An Assessment of Restoration Microleakage In Vitro Following Three-Body Wear

This study assessed the microleakage of different intracoronal restorations (100 teeth). The teeth were restored using either a porcelain inlay or an amalgam restoration. The porcelain inlays were placed with one of two composite resins (Scotchbond Multi-Purpose Plus, 3M, resin A: Nexus Universal Luting System, Kerr, resin B). The amalgam restorations were placed either with one of the two composite resins or, without any resin. All restorations were subject to one of two wear cycles. These were a tooth-restoration-tooth wear cycle or a restoration-tooth wear cycle. Measurements of microleakage were made every 5,000 cycles of wear for 25,000 cycles using a microleakage model developed by Pashley (Derkson et al., 1986). The results were analysed using two-sample t-tests, one-way analysis of variance (ANOVA) to determine the presence of any differences between groups and Tukey tests to determine the nature of such differences where appropriate. 1. The results indicated that micro leakage increased with increasing exposure to wear cycles. 2. Amalgam restorations with no resin leaked more than amalgam restorations placed with resin. 3. Surprisingly porcelain resin restorations exhibited greater levels of micro leakage than amalgam restorations, with or without resin. 4. There were no statistically significant differences between the resin bonding systems used in the study. In conclusion this model has demonstrated increased microleakage with increased wear for a number of different restoration types. However, improved specimen grouping prior to exposure to different wear cycles would have made differences between restorations more meaningful. Further work should address this problem