In vitro wear of various orthotic device materials

Statement of problem. Orthotic devices are advocated to decrease occlusal attrition caused by bruxism but tend to wear with time. Purpose. This study investigated the wear rate of various materials used to fabricate orthotic devices. Material and methods. Five experimental groups (n=8) were studied: Splint Biocryl autopolymerized (SBA), Splint Biocryl autopolymerized plus additional heat and pressure (SBHP), Forestacryl autopolymerized (FA), Forestacryl autopolymerized plus additional heat and pressure (FHP), and Quick Splint 15-minute (QS), light-polymerized composite. Specimens were mounted to the base of a universal testing machine. A wear device using steatite balls and a load of 9.1 kg was positioned against the specimens, submerged in a 37°C water bath and subjected to 2500 reciprocal cycles. Wear, in micrometers, was calculated as the maximum peak to valley measurement (R_y) using profilometry. Data were subjected to analysis of variance (ANOVA) and Tukey's HSD (α=.05). Results. Mean acrylic wear in micrometers was as follows: FA 6.8 ±3.0; FHP 7.1 ± 1.8; SBA 20.4 ± 5.6; SBHP 23.7 ± 7.8; and QS 23.8 ± 6.9. One-way ANOVA detected significant differences between groups (P<.001); the Tukey honestly significant difference test determined that FA and FHP specimens were significantly more resistant to wear than all other specimens (P=.007). Conclusion. Differences in in vitro wear resistance among various orthotic device materials exist. The in vitro wear resistance among other autopolymerizing materials appears to be related to proprietary differences.