Cuspal Deflection in Premolar Teeth Restored with Bulk-Fill Resin-Based Composite Materials

Objectives: The present study investigated the effect of three high viscosity bulk-fill resin-based composite materials on cuspal deflection in premolar teeth
Methods: Thirty-two sound maxillary premolar teeth with large slot MOD cavities were distributed to four groups (n=8). Groups A, B, and C were restored with bulk-fill resin composite materials (Tetric EvoCeram, X-tra fil, and Sonic Fill, respectively) in a single increment. In group D (control group) (Filtek Z100, 3M ESPE), the cavities was restored in 2mm increments. Cusp deflection was recorded post irradiation using Nikon measurescope UM-2 (Nikon, Tokyo, Japan), by measuring the changes in the bucco-palatal width of the premolar teeth at 5 minutes, 24 hours, and 48hours after completion of the restoration. The cuspal deflection was obtained by recording the difference between the baseline measurements and the other measurements for each tooth.
Results: Cuspal deflection is significantly higher in Conventional Composite than in Tetric EvoCeram Bulk Fill (p=0.0031), X-tra Fil Bulk (p=0.0029), and SonicFill Bulk (p=0.0002). There is no significant difference in cuspal deflection for Tetric EvoCeram Bulk, X-tra Fil Bulk, and SonicFill Bulk Composites.
Conclusions:
Within the limits of this in-vitro study,
● Cuspal deflection were less in teeth restored with high viscosity bulk-fill resin composites than teeth filled with a conventional incrementally placed resin composite,
● different high viscosity bulk-fill resin composites result in similar amounts of cuspal deflection, and
● complete recovery of the cusps to an original position does not occur during a 48 hour-period.