NewsletterResin-based composite veneers offer excellent interim solution
Theodore P. Croll, DDS | Steven R. Jefferies, MS, DDS, PhD
In the same way that hydrochloric acid from the stomach erodes tooth enamel in people with bulimia or gastroesophageal reflux disease, dietary acids in sustained exposure can do erosive damage to teeth. Sports drinks, carbonated beverages containing phosphoric acid and citric acid, and even natural juices with a significant acid content can literally dissolve mineral content from enamel and dentin if frequency and length of exposure time are sufficient.
A particularly damaging habit is consumption of the juice and pulp of lemons by sucking on cut fresh fruit. Lemon juice is about 5% to 6% citric acid, which has a pH between 1.8 and 2.3. The acid has a direct erosive action and also creates a highly acidic intraoral environment, increasing potential damage of attrition and abrasion due to chemical weakening of the enamel crystalline structure.
A 14-year-old girl was brought to the office by her mother for a routine 6-month appointment. She had completed orthodontic therapy 6 months before, and had developed a habit of sucking on fresh lemons several times a day.
Head and neck and intraoral examinations were unremarkable except for generalized marginal gingivitis and significant erosive damage to the labial surfaces of the maxillary central incisors (Figure 1). There were focal spots of through and through enamel dissolution, exposing small patches of dentin. The lingual enamel surfaces of the four maxillary incisors appeared smooth and lustrous, but much less erosion was detectable than on the labial surfaces. The maxillary lateral incisors had some labial surface enamel erosion that was slight compared with the central incisors.
It was explained to the patient and her mother that an adhesively bonded precision-fit porcelain restoration would be an excellent long-term solution for repairing the central incisors, but they were advised that such treatment is usually planned for late in the teen years or in early adulthood, when growth and development and full eruption of the teeth are completed.1 Adhesively bonded, direct-application resin-based composite (RBC) veneers were described as the best interim solution. A bonded smooth surface sealant procedure was suggested for the lateral incisors and the four incisor lingual surfaces, to provide a micro-restorative smooth surface sealant repair for those teeth and eliminate further erosive damage.2,3 Both procedures were described fully and pretreatment and postoperative photographs of other cases involving RBC labial veneers were shown. The mother was also advised on the relative costs of ceramic veneers and direct-application RBC veneers.
Counseling for the patient regarding cessation of the lemon-sucking habit was also provided. To highlight the problem and dramatically demonstrate lemon juice damage to teeth, extracted teeth were embedded in dental stone and then soaked in lemon juice (Figures 2 and 3). The demineralized enamel was easily scraped away with a Hollenback carver. The patient was somewhat shocked with the demonstration and appeared to be convinced of the need to cease her lemon-sucking habit.
With the aid of the dental assistant, small sample disks of several shades of RBC (Filtek™ Supreme Ultra, 3M ESPE, www.3mespe.com) were light-hardened and placed on the central and lateral incisors for color matching. They were inspected wet and dry with the overhead dental light off, so as to achieve ideal color matching. The assistant and dentist agreed that shade A1B (A1 “body”) was ideal. The need for shade layering would be determined after initial buildup of the material.
After local infiltration of ½ carpule of articaine 4% with 1/200,000 parts of epinephrine for both dental and soft tissue anesthesia, the labial surface of the right central incisor was prepared minimally, using a slow-speed, latch-type, long coarse-grit diamond cylinder (Figure 4). The preparation extended slightly into the proximal curvatures of the tooth, but care was taken to conserve tooth structure so as not to compromise eventual preparation for porcelain veneer restoration in the future (Figure 5).
Anterior matrix strips (.0015” [0.381mm]) (Strip-T, Denovo Dental, www.denovodental.com) were reshaped with contouring pliers to replicate the proximal curvatures of the tooth. The strips were positioned mesially and distally and the distal strip was stabilized with a wooden wedge. The mesial contact was tight and there was no proximal bleeding, so a wedge was not necessary for either matrix stability or hemostasis.
The tooth surface was rinsed with water spray and dried with the air stream. Adper™ Prompt™ L-Pop™ (3M ESPE) self-etching resin bonding agent was applied and gently agitated for 20 seconds and then light-cured for two 10-second exposures (Figure 6 and Figure 7).
A small increment of shade A1B of the RBC was squeezed from the delivery syringe upon the gingival third of the tooth surface. It was then patted into place using a thin tapered condensing instrument, with care to avoid incorporation of air bubbles (Figure 8). Several additional increments of RBC were similarly applied, compressed, and spread with a flat-surface hand instrument (Figure 9). The light beam was applied for 20 seconds after each new RBC layer was placed. After the final portion of material was applied (Figure 10), it was compressed and spread over the labial surface and then completely photo-polymerized (Figure 11).
With slow-speed diamond cylinders and aluminum oxide finishing disks, the labial surface was sculpted to recreate a natural appearance (Figure 12 and Figure 13). A fine fluted carbide finishing bur was then used to add natural enamel texture to the tooth surface (Figure 14).4 Final polishing was achieved with an extra-fine–grit polishing disk (Figure 15). Contacts with the incisal edges of the mandibular teeth were evaluated carefully in all bite excursions. Excessive contacts in protrusive and lateral mandibular positions can cause flexure of the veneered tooth or shearing forces at the incisal margin of the veneer that can dislodge the RBC. With this veneer restoration completed (Figure 16), the left central incisor was then restored in the identical manner.
At a subsequent appointment, the labial surfaces of the lateral incisors and lingual surfaces of all four incisors were saturated with Adper™ Prompt™ Self-Etch Adhesive (3M EPSE). After 20 seconds, excess adhesive was removed with a brush/applicator, and the curing light beam applied (Figure 17). The purpose was to apply a bonded resin smooth surface sealant layer that would protect the labial and lingual enamel from additional erosive damage.2,3
The patient has been seen for routine semi-annual appointments for 2 years. At 6 months, the veneers had excellent luster and color match was quite satisfactory (Figure 18). The lemon sucking habit reportedly had not continued. Flossing compliance has improved with reinstruction, but was not yet ideal. The veneers and lateral incisor surfaces have been repolished with the extra-fine aluminum oxide finishing disk at each 6 month appointment. Two years after treatment, the maxillary incisors were photographed prior to dental prophylaxis (Figure 19) and after a thorough dental cleaning and renewed polishing (Figure 20).
In the past decade, apart from the traditional hybrid-type and microfilled resins, a new group of resin composites containing nano-sized filler particles, synthesized by sol-gel and controlled sintering processes, has been introduced. These materials are marketed as offering reduced polymerization contraction, enhanced mechanical characteristics, and improved esthetics.5-8 Nanofill composites are formulated with both nanomer and nanocluster filler particles, whereas nanohybrid composites are hybrid resin composites containing finely ground glass filler and nanofiller in a prepolymerized filler form.9 Therefore, nanofills have a filler system containing predominantly nanometer-sized particles throughout the matrix, whereas nanohybrids contain nanometer-sized particles combined with more conventional filler technology.
3M ESPE introduced Filtek Supreme restorative material in 2002. In 2005, Filtek Supreme Plus Universal Restorative followed with improved shade values and brightness. Improvements in the shading system, polish retention, fluorescence, material handling, and resin and filler technology followed with Filtek Supreme Ultra Universal Restorative.
A review of available research gives a sound scientific rationale to justify choosing a nanofilled RBC for use as a direct-application labial veneer. The Filtek Supreme materials are RBCs containing nanomers composed of silica sol-gel nanofillers with a particle size range of 2 to 75 nm, and sintered zirconia/silica nanocluster with a particle size range of 0.6 to 1.4 μm.6 Filler loading is approximately 78.5% by weight. The resin matrix is composed of bis-GMA, bis-PMA, TEGDMA, and UDMA.
Evaluations of this nanofilled composite material have examined static and dynamic physical properties, wear behavior, polishability, and clinical performance. Nanofilled composites share excellent in vitro wear resistance similar to better composite resins of other types.10 With respect to material physical properties, nanofilled composites appear equivalent to best in class of other RBC classification types.11
The effect of cyclic loading on dynamic physical properties of various composite resin material types, including nanofilled and nanohybrid composites, was evaluated in a published scientific laboratory study.12 Cyclic pre-loading increased the Weibull Modulus of both Filtek Supreme Body and Filtek Supreme Translucent compared with other composites. Biaxial flexural strength of both Filtek Supreme Body and Filtek Supreme Translucent was maintained or increased after cyclic loading compared with other composites tested.
The authors of the study concluded that nanoclusters appear to provide a distinct reinforcing mechanism compared with microfill, microhybrid, or nanohybrid systems, and that silane infiltration of nanoclusters may enhance damage tolerance in the composite, with the potential for improved clinical performance.
The clinical wear performance of composite resins in posterior teeth is a critical parameter of material efficacy. The clinical wear performance of Filtek Supreme (a nanofilled composite) and Z100™ Restorative (3M ESPE) (a hybrid composite) was evaluated in posterior teeth over a 5-year period.13 The researchers found no statistical difference in volume wear between the materials, but the nanofilled composite had numerically less volumetric wear; however, the 36 to 60 month steady state vertical wear rate was statistically significantly lower for the nanofill compared with the hybrid composite (0.263 vs 0.486 μm/month, respectively).
A persistent challenge in the creation of multipurpose RBC restoratives has been the maintenance of high gloss and excellent surface polish after finishing and polishing without compromising flexural strength and material toughness. A laboratory study addressed the property of polish retention, comparing nanofilled RBC materials to conventional microhybrids.14 Results of this study indicated that all of the nanofilled composite materials had signficantly higher gloss retention (at P < .05) than any of the microhybrid materials tested. In another study, the surfaces of all materials after brushing, except those made from Filtek Z350 and Filtek Supreme, had greater roughness than unpolished surfaces and surfaces polished with either abrasive disks or silicone devices.9 These authors concluded that after brushing and polishing, nanofill resin composites made with nanoclusters demonstrated the smoothest surfaces.
Given the potential of a nanofilled composite material to maintain a high degree of surface continuity and polish, clinical evaluation of restorations in anterior teeth would be important due to the impact on esthetics. A 3-year clinical evaluation of Filtek Supreme in anterior teeth detailed the peformance of a nanofilled composite in the critical esthetic zone.15 The findings of this study at 3-year recall included no change in retention, surface staining, or secondary caries from baseline; an apparent “self-polishing” effect, as surface polish remained high; and high overall clinical performance, making it acceptable for routine clinical use.
Based on the excellent color and opacity matching of the A1B shade of Filtek Supreme Ultra, layering of material for ideal shade matching was not needed in this case. Although this brand of material has a sophisticated opacity system (enamel, dentin, body, and translucent) and an extensive array of shades, in some cases, especially in younger patients, use of the body opacity suffices.
Dr. Croll has financial interest in Strip-T matrices by virtue of a licensing agreement with Denovo Dental.
1. de Carvalho LD, Lopes GC, Maia HP, Baratieri LN. Ceramic restorations in teeth with severe acid erosion. Am J Esthet Dent. 2012;2(4):282-292.
2. Croll TP. Bonded resin sealant for smooth surface enamel defects: new concepts in “microrestorative” dentistry. Quintessence Int. 1987;18(1):5-10.
3. Croll TP. Restorative dentistry for preschool children. In: Johnson D and Tinanoff N, eds. Dental Care for the Preschool Child. Philadelphia, PA: The Dental Clinics of North America; 1995:745.
4. Croll TP. Simulating irregular enamel surface texture in composite resin restorations. Quintessence Int. 1988;19(4):311-312.
5. Moszner N, Salz U. New developments of polymeric dental composites. Prog Polym Sci. 2001;26(4):535-576.
6. Mitra SB, Wu D, Holmes BN. An application of nanotechnology in advanced dental materials. J Am Dent Assoc. 2003;134(10):1382-1390.
7. Yap AU, Tan CH, Chung SM. Wear behavior of new composite restoratives. Oper Dent. 2004;29(3):269-274.
8. Turssi CP, Ferracane JL, Serra MC. Abrasive wear of resin composites as related to finishing and polishing procedures. Dent Mater. 2005;21(7):641-648.
9. Senawongse P, Pongprueksa P. Surface roughness of nanofill and nanohybrid resin composites after polishing and brushing. J Esthet Restor Dent. 2007;19(5):265-273.
10. Turssi CP, Ferracane JL, Ferracane LL. Wear and fatigue behavior of nano-structured dental resin composites. J Biomed Mater Res B Appl Biomater. 2006;
78B:196-203.
11. Rodrigues SA Jr, Scherrer SS, Ferracane JL, Della Bona A. Microstructural characterization and fracture behavior of a microhybrid and a nanofill composite. Dent Mater. 2008;24(9):1281-1288.
12. Curtis AR, Palin WM, Fleming GJ, et al. Mechanical properties of nanofilled resin-based composites: the impact of dry and wet cyclic preloading on bi-axial flexure strength. Dent Mater. 2009;25(2):188-197.
13. Palaniappan S, Bharadwaj D, Mattar DL, et al. Nanofilled and microhybrid composite restorations: five-year clinical wear performances. Dent Mater.2011;27(7):692-700.
14. Kobussen GA, Craig BD, Halvorson RH, et al. Optical properties of an experimental highly aesthetic composite restorative [abstract 1508]. Presented at: IADR General Session; April 1-4, 2009; Miami, FL.
15. Dunn J, Munoz C, Wilson A, et al. Three year clinical evaluation of Filtek Supreme in anterior teeth [abstract 0359]. Presented at: ADEA/AADR/CADR Meeting and Exhibition; March 8-11, 2006; Orlando, FL.
Theodore P. Croll, DDS
Private Practice, Pediatric Dentistry
Doylestown, Pennsylvania
Affiliate Professor, Department of Pediatric Dentistry
University of Washington School of Dentistry
Seattle, Washington
Adjunct Professor, Pediatric Dentistry
University of Texas Health Science Center at San Antonio Dental School
San Antonio, Texas
Steven R. Jefferies, MS, DDS, PhD
Professor, Department of Restorative Dentistry
Director of Clinical Research
Kornberg School of Dentistry
Temple University
Philadelphia, Pennsylvania
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