Evaluation of Cuspal Deflection of Fiber Reinforcing Composite Application Techniques Using Measuroscope

: Objective: To evaluate cuspal deflection of mesio-occluso-distal (MOD) cavities restored with short fiber-reinforced composite. Materials and Methods: Two different commercially available composite resin restorations; short fiber-reinforced (ever X Posterior GC, Tokyo Japan) and conventional micro-hybrid (G-aenial universal resin composite GC, Tokyo Japan) resin composite restorative material bonded with a universal adhesive (G-Premio BOND GC, Tokyo Japan) were used in the current study. A total of 40 sound maxillary human premolars were selected for the cuspal deflection test and received standardized MOD cavity preparations suitable for each test. The sample was divided into four groups; Group A: conventional microhybrid resin composite (conv.), Group B: short fiber-reinforced composite (SFRCs), Group C: short fiber-reinforced composite laminated with conventional microhybrid resin composite (SFRCs+conv.), Group D: short fiber-reinforced composite "cut off" then laminated with conventional microhybrid resin composite. Measuroscope was used to evaluate the cuspal deflection. For the cuspal deflection test, the collected data from each test were tabulated, coded and then statistically analyzed. One-way ANOVA followed by a post-hoc Tukey test was used for multiple comparisons. The level of significance was set at P < 0.05. Results: Both Group A (conv.) and Group C (SFRCs+conv.) showed insignificant differences in cuspal deflection values, in comparison with groups B ( SFRCS) and D (Cut off) (p > 0.05). There were significant differences in cuspal deflection between Group A (conv.) and group c (SFRCs+conv.) (p < 0.05). There were significant differences in cuspal deflection between groups, B( SFRCS) and group D (Cut off) (p < 0.05). Conclusions: Conventional resin composites exhibit higher cuspal deflection values than those containing short fibers. Laminating conventional resin composite to SFRCS, as per the manufacturer's instructions, increases cuspal deflection values more than SFRCS. The cut-off technique seems to have a positive effect on the cuspal deflection value.