Faculty Bibliography

This study evaluated the effect of the elastic modulus and margin configuration on the clinical performance of resin-based composite restorations in Class V non-carious defects. One hundred and five cervical non-carious defects on buccal surfaces of canines and premolars were included in this study. Defects were randomly divided into three Groups and restored according to the following techniques: Group 1--no enamel bevel was placed and the defect was restored with a microfilled resin-based composite (Durafill VS); Group 2--the enamel margin was beveled and the defect restored as in Group 1; Group 3-the enamel margin was beveled and the defect was restored with a flowable resin-based composite (Natural Flow). Each group comprised 35 lesions. A total-etch, one-bottle adhesive (One-Step) was used in all groups. Retention rate, pre- and post-operative sensitivity, marginal discoloration and secondary caries were determined over a three-year period and the data were analyzed statistically. At six months post-insertion, the restorations placed with beveled enamel margins resulted in 100% retention regardless of the composite used compared to a 66% retention of the non-beveled margins. At two and three years, no significant difference in retention rate was found among the three groups. Post-operative sensitivity, marginal discoloration and secondary caries were not affected by enamel beveling and restorative material. Beveled enamel margins resulted in significantly better clinical retention in the first six months only. Enamel beveling and composite viscosity appeared to not significantly affect the clinical performance of Class V non-retentive composite restorations after three years.

PURPOSE/OBJECTIVE:To compare the repair potential of a packable composite (Filtek P60) to that of a conventional hybrid composite (Pertac II) using three different adhesives: an unfilled resin (EBS-Multi), a one-bottle, acetone-based adhesive (One-Step), and a self-etching adhesive (Prompt L-Pop). MATERIALS AND METHODS/METHODS:30 composite disks (diameter = 8 mm) of each composite material were fabricated, light-cured, and stored in 37 degrees C for 7 days. The specimens were polished to 600-grit, sandblasted (CoJet-System), silanated, and randomly assigned to three groups (n=10). EBS-Multi, One-Step, and Prompt L-Pop were applied to each composite and cured. Pertac II was applied in a #5 gelatin capsule and light-cured. As controls, Pertac II was applied to freshly cured Filtek P60 and Pertac II specimens, with no additional surface treatment. Specimens were loaded in shear using an Instron testing machine at a crosshead speed of 5 mm/minute, 24 hours after bonding, and the peak shear force at failure was converted to MPa (force/area). RESULTS:ANOVA showed a significant difference in means at P<0.001. Tukey's test was used for pairwise comparisons. Mean SBS (+/-SD, MPa) were: P60/control: 25.2 (3.0); P60/EBS-Multi: 18.0 (2.3); P60/One-Step: 16.7 (2.3); P60/Prompt: 10.5 (3.3); Pertac/control: 25.5 (3.6); Pertac/EBS-Multi: 18.8 (3.0); Pertac/One-Step: 18.8 (2.4); Pertac/Prompt: 9.7 (3.5). Repair strengths were all significantly less than their respective controls, and repairs made using Prompt L-Pop had significantly lower mean strengths than the repairs made with EBS-Multi and One-Step (P<0.05).

The purpose of this study was to evaluate the influence of calcium hydroxide (Ca(OH)2) treatment on the bond strengths to dentin of a resin-based composite material. Two distinct dental adhesives, Prime & Bond (P&B) NT and Single Bond (SB) were used. One hundred and twenty-seven bovine incisors were mounted in acrylic, ground flat to expose middle dentin, polished to 600-grit, and randomly assigned to 10 groups: (i) 0 days, no Ca(OH)2, P&B NT; (ii) 7 days, no Ca(OH)2, P&B NT; (iii) 7 days, Ca(OH)2, P&B NT; (iv) 30 days, no Ca(OH)2, P&B NT; (v) 30 days, Ca(OH)2, P&B NT; (vi) 0 days, no Ca(OH)2, SB; (vii) 7 days, no Ca(OH)2, SB; (viii) 7 days, Ca(OH)2, SB; (ix) 30 days, no Ca(OH)2, SB; (x) 30 days, Ca(OH)2, SB. All specimens were stored in an incubator at 37 degrees C. Specimens were then retrieved and the dentin surface was rinsed with air/water spray from a triple syringe. Dentin was etched with 37% phosphoric acid (PA) for 15 s, rinsed, blot dried, and coated with adhesive according to manufacturer's instructions. The adhesive was light cured for 10 s, and Filtek Z250 was applied to the surface with a #5 gelatin capsule and light cured for 160 s. Shear bond strengths were measured for each specimen in an Instron unit at a cross-head speed of 0.5 mm min(-1). The data were subjected to anova and Duncan post-hoc tests. Mean shear bond strengths for P&B NT ranged from 8.02 to 11.79 MPa. There was no significant difference between P&B NT groups treated with or without Ca(OH)2 at any time interval. Mean shear bond strengths for SB ranged from 14.70 to 19.54 MPa. No significant difference was found between SB groups treated with or without Ca(OH)2 at 7 days. At 30 days, SB with Ca(OH)2 was significantly higher than SB without Ca(OH)2. Short-term Ca(OH)2 treatment had no detrimental effect on dentin bond strengths to the ethanol or acetone-based adhesive resin systems tested.