88 INSIDE DENTISTRY—OCTOBER 2007

For a restoration to be successful clin-ically it needs to satisfy several criteria:

•mechanical/structural requirements(ie, durability) of both the tooth andthe restoration;

• esthetic requirements of position, form,and color; and

• biologic requirements of pulpal health,prevention of caries, and gingival health.

One of the crucial aspects of successfulesthetic restorative dentistry is controllinggingival contours. Physiologic contoursor emergence profiles are important forgingival health, as overcontoured restor-ations can lead to gingival inflammation(Figure 1).

Controlling the contours of final restor-ations begins with pre-planning beforeever picking up a handpiece and bur. Fi-nal 3-dimensional tooth positioning, thetype of restoration, and the desired colorchange from the existing clinical situa-tion dictate tooth structure removal andwere discussed in the two previous arti-cles in this series.1,2 This article will dis-cuss how to control the gingival contoursof the final restorations in the laboratory.

Ideally, the ceramist should work on amaster cast that has the gingival elementsintact (ie, not trimmed away). Many tech-niques have been discussed, from using asolid untrimmed cast (Figure 2) to usingcasts that use pink flexible silicone mate-rials (Figure 3) that allow the ceramist to

visualize the relationship of the free gin-gival margin to the cervical contours ofthe restoration. Both work, but with slightdifficulties. The solid cast does not use theactual dies, which makes them impossibleto use in a foil or refractory technique. Theonly way to use this technique is after thedies are divested or removed from the foil;they then must be “fit” to the solid cast. Ifthere are problems with contour or fit it isvery difficult to correct. The “soft tissuecast” technique allows the use of the mas-ter dies, but the authors and many of theircolleagues express dislike for using thismaterial with veneers or anterior crownsbecause this material is very difficult to ad-just. This article will discuss the authors’modified Geller cast technique that allows

LABtaLkLaboratory perspectives from the inside out.

Creating Physiologic Contours Using aModified Geller Cast TechniqueEdward A. McLaren, DDS; and Yi-Yuan Chang, MDC

Edward A. McLaren, DDSDirector

Center for Esthetic Dentistry

Founder and Director

UCLA Master Dental Ceramist Program

Adjunct Associate Professor

UCLA School of Dentistry

Los Angeles, California

Private Practice limited to Prosthodontics and

Esthetic Dentistry

Yi-Yuan Chang, MDCMaster Dental Ceramist

Full Time Faculty

UCLA Master Dental Ceramist

Residency Program

UCLA School of Dentistry

Los Angeles, CaliforniaFigure 1 Image of a clinical situation of overcon-tour with the associated gingival inflammation.

Figure 2 Image of a solid cast without remov-able dies.

Figure 3 A soft tissue cast with removable dies us-ing the pink PVS impression material for the gingiva.

Figure 4 Elastomeric impression with excellentmarginal detail.

Figure 5 The marginal gingiva is blocked outwith wax to support this area so that it does nottear on stone removal.

Figure 6 Sectional first pour of the masterdies upon removal from impression.

Figure 7 The sectioned dies.

Figure 8 Facial view of trimmed die. Figure 9 Sagittal view of trimmed die; notethat the palatal gingival area is not trimmed away.

Figure 10 The margins are marked, and thedies are sealed and ready for duplication.

Figure 11 The dies are placed in aduplicating ring.

removable dies and interchangeable re-fractory dies, and maintains the soft tis-sue elements in die stone.

TECHNIQUEFinal impressions should be generatedwith an elastomeric impression materialthat allows multiple pours, eg, Impregum™Garant™ Soft Light Body ImpressionMaterial by 3M ESPE (St. Paul, MN)(Figure 4). At least two pours of the im-pression will need to be made. Whenpouring impressions multiple times,sometimes the marginal area of the im-pression will tear because of the thin-ness of the impression material in thisarea. To avoid this, sticky wax can bebuilt up to fill in where the free gingivalmargin is; this supports or blocks outthe thin area of impression material thatwent subgingival during the impressionprocess (Figure 5). This will allow mul-tiple pours without tearing. The authorsmake two master-die pours in this fash-ion (Figure 6). The dies should be sec-tioned (Figure 7) and then trimmed andtapered so that there are no undercuts(Figure 8). For veneers, the lingual softtissue should not be cut away; this helpsstabilize the die in the cast and acts asan anti-rotation or seating device (Fig-ure 9). The margins are marked with ared pencil and the dies are sealed (Fig-ure 10). The master dies are then mount-ed on a duplicating device (Figure 11).A low-viscosity polyvinyl siloxane(PVS) duplicating material should bepoured into the ring around the dies(Figure 12).

Next, the duplicated master dies can bedie-spaced with one coat of die spacer onthe part of the die that is subgingival (Fig-ure 13). It has been found by the authors

INSIDE DENTISTRY—OCTOBER 2007 89

Figure 12 A low-viscosity PVS-duplicatingmaterial is poured into the duplicating ring.

Figure 13 The duplicated master die afterpouring in die stone and placing one coat of diespacer on the neck or tapered area of the dies.

Figure 14 The dies are placed back in theimpression and the die lube/separator is placedon the dies.

Figure 15 The master cast after it has beenpoured with die stone.

ONE OF THE

CRUCIAL ASPECTS

OF SUCCESSFUL

ESTHETIC

RESTORATIVE

DENTISTRY IS

CONTROLLING

GINGIVAL CONTOURS.

(Circle 8855 on Reader Service Card)

that one coat of die spacer is necessary tocompensate for the slight expansion of therefractory die. This die should be sealed,the die separator placed on it, and thedies placed back in the master impres-sion (no wax is used at this point in the

90 INSIDE DENTISTRY—OCTOBER 2007

Figure 16 Demonstration of the resolvabilityof the dies with the intact gingival elements.

Figure 17 The original master die (the onethat was previously duplicated) is die-spaced inthe region to receive the restoration.

Figure 18 The die-spaced dies are placedback in the duplicating ring and poured with PVSduplicating material as before.

Figure 19 The refractory die generated fromduplicating the die-spaced master die.

Figure 20 The master cast with the sealed refrac-tory dies in place, ready for porcelain application.

TO CREATE INTERCHANGEABLE REFRACTORY DIES FOR

THE MASTER CAST, THE ORIGINAL MASTER DIES ARE

DUPLICATED, BUT SHOULD NOT BE OTHERWISE USED

UP TO THIS POINT. THESE DIES SHOULD BE SPACED

WITH THE APPROPRIATE AMOUNT OF DIE SPACER ON

THE PREPARATION AREA JUST SHORT OF THE MARGIN.

impression so as to reproduce all of thegingival contours in stone) (Figure 14).Die stone is then poured into the full im-pression around the dies that have beenlubricated. The master cast with fully in-tact gingiva and removable dies is demon-strated in Figure 15 and Figure 16. It canbe seen at this point how much easier itwould be to visualize correct gingival con-tours than with a conventional pinned-die technique.

To create interchangeable refractorydies for the master cast, the original mas-ter dies are duplicated, but should not beotherwise used up to this point. Thesedies should be spaced with the appropri-ate amount of die spacer on the prepara-tion area just short of the margin (Figure17). The dies can be placed in a duplicating

ring and duplicated as before (Figure18). Note that these dies had no die spaceron the neck or root of the die. The dies thatwere used in the master cast have one coatof die space on the neck or root to make thesocket or hole the die fits in slightly larg-er than the die. This allows for the slightexpansion of the refractory material andallows the refractory die to seat in the mas-ter cast properly. Once the master die withdie spacer only on the preparation area isduplicated, it is poured with a refractory

material that is specific to the porcelainused (Figure 19).The dies will fit back in themaster cast and will be interchangeablewith the duplicate master dies (Figure 20).

The refractory dies should be sealed witha material that is specific to the porcelainsystem. The porcelain is built up similar-ly to other techniques, but as seen in Figure21, because of the stone replication of thegingival, it is much easier to create es-thetic and physiologic contours. Figure22 through Figure 24 represent the preop-

erative condition, conservative prepara-tions, and the final esthetic outcome ofveneers placed on teeth Nos. 6 through 11.

REFERENCES1. McLaren EA, Bazos, M. Controlling tooth

reduction and the bonded mock-up: Part I.

Inside Dentistry. 2007;3(2):96-100.

2. McLaren EA, Vigoren G. Preparations and

controlling tooth reduction Part 2: Crowns

and fixed partial dentures. Inside Dentistry.

2007;3(5):86-90.

INSIDE DENTISTRY—OCTOBER 2007 91

Figure 21 Using the modified Geller cast dur-ing the porcelain application process.

Figure 22 Preoperative condition of thepatient used to demonstrate this technique.

Figure 23 Conservative porcelain veneerpreparations.

Figure 24 The final esthetic outcome of porce-lain veneers placed on teeth Nos. 6 through 11.

(Circle 90 on Reader Service Card)