Reinforced heat-processed acrylic resin provisional restorations

RESTORATIVE

39.

MARGINS

AND

PERIODONTAL

HEALTH

Waerhaug J. Tissue reactions around artificial crowns. J Periodontol 1953;24:172-85. Karlsen K. Gingival reactions to dental restorations. Acta Odonto1 Stand 1970;28:895-904. Silness J. Periodontol conditions in patients treated with dental bridges. III. The relationship between the location of the crown margins and the periodontal condition. J Periodont Res 1970; 5~225-9. Valderhaug J, Birkeland JM. Periodontal conditions in patients 5 years following insertion of fixed prostheses. J Oral Rehabil 1976;3:237-43. Nyman S, Lindhe J. A longitudinal study of combined periodontal and prosthetic treatment of patients with advanced periodontal disease. J Periodontol 1979;50: 163-9. Youngblood JJ, Killoy WJ, Love JW, Drisko C. Effectiveness of a new home plaque removal instrument in removing subgingival and interproximal plaque: a preliminary report. Compendium of Continuing Ed Dent 1985;(suppl 6):5128. Ingber JS, Rose LF, Coslet JG. The biologic width-a concept

40. 41.

42.

43.

44.

45.

Reinforced heat-processed restorations Catherine University

J. Binkley, of Louisville,

of Dentistry,

Louisville,

Dental

and Director, Technician,

General

Practice

Department

ryTHE JOURNAL

OF PROSTHETIC

DENTISTRY

Residency

of Restorative

49.

Reprint requests to: DR. PHILIP BLOCK 7735 JEWELWEED COURT SPRINGFIELD, VA 22152

resin provisional

Irvin**

rovisional restorations in fixed prosthodontic rehabilitation are important treatment procedures, particularly if the restorations are expected to function for extended periods of time or when additional therapy is required before completion of the rehabilitation.’ This therapy may include orthodontic stabilization, extensive periodontal treatment, evaluation of a change in vertical dimension, or provision of time for pulp recession to occur before sufficient tooth structure can be removed without pulpal exposure. Basic requirements of provisional restorations include smooth surface contours, acceptable occlusion, correct vertical dimension, and esthetics.2W5 Material stability and strength are essential in maintaining these qualities over a period of time. Autopolymerizing resin is generally used to fabricate provisional restorations. G” This material is satisfactory for short-term use but exposure to saliva and other fluids results in progressive color changes, wear, and loss of Professor

48.

Ky.

P

*Assistant gram. **Certified

47.

acrylic

D.D.S.,+ and P. Thomas School

46.

in periodontics and restorative dentistry. Alpha Omegan 1977; 70:62-5. Della Russo NM. Placement of crown margins in patients with altered passive eruption. Int J Periodont Rest Dent 1984;4:5865. Wilson RD, Maynard G. Intracrevicular restorative dentistry. Int J Periodont Rest Dent 1981;1:34-49. Eissman JF, Radke RA, Noble WH. Physiologic design criteria for fixed dental restorations. Dent Clin North Am 1971;15:54368. Kaldahl WB, Becker CM, Wentz FM. Periodontal surgical preparation for specific problems in restorative dentistry. J PROSTHET DENT 1984;51:36-41.

Pro-

Dentist-

surface finish. In addition, fluid absorption by the polymer over a period of time decreases strength and stability. Heat-processed acrylic resin is inherently stronger, of greater stability, and more resistant to polymer breakdown than is autopolymerized resin. It has the advantages of color stability, maintenance of surface finish, and resistance to wear. Provisional restorations fabricated from heat-processed acrylic resin can function satisfactorily for extended periods of time.‘*-15 Long-span acrylic resin provisional restorations, however, are subject to fracture under occlusal forces. Esthetics and patient acceptance are also important considerations in provisional restorations. Typically, provisional restorations made with autopolymerizing acrylic resins lack incisal translucency, are uniform in color, and do not provide the optimum esthetics that can be found in the heat-processed materials. Esthetic restorations can be made with these resins and when reinforced, will function satisfactorily for long periods of time. This article describes a method of making reinforced heat-processed acrylic resin provisional restorations. A base metal framework is waxed, cast, and opaqued. The 689

BINKLEY

Fig. 1. teeth. Fig. 2. pattern. Fig. 3. Fig. 4. Fig. 5. Fig. 6.

690

Working

casts are made from irreversible

Wax pattern

for metal framework

hydrocolloid

is made by using

impressions

IRVIN

of prepared

16- or 1%gauge

External surfaces of metal framework are coated with opaque Wax is added over opaque framework. Full-contour wax pattern with metal framework incorporated. Wax pattern including framework is flasked for processing.

AND

sprue wax

porcelain.

JUNE

1987

VOLUME

57

NUMBER

6

REINFORCED

PROVISIONAL

RESTORATIONS

Fig. 7. Wax is boiled out. Body and incisal acrylic resins are packed over framework and then heat processed. Fig. 8. Provisional restoration is adjusted, finished, and polished. Fig. 9. Internal aspects of provisional restoration. Fig. 10. Incisal translucency is achieved by packing acrylic resin in layers. Fig. 11. Preoperative view of patient. Fig. 12. Reinforced provisional restorations are cemented with a temporary luting agent.

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691

BINKLEY

framework is incorporated in the. body resin during processing, and incisal resin is added to improve esthetics.

TECHNIQUE 1. Make full-arch impressionsof the prepared teeth with irreversible hydrocolloid. Select the appropriate shade(Bioform, Dentsply, York, Pa.). 2. Pour the impressionsin a hard stone (Fig. 1). 3. Make a face-bow transfer and centric relation records. 4. Mount the castson a semiadjustablearticulator. 5. Wax the patterns for metal framework using 16- or 18-gaugewax sprue patterns (Fig. 2). 6. lnvest and cast the framework with base metal. Removethe spruesand finish the metal. 7. 4pply opaque porcelain to the external surfacesof :he frameworks. Fire the opaqued framework in the porcelain furnace (Fig. 3). 8. Replacethe frameworks on cast, and build a wax-up If the provisional restoration (Figs. 4 and 5). 9. 1Remove the patterns with the framework from the :ast. Make processing models by gently vibrating stoneinto the patterns and then inverting the filled patterns onto a small patty of stone. 10. Invest the wax-up on the processing cast in a denture flask (Fig. 6). 11. Boil out the wax and verify the position of the framework on the processingcast (Fig. 7). Pack the body acrylic resin from the occlusal aspect to cover the framework and pack the incisal acrylic resin over the body (Biolon Crown and Bridge resin, Dentsply). 12. Heat-processthe acrylic resin in a denture curing tank. 13. Finish, adjust, and polish the restorations (Figs. 8 through 11). 14. Seat the restorations and adjust as needed.Internal surfaces and margins may be adapted by relining with autopolymerizing acrylic resin if necessary. 15. Cement the restorations with a temporary luting agent (Fig. 12).

DISCUSSION Provisional restorations made with metal reinforcement offer significant advantagesover other techniques. The advantagesinclude favorable periodontal contours, stable occlusion, strength, esthetics,and patient acceptance. The incorporation of the metal framework in the restoration reducesthe amount of acrylic resin necessary for strength in the interproximal spaces,permitting open embrasuresto facilitate the patient’s oral hygiene. Occlusal contacts and vertical dimension are well

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AND

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maintained by the heat-processedacrylic resin. The technique can provide metal occlusal stops by waxing a.ndcasting the posterior portions of the frameworks in full occlusal coverage. Increased strength is provided by the frameworks. They can be fabricated in segmentsto permit some flexing of the provisional restorations, particularly in pier abutment situations. Frameworks should be sectioned at a location of acrylic resin bulk, such as the pontic area. The provisional restorationsclosely resemblethe final restorationsin form and function. Tooth contours, pontic design,occlusion,and vertical dimensioncan be evaluated and if acceptable, duplicated in the final restorations. Patient acceptance of provisional restorations is enhancedby the natural appearanceof the acrylic resin. The layering of incisal resin over body resin provides translucency and natural shading. The surface can be highly polished and is resistant to discoloration and plaque accumulation.

SUMMARY A technique has been describedfor the fabrication of strong, esthetic, and periodontally considerable provisional restorations. The technique involves cast nonprecious metal frameworks and heat-processedacrylic resin. REFERENCES 1.

2.

3. 4.

Youdelis RA, Faucher R. Provisional restorations: an integrated approach to periodontics and restorative dentistry. Dent Clin North Am 1980;24:285-303. Shillingburg HT, Hobo S, Whitsett LD. Fundamentals of fixed prosthodontics. 2nd ed. Chicago: Quintessence Publishing Co, 1981;161-93. Preston JD. A systematic approach to the control of esthetic form. J PROSTHET DENT 1976;35:393-402. Federick DR. The provisional fixed partial denture. J PROSTHET DENT

5. 6. 7. 8.

1975;34:520-6.

Crispin BJ, Caputo AA. Color stability of temporary restorative materials. J PROSTHET DENT 1979;42:27-33. Miller SD. The anterior fixed provisional restoration: a direct method. J PROSTHET DENT 1983;50:516-19. Krug RS. Temporary resin crowns and bridges. Dent Clin North Am 1975;19:313-20. Weiner S. Fabrication of provisional acrylic resin restorations. J PROSTHET

9.

DENT 10. 11.

DENT

King CJ, Young use in the matrix

1983;50:863-4.

FA, Cleveland JL. Polycarbonate technique for temporary coverage.

resin and its J PROSTHET

1973;30:789-94.

Fritts KW, Thayer KE. Fabrication of temporary crown and fixed partial dentures. J PROSTHET DENT 1973;30:151-5. Josephson BA. A technique for temporary acrylic resin coverage in functional occlusal relationship. J PROSTHET DENT 1974;32:339-43.

12.

Davidoff SR. Heat-processed tions: an in-office procedure.

acrylic

resin provisional

J PROSTHET

restora-

DENT

1982;48:673-

57

NUMBER

5.

JUNE

1987

VOLUME

6

REINFORCED

13.

Moskowitz hydrocolloid immediate

PROVISIONAL

RESTORATIONS

ME, Loft GH, Reynolds to evaluate preparations provisional restorations.

JM. Using irreversible and fabricate temporary J PROSTHET DENT

1984;51:330-3.

14.

Morgan DW, Comella MC, Staffanou RS. A diagnostic wax-up technique. J PROSTHET DENT 1975;33:169-77. Calagna LJ. A comprehensive treatment rationale combining prosthodontics and periodontics. J PROSTHET DENT 1973;

15.

Reprmt

requests

DR. CATHERINE

to:

BINKLEY

DEI\TAL CLINIC AMBULATORY CARE BLDG. UNIVERSITY OF LOUISVILLE LOUISVILLE,

KY 40292

30:781-K

Comparison of compressive strength of solid and hollow pontic designs for ceramometal fixed partial dentures H. E. Rosenstein, D.M.D.,* M. L. Myers, and R. H. Jarvis, D.D.S., M.S.**** Eastman Dental Center, Rochester, N.Y.

D.M.D.,**

T

he design of the metal framework influences the strength of a ceramometal restoration. Many designs have been advocated and generally emphasize framework rigidity, uniform porcelain thickness, and support of the porcelain through design features such as interproximal struts, lingual shoulders, and trestle configurations.le4 Conventional framework designs incorporate solid metal pontics and external surfaces that are convex, in an effort to minimize tensile stresses within the porcelain. Recently, Shoher and Whitman’ developed a reinforced porcelain system (RPS) that involves the placement of concavities on the external surface of the framework. According to Shoher this design places the porcelain in compression during the firing cycle and results in greater strength and fracture resistance of the porcelain. Shoher’s pontic design consists of a hollow configuration with supporting belts on the buccal and lingual surfaces. The advantages of the hollow pontic design are: reduced casting weight (40%); reduced cost of metal; decreased porosity from solidification shrinkage; Semifinalist, John J. Sharry Research Award competition, College of Prosthodontists. Second place, Stanley D Tylman Research competition, Academy of Crown and Bridge Prosthodontics. *Postdoctoral student, Department of Prosthodontics. **Assistant Chairman, Department of Prosthodontics. ***Chairman, Department of Prosthodontics. ****Clinical Associate, Department of Prosthodontics.

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American American

G. N. Graser,

D.D.S.,

M.S.,***

elimination of a large heat sink, which aids soldering; and greater porcelain thickness for improved esthetics. This study compared the strength of hollow and solid pontic designs. A three-point load was placed on ceramometal specimens with both solid and hollow pontic designs to measure the fracture resistance of the porcelain. MATERIAL

AND

METHODS

Sixty metal frameworks were made for testing. The frameworks were divided into four experimental groups: solid pontics, hollow pontics, solid pontics with porcelain, and hollow pontics with porcelain. An RPS molar wax pattern (Williams Gold Refining Co., Inc., Buffalo, N.Y.) was used for the hollow pontic design. The solid pontic design was made from the same wax pattern by filling the hollow spaces with wax. The size of the framework was designed to simulate a three-unit fixed partial denture. The connectors for the pontic were 3 mm in diameter and 1 mm in length and were connected to spherical ends that were designed to seat on a test jig (Figs. 1 and 2). A stone matrix was used to position the pontic patterns so that all specimens could be made uniform. The patterns were invested using Hi-Temp investment (Whip-Mix Corp., Louisville, Ky.) according to the manufacturer’s directions. The frameworks were cast in Williams’ W-3 (Williams Gold, Buffalo, N.Y.) gold-palladium ceramic alloy. A second stone matrix was used for the porcelain

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