MICROLEAKAGE OF CLASS-5 COMPOSITE RESIN RESTORATIONS - A COMPARISON BETWEEN IN-VIVO AND IN-VITRO

The purpose of this study was to determine if a difference exists in m icroleakage between in vivo and in vitro class 5 composite resin resto rations using two variations of a bonding resin (Universal Bond 2 and Universal Bond 3). Class 5 cavities were prepared In 24 matched pairs of teeth on the buccal and lingual surfaces. One tooth of each pair wa s prepared and restored in vivo and the other in vitro. After preparat ion and enamel etching, Universal Bond 2 was randomly applied to one s urface of each tooth in the pair and Universal Bond 3 to the other sur face. Composite resin (Prisma AP.H) was placed in each preparation, li ght cured, and finished using a standard technique. The in vivo sample s were extracted approximately 6 weeks after placement of the restorat ions. The in vitro samples were thermocycled for 540 cycles (5 to 55-d egrees-C/1-minute dwell time). All teeth were stained with silver nitr ate and longitudinally divided. The teeth were scored on a ranking sys tem of 0 being no leakage to 4 being leakage to the pulpal wall of the preparation. A Wilcoxon matched pairs signed rank test was performed on the data (P less-than-or-equal-to 0.05). There were no statisticall y significant differences in microleakage between restorations using U niversal Bond 2 and Universal Bond 3. There were statistically signifi cant differences when comparing the in vivo and in vitro restorations. More microleakage occurred in the In vitro restorations.