Direct Composite Cavity Preparation Design and Finishing Using Carbide Burs

Cavity preparation designs for direct composite restorations are continually changing. These changes are due to a variety of factors including early caries diagnosis.1-3 conservative preparatons,4-6 and an increase in bond strengths,7 among others. This is in striking contrast to the traditional amalgam preparation designs taught by G.V. Black or the exquisite gold restoration designs currently taught by R.V. Tucker.8,9 There are, however, certain basic preparation requirements for direct composite restorations that will ultimately lead to long-term restorative success.

In addition, the instrument choices available for the finishing and polishing of composite restorations are many and vary depending on composite filler particle size,10,11 shape,12 and configuration,13 among others.14,15 Ideally, finishing and polishing the widest variety of composite materials with the fewest instruments could streamline this approach.

The following 2 cases illustrate a technique and instrumentation for direct composite preparation design, finishing, and polishing in class V and class II restorative situations. 

CASE NO. 1: ANTERIOR CLASS V

The patient, a 45-year-old male, presented with the chief complaint of dark cavities in his upper front teeth (Figure 1). Following a complete examination, it was determined that the patient’s history of smoking was the major contributing factor to staining of the carious lesions in the maxillary anterior teeth. A treatment plan was formed that would include the restoration of these teeth using a direct composite resin technique with the possibility of root canal therapy where required.

Following the administration of local anesthesia, the cavity preparation for the maxillary right central incisor (tooth No. 8) was initiated by scribing a groove circumferentially to the depth of the carious lesion using a GW-1 carbide bur (SS White) in a high-speed handpiece (KaVo GENTLEforce LUX 6000B, Figure 2). This effectively creates a caries-free perimeter while removing any unsupported enamel by virtue of the GW-1 dentate bur design. Then, using a GW-330 carbide bur (SS White) with brush-like strokes, the layers of carious dentin were peeled away (Figure 3).

To remove any remaining unremineralizable infected dentin and avoid unnecessary pulpal exposure, an RA-6 acrylic polymer Smartbur (SS White) was used at 650 rpm (Figure 4). In order to achieve a harmonious, seamless, and aesthetic transition at the marginal interface, a beveled chamfer was created using an 868-024 flame-shaped coarse diamond (SS White, Figure 5). In class V composite cavity preparations, bevels have been shown to enhance retention,16 decrease microleakage,17 and improve aesthetics. To maximize the amount of light diffraction and maximize aesthetics, this bevel was created as a wavy striation pattern becoming more shallow approaching the incisal.

Following the total acid-etching technique and the application of a primer/bonding agent (Optibond, Kerr), Palfique Estelite (J. Morita USA), a spherical, submicron-filled composite resin, was placed. Studies have shown that the use of microfill-type, particle-size composites in class V restorations demonstrate lower polymerization contraction stresses and a decrease in marginal leakage when compared to hybrid composites.18,19 An initial base layer of medium-flow shade A3.5 was placed as a dentin substitute and light-cured, followed by successive increments of A3.5 paste with light-curing.

The final layer was shaped using a medium-blade titanium nitride composite placement instrument (Garrison Dental Solutions) and cured. The slightly overcontoured composite was initially reduced at the gingiva using a No. 3 10-blade SafeEnd series carbide finishing bur (SS White). The SafeEnd finishing bur series has a noncutting tip designed to trim and to finish without damaging gingival tissue. The composite was then reduced to proper contours along the gingival and upper middle thirds using a No. 7 10-blade SafeEnd series carbide finishing bur (SS White, Figure 6). Final carbide polishing was completed using a No. 7 20-blade SafeEnd series carbide finishing bur (SS White, Figure 7). The length availabilities of the SafeEnd series and the 2-step procedure greatly simplify the process. Following the use of composite polishing paste with a goat-hair brush, the case was completed (Figure 8). 

 

Figure 1. A class V cavity in the upper right central incisor. Figure 2. The cavity preparation was initiated by scribing a groove circumferentially to the depth of the carious lesion using a GW-1 carbide bur.
Figure 3. The layers of carious dentin were peeled away with brush-like strokes using a GW-330 carbide bur. Figure 4. An RA-6 Smartbur was used at 650 rpm to remove any remaining unremineralizable infected dentin and avoid unnecessary pulpal exposure.
Figure 5. In order to achieve a harmonious, seamless, and aesthetic transition at the marginal interface, a beveled chamfer was created using an 868-024 flame-shaped coarse diamond. Figure 6. The composite was reduced to proper contours along the gingival and upper middle thirds using a No. 7 10-blade SafeEnd series carbide finishing bur.
Figure 7. Carbide polishing was completed using a No. 7 20-blade SafeEnd series carbide finishing bur. Figure 8. The completed case.

 

 

Case No. 2: Posterior Class II

The patient, a 48-year-old female, presented for an initial examination and treatment plan. The lower left first and second molars (teeth Nos. 18 and 19) demonstrated failing amalgam restorations. When questioned about the history of these teeth, the patient recalled a previous fracture in tooth No. 19, where the dentist performed a “patch and fill.” Gross examination revealed a core-type restoration in the MOL cusp region of the lower left first molar adjacent to the existing amalgam (Figure 9). Radiographic examination revealed mesial and distal radiolucencies in teeth Nos. 18 and 19, respectively, suggesting the presence of interproximal carious lesions. Because of the extensive nature of the overall dentition’s restorative requirements, it was determined that definitive laboratory-fabricated restorations would be completed at a future date. Therefore, a core-based direct composite material (Core Paste Packable, Den-Mat) was selected as the ideal long-term interim restoration of choice.20

Following local anesthesia, the lower left first molar was isolated using a No. 7 Fiesta lower molar clamp (Coltène/Whaledent) and a medium gauge, 6 x 6-inch nonlatex dental dam (HY-GENIC Flexi-Dam, Coltène/Whaledent).

To initiate removal of the failing amalgam restoration in tooth No. 19, a trough or channel was created using a GW-1 carbide bur (SS White) with copious irrigation (Figure 10). Troughing avoids the unnecessary re-moval of healthy tooth structure. In addition, the GW-1 bur was selected, as it allows smooth, easy, initial penetration into the metal surfaces without chatter. Following the undermining and exposure of the restorative-tooth margin, the remaining restorative material was removed using a cross-cut fissure GW-2 carbide bur (SS White, Figure 11). The GW-2 bur design provides a faster and smoother cut and does not grab, catch, or stall in harder-to-cut materials. This bur has been used intraorally for preparation of titanium abutments,21 metal crown removal, in the rapid preparation of full-coverage preparations,22 and to gain endodontic access, among others. Following complete removal of the existing restorations, caries was removed at the distal proximal box using the bladed “dentate” ends of the GW-2 bur (Figure 12). The round end of the GW-2 eliminates any sharp interior line angles (as are often produced with square tip burs such as the No. 557), and the sharp axial cross-cut dentates create a striated axial wall surface. This serves to increase the overall “bondable” surface area and enhance the mechanical bond strength as well.

The tooth was then prepared for the final direct composite restoration using a 0.03-mm, dead-soft matrix (Hawe SuperMat Matrix system, KerrHawe SA) and wood wedges. Following application of a 20% phosphoric acid gel for 20 seconds (Etch n’ Seal, Den-Mat), Tenure A/B drops (Den-Mat) were applied (Figure 13), followed by the application of Tenure S (Den-Mat), and light-cured.

The mesial and distal interproximal boxes were filled with flowable composite resin in 2-mm increments and light-cured, followed by the application of flowable composite resin to the pulpal floor in a single, 2-mm increment and light-cured (Figure 14). It has been reported that the application of a thin layer of a flowable composite at the cervical margin as a liner underneath the packable composite enhances the marginal adaptation of the restoration.23

As previously mentioned, Core Paste Packable, a light-cured, radiopaque, packable, enamel shade core buildup material was selected as the long-term interim restorative. This nonsticky composite is packaged based on the amalgam placement technique. It allows for packing the composite pellet material into the preparation and toward the gingival seats. Here, the Core Paste Packable was placed in 3-mm increments and packed in an even layer using a medium/large multifunction plugger (Garrison Dental Solutions, Figure 15). This instrument is specifically designed to make larger class II and III composite placement easier, as the convex plugger tips help minimize pullback of the composite material. The final occlusal layer was packed to place (Figure 16), anatomically shaped, and light-cured (Figure 17).

Following gross occlusal adjustment using a 7406 Trimming & Finishing Carbide (SS White), the occlusal anatomy and lingual margin were refined and polished (Figure 18) using a No. 6 10-blade SafeEnd series carbide finishing bur (SS White). These areas were further refined and polished with the No. 6 20-blade SafeEnd series carbide finishing bur (SS White, Figure 19). Following the use of composite polishing paste with a goat-hair brush, the case was completed (Figure 20). 

 

Figure 9. The lower left first molar on presentation. Figure 10. A trough was created using a GW-1 carbide bur with copious irrigation.
Figure 11. The remaining restorative material was removed using a cross-cut fissure GW-2 carbide bur. Figure 12. Caries was removed at the distal proximal box using the bladed “dentate” ends of the GW-2 bur.
Figure 13. Using a 0.03-mm dead-soft matrix and wood wedges, the tooth was etched, and 5 coats of Tenure A/B drops were applied. Figure 14. The mesial and distal interproximal boxes were filled with flowable composite resin in 2-mm increments and light-cured, followed by the application of flowable composite resin to the pulpal floor in a single, 2-mm increment and light-cured.
Figure 15. Here, the Core Paste Packable was placed in 3-mm increments and packed in an even layer using a medium/large multifunction plugger. Figure 16. The final occlusal layer was packed to place.
Figure 17. This final layer is anatomically shaped and light-cured. Figure 18. The occlusal anatomy and lingual margin were refined and polished using a No. 6 10-blade SafeEnd series carbide finishing bur.
Figure 19. These areas were further refined and polished with the No. 6 20-blade SafeEnd series carbide finishing bur. Figure 20. The completed case.

 

References

1. Hefferren JJ. A review of approaches to the detection of dental caries. Council on Dental Materials and Devices. J Am Dent Assoc. 1973;86:1358-1364.

2. Shi XQ, Welander U, Angmar-Mansson B. Occlusal caries detection with KaVo DIAGNOdent and radiography: an in vitro comparison. Caries Res. 2000;34:151-158.

3. Eggertsson H, Analoui M, van der Veen M, et al. Detection of early interproximal caries in vitro using laser fluorescence, dye-enhanced laser fluorescence and direct visual examination. Caries Res. 1999;33:227-233.

4. Burke FJ. From extension for prevention to prevention of extension: (minimal intervention dentistry). Dent Update. 2003;30:492-502.

5. Peters MC, McLean ME. Minimally invasive operative care. I. Minimal intervention and concepts for minimally invasive cavity preparations. J Adhes Dent. 2001;3:7-16.

6. Mount GJ. Minimal intervention dentistry: rationale of cavity design. Oper Dent. 2003;28:92-99.

7. Ateyah NZ, Elhejazi AA. Shear bond strengths and microleakage of four types of dentin adhesive materials. J Contemp Dent Pract. 2004;5(1):63-73.

8. Tucker RV. Class 2 inlay cavity procedures. Oper Dent. 1982;7(2):50-54.

9. Tucker RV. Variation of inlay cavity design. J Am Dent Assoc. 1972;84:616-620.

10. Lu H, Roeder LB, Powers JM. Effect of polishing systems on the surface roughness of microhybrid composites. J Esthet Restor Dent. 2003;15(5):297-304.

11. Kaplan BA, Goldstein GR, Vijayaraghavan TV, et al. The effect of three polishing systems on the surface roughness of four hybrid composites: a profilometric and scanning electron microscopy study. J Prosthet Dent. 1996;76:34-38.

12. Roeder LB, Tate WH, Powers JM. Effect of finishing and polishing procedures on the surface roughness of packable composites. Oper Dent. 2000;25:534-543.

13. Jung M, Bruegger H, Klimek J. Surface geometry of three packable and one hybrid composite after polishing. Oper Dent. 2003;28:816-824.

14. Setcos JC, Tarim B, Suzuki S. Surface finish produced on resin composites by new polishing systems. Quintessence Int. 1999;30:169-173.

15. Marigo L, Rizzi M, La Torre G, et al. 3-D surface profile analysis: different finishing methods for resin composites. Oper Dent. 2001;26:562-568.

16. Baratieri LN, Canabarro S, Lopes GC, et al. Effect of resin viscosity and enamel beveling on the clinical performance of class V composite restorations: three-year results. Oper Dent. 2003;28:482-487.

17. Hall LH, Cochran MA, Swartz ML. Class 5 composite resin restorations: margin configurations and the distance from the CEJ. Oper Dent. 1993;18:246-250.

18. Ferracane JL, Mitchem JC. Relationship between composite contraction stress and leakage in class V cavities. Am J Dent. 2003;16:239-243.

19. Yazici AR, Baseren M, Dayangac B. The effect of flowable resin composite on microleakage in class V cavities. Oper Dent. 2003;28:42-46.

20. Clelland NL, Villarroel SC, Knobloch LA, et al. Simulated oral wear of packable composites. Oper Dent. 2003;28:830-837.

21. Vogel R. Intra-oral preparation of titanium abutments in order to obtain ideal angulations and contours. Available at: http://www.sswhiteburs.com/clinical_vogel.html. Accessed April 4, 2004.

22. Perkins S. The enamel peel technique: a systematic approach to performing a high quality crown preparation using a set of select burs. Available at http://www.sswhiteburs.com/clinical_perkins2.html. Accessed April 4, 2004.

23. Fabianelli A, Goracci C, Ferrari M. Sealing ability of packable resin composites in class II restorations. J Adhes Dent. 2003;5:217-223. 

 


 

Dr. Shuman maintains a full-time private practice outside Baltimore, Md, emphasizing reconstructive and aesthetic dentistry. He is a fellow in the Academy of General Dentistry, a fellow of the Pierre Fauchard Academy, and a member of the American Dental Association. Since 1989, Dr. Shuman has published more than 50 dental research and clinical articles that have appeared in numerous dental journals. He presents seminars and hands-on courses and has produced several educational videos including “The Joy of Clinical Dentistry” and “Do Your Dentures Suck?” as well the book Creating the Denture Practice of Your Dreams, which includes an instructional CD-Rom. These educational materials are CERP-approved for a minimum of 4 CE credits each. Dr. Shuman can be reached at (877) 4-SHUMAN or by visiting ianshuman.com.

 


 

Disclosure: Dr. Shuman has received research support from SS White in preparation for this article.