Effect of Polishing Techniques and the Resistance to Stain of Universal Dental Composites

Composite resins are dental restorative materials that have superior esthetic properties, with "Universal" composites claiming one-type-suits-all shade matching ability to most tooth shades. Although esthetically desirable, composites are susceptible to staining by external factors (e.g.: coffee, tea, red wine, smoking, etc.). Excessive staining may generate patient dissatisfaction and the desire to replace the restoration, regardless of disease status, resulting in unnecessary dental restorative procedures. Objective: (1) To compare the staining of two universal and one shade-based(control) composites using spectrophotometry and visual shade matching after 1 year of simulated exposure to coffee, and (2) To evaluate the effect of finishing and polishing protocols on stain prevention. Methods: Thirty composite disc samples (3mm x 10mm) were made for each composite: Ten were cured with clear Mylar matrix strip, ten finished and polished with Sof-Lex Discs and ten finished and polished with Enhance/PoGo System. The samples were incubated in deionized water at 37 deg for 24 hrs to maximize polymerization. Initial shades were measured with a spectrophotometer and confirmed by VITA Classical Shade Guide tabs. All samples were submersed in coffee solution for 15 days, simulating one year of coffee staining, and final shades were measured. Results: There was no significant difference in shade value, post exposure to coffee, amongst the three unpolished composites. However, Control and Universal Type I samples finished to semi-gloss status using the Sof-Lex system were less likely to stain(comparing values D4 vs. C4) compared to matte-finished Universal Type II samples utilizing Sof-Lex or PoGo systems (p<0.05). Conclusions: Universal composites claim to have several advantages over shade-based composites. Without finishing/polishing, universal composites perform similar to shade-based composites in stain resistance.