In vivo evaluation of the surface of posterior resin composite restorations: A pilot study

Statement of problem. Several methods have been used to determine the surfa ce characteristics of resin composites in vivo and compare composite wear r ates with enamel wear rates. Purpose. This pilot study describes the surface characteristics of resin co mposites and the wear Of resin composites and enamel during 1 year of in vi vo service. Material and methods. A single Class II posterior resin composite restorati on (Z100) was placed in 10 patients. Restored teeth and unrestored adjacent control teeth were measured for wear 4 times within the first year. A null point contact stylus profiler and fitting software were used to measure ep oxy casts. Maximum depth of wear, average depth of wear, and characteristic s of the restoration margin were determined. Paired t tests were used to co mpare the control and restored teeth, and ANOVA was used to assess the prog ression of wear over time (P<.05). Results, After 1 year, maximum depth of wear over the entire preparation re gion was on average 204.8 mu m (+/- 129.8), significantly greater than the 36.8 mu m (+/- 10.1) average maximum depth of wear of enamel at occlusal co ntact areas on control teeth (P=.009). Maximum depth of wear progressed ove r time (P=.009). Fracture of excess composite, commonly called flash fractu re, occurred in 50% of the restored teeth extending over the preparation ma rgin. Conclusion, Composite restorations wore significantly faster than enamel co ntact areas on control teeth. Also of concern were thr marginal flash fract ures that could facilitate secondary caries.