand Division, ForemostDental EEC, Englewood, NJ) was selectedfor this case in shade BE. A putty matrix

Figure 1 Preoperative full-face view of the pa-

tient. At the time of presentation, she felt that she

did not have enough tooth display when smiling.

Figure 2 Close-up preoperative view of the

patient's natural smile. From this view, the limit-

ed tooth display when smiling is evident.

44 INSIDE DENTISTRY FEBRUARY 2009

Figure 3 This close-up retracted view demon-

strates the need to decrease the negative space

in the buccal corridors and lighten the tooth

color to satisfy the patient's expectations.

Figure 7 Preparation guides made from the

diagnostic wax-up were used to verify the facial

and incisal reduction.

(Sil-Tech® putty, Ivoclar Vivadent, Inc)made from the diagnostic wax-up wasused to fabricate the temporaries (Figure9 through Figure 12).

Provisional Restorations andLaboratory CommunicationA significant amount of information canbe gained from provisional restorations.For this reason, the closer the clinician canget them to resemble the desired defini-tive restorations, the better his or her com-munication will be with the laboratorytechnician.11'12 For example, the incisaledge position and length of central inci-sors can be determined from the provi-sional restorations and communicatedto the laboratory. This information is in-valuable information for the ceramist andcritical to the success of the case.

Therefore, it is very important to eval-uate the patient in provisional during afollow-up visit so that more accurate infor-mation can be obtained. Having the pa-tient smile naturally when not numb andspeaking phonetic sounds such as "F,""V," "S," and "E" will aid the dentist indetermining the proper length and incisaledge position. Furthermore, the dentistwill be able to evaluate the anterior guid-ance of the new incisal edge position, as wellas important smile design features such as

Figure 4 Facial view of the preparations, for

which minimal reduction was necessary and was

accomplished using a 0.4-mm depth-cutting bur.

A. }Figure 8 The preparation guides made from

the diagnostic wax-up were also used to ensure

uniformity in the thickness of the porcelain when

the veneers were fabricated.

Figure 11 To create the provisional restora-

tions, a putty matrix was filled with shade BL of

the temporary material.

able. After the patient approves of thesevarious aspects of the "preview" of the finalrestorations, an impression and pictures ofthe temporaries can be taken. Any neces-sary changes that have been made can benoted and sent to the laboratory to aidthe ceramist in achieving optimal results.

In this case, all of the treatment goals—increasing incisor display, decreasingnegative space, and lightening the toothshade—were realized with the provision-als (Figure 13). As a result, they were anexcellent blueprint for the laboratorytechnician when fabricating the finalrestorations.10

Delivery of theFinal Restorations

Figure 5 Right lateral view of the preparations.

Note that minimal incisai reduction was necessary

because the incisal length would be increased.

Figure 6 Lett lateral view of the preparations.

Again, minimal incisal reduction was necessary

because the incisal length would be increased.

Figure 9 Before placing the provisional

restorations, the preparations were spot-etched.

Figure 10 As part of the lock-on provisional-

ization technique, the preparations were painted

with an unfilled resin.

*r"*•"• "C :F PI S nr « rl

Figure 12 The putty matrix loaded with tempo-

rary material was seated over the preparations

and the material was allowed to set.

set aside to be etched, rinsed, dried, andsilanated in preparation for cementa-tion while the teeth were isolated with arubber dam.

The veneers were bonded to the teethusing a total-etch technique with a fifth-generation bonding agent (Prime & Bond®NT™, DENTSPLY Caulk, Milford, DE)and a light-cured luting cement (Variolink®Veneer, Ivoclar Vivadent, Inc) in shade+1. Excess cement was cleaned from thefacial surfaces with cotton rolls and brush-es. The restorations were then tacked inplace at the gingival margin using a 3-mmcuring-light tacking tip for 5 seconds pertooth.3 Then, the interproximal excesscement was removed with dental floss, afterwhich the restorations were light-cured

Figure 13 Close-up retracted view of the complet-

ed provisional restorations, which achieved all of the

treatment goals and were approved of by the patient

polishing paste (Porcelize™, CosmedentInc, Chicago, 1L) on a felt wheel, and thepatient was scheduled for a postopera-tive appointment.

During the follow-up visit, the resultswere evaluated, and it was agreed that thetreatment goals had been achieved (Fig-ure 14 through Figure 17). The pressedceramic veneers (IPS Empress Esthetic)were fabricated sufficiently thin to en-able minimal preparation techniques,yet create a natural-looking and estheti-cally pleasing smile.

CONCLUSIONIn recent years, greater emphasis hasbeen placed on the conservation of toothstructure and minimal preparation dur-

INSIDE DENTISTRY FEBRUARY 2009

Figure 14 Postoperative full-face view of the

patient after placement of the 10 maxillary

pressed ceramic, minimal preparation veneers.

Figure 15 Postoperative close-up view of the

patient in natural smile. Note the enhanced

tooth display and decreased negative space in

the buccal corridors, as well as trie enhanced

tooth shade.

Figure 16 Postoperative retracted close-up

view of the 10 maxillary minimal preparation

pressed ceramic veneer restorations. Note the

successful decrease in negative space in the

buccal corridors and the enhanced shade.

45

Figure 17 Postoperative 1:1 view of the defini-

tive, minimal preparation veneer restorations on

teeth Nos. 7 through 10.

to be as conservative as possible whenpreparing teeth for porcelain veneers—and their conscientious attention to detailwhen providing information to the labo-ratory— will most likely contribute to thesuccess of the case and to the longevity ofthe restorations. This case demonstratedthe use of very minimal tooth preparationto accomplish subtle changes that im-proved the appearance o f the smile, as wellas the importance of provisional restora-tions for communicating with the patientand the laboratory.

ACKNOWLEDGMENTThe author wishes to thank Frontier DentalLaboratories, Inc, and their technical teamfor fabricating the beautiful restorationsfeatured in this case presentation.

REFERENCES1. Calamia JR, Calamia CS. Porcelain laminate

veneers: reasons for 25 years of success.

Dent Clln North Am. 2007;51(2):399-417.

2. Strassler HE. Weiner S. Seven to ten-year clin-

ical evaluation of etched porcelain veneers

[abstract]. J Dent Res. 1995;74(Spec lss);176.

Abstract 1326.

3. Calamia JR. Clinical evaluation of etched

porcelain veneers. Am J Dent. 1989;2(1):9-15.

4. Strassler HE, Weiner S. Long-term clinical

evaluation of etched porcelain veneers [ab-

stract]. J Dent Res. 1998;77(Spec Iss A):223.

Abstract 1017.

5. Cho GC, Donovan TE, Chee WWL. Clinical ex-

periences with bonded porcelain laminate

veneers. J Calif Dent Assoc. 1998;26(2):

121-127.

6. Friedman MJ. Porcelain veneer restorations:

a clinician's opinion about a disturbing trend.

J Esthet Restor Dent. 2001;13(5):318-327.

7. Nash RW. Porcelain veneers: a clinical per-

spective. Contemporary Esthetics and Restor-

ative Practice. 2006;10(12):52-58.

8. Javajeri D. Considerations for planning esthet-

ic treatment with veneers involving no or

minimal preparation. J Am Dent Assoc. 2007;

138(3):331-337.

9. Snow SR. Esthetic smile analysis of maxil-

lary anterior tooth width: the golden percent-

age. J Esthet Dent. 1999;11(4):177-184.

10. Trinkner TF, Roberts M. A systematic approach

to anterior esthetics. Contemporary Esthetics

and Restorative Practice. 2003;7(l):42-49.

11. Magne P. Magne M. Use of additive wax-up and

direct intraoral mock-up for enamel preser-

vation with porcelain laminate veneers. Eur

J Esthet Dent. 2005;1(1):10-19.

12. Gurel G. Porcelain laminate veneers: minimal

tooth preparation by design. Dent C//n North

Am. 2007;51(2):419-431.

13. Rosenthal L. Preparation guidelines for less-in-

vasive cosmetic restorations. Gen Denf.2007;

55(7):624-630.

14. Bassett JL. A cognitive systematic approach

to analyzing preparation design for a difficult

space management case. Gen Dent. 2007;

55(7):664-668.

15. Brunton PA, Aminian A, Wilson NH. Tooth

preparation techniques for porcelain laminate

veneers. BrDentJ. 2000;189(5):260-262.

16. Orkin DA, Reddy J, Bradshaw D. The relation-

ship of the position of crown margins to gin-

gival health. J Prosthet Dent. 1987;57(4):

421-424.