Faculty Bibliography

Resin-based composites are increasingly used for the restoration of defects in posterior teeth. This review describes, illustrates and discusses important clinical aspects of the posterior composite technique. A relatively new stratification concept oriented to the development of functional and anatomic restorations is proposed.

The purpose of this study was to evaluate the effects of phosphoric acid (PA) and a proprietary glutaraldehyde-HEMA aqueous solution (Gluma Desensitizer; GD) on dentin collagen. Specimens of demineralized bovine dentin collagen were treated with either 37% or 50% PA for 1 or 5 min. An additional set of specimens was treated with 37% PA for 1 min followed by GD for 1 min. All specimens were washed with distilled water, lyophilized. reduced with standardized NaB3H4, hydrolyzed with 6 M HCl and subjected to amino acid and cross-link analyses. The results demonstrated that the treatment of demineralized dentin with PA under the conditions tested did not significantly alter the collagen cross-links. The GD-treated samples showed reduction of free lysine (Lys) and hydroxylysine (Hyl) residues, as well as a decrease in the levels of collagen reducible cross-links. In addition, unidentified reducible compounds were detected by high-performance liquid chromatography (HPLC) analysis. These compounds may be derived from cross-links formed between GD-derived aldehyde and Lys/Hyl of collagen. The findings indicate that PA treatment does not significantly affect dentin collagen amino acid and cross-link composition, and that GD treatment affects dentin collagen amino acid and cross-link composition.

PURPOSE/OBJECTIVE:To evaluate the effect of the inclusion of glutaraldehyde on the shear bond strength of new ethanol-based adhesives (Gluma Comfort Bond & Desensitizer, GCBD and Gluma Comfort Bond, GCB) versus acetone-based Gluma One Bond (GOB) and a conventional three-step adhesive as a control. MATERIALS AND METHODS/METHODS:Forty bovine incisors were mounted in acrylic, polished to 600-grit, and randomly assigned to four groups (n=10). Dentin was etched for 15 s using 35% phosphoric acid, rinsed, and lightly dried. After adhesive application and curing, Charisma composite was applied in a #5 gelatin capsule and light-cured. Specimens were loaded in shear using an Instron at 5 mm/min. Shear bond strengths were calculated by dividing failure load by bonded surface area. ANOVA showed a significant difference in means at P< 0.01, so Tukey's test was used for pairwise comparisons. RESULTS:Mean SBS (+/- SD, MPa) were: GOB: 8 (4.4)ab; GCB: 10 (4.4)ab; GCBD: 14 (6)bc; SBMP: 17.7 (6.4)c. Superscript letters indicate Tukey's homogeneous subsets (P< 0.05).

PURPOSE/OBJECTIVE:To report the 4-year clinical performance of posterior resin-based composite restorations placed using the total-etch technique. MATERIALS AND METHODS/METHODS:Over a period of 1 year, 726 restorations (248 molars, 478 premolars; 260 Class I, 466 Class II; 540 replacements, 186 primary decay) were placed on conservative preparations, using the incremental placement technique in a clinical environment. Baseline data were collected, and the restorations were evaluated after 4 years. Z100 and Scotchbond Multi-Purpose (SBMP) (3M Dental Products, St. Paul, Minnesota) were used as the restorative system. The criteria evaluated were color match, marginal adaptation, anatomic form, cavosurface marginal discoloration, axial contour, interproximal contact, secondary caries, postoperative sensitivity, and tooth vitality. RESULTS:At baseline, 24% of the teeth restored presented postoperative sensitivity; 86% of the sensitive teeth were from the replacement group. At 4 years, all teeth were vital to cold test. Eighteen restorations (2.5%) presented clinically detectable marginal fracture. The shade was acceptable in all restorations. Cavosurface marginal discoloration was observed in 47 restorations (6.5% bravo scores). Axial contour, interproximal contact, and marginal adaptation received 100% alfa scores. No secondary caries was diagnosed in any of the teeth examined. None of the examined restorations required replacement. CLINICAL SIGNIFICANCE/CONCLUSIONS:Under controlled clinical conditions, posterior resin-based composite restorations placed with the total-etch technique and restorative Z100/SBMP have the potential to present a high success rate at 4 years. None of the examined restorations required replacement, and there was no clinically detectable wear in any of the restorations. Simultaneous etching of enamel and dentin followed by the application of a resin adhesive can be considered an adequate modality of pulp protection in nonexposed tooth preparations.