Does vibration improve cavity adaptation of composite resin?

This study evaluates the effect of vibration on adaptation of bulk-fill composite resin. A scanning laser doppler vibrometer measured the frequency and amplitude of a vibratory device (COMO) used for resin placement and visualized its effect on the resin according to depth. FB was placed in simulated cavities (4 mm diameter, 4 mm depth) by different layering methods (incremental filling with two 2-mm-thick layers vs. bulk filling with a single 4-mm-thick layer). The groups were further divided based on the application of vibration during restoration (no vibration vs. vibration). The voids that formed at the bottom surface of the cavity and the bottom, middle, top third, and overall void volumes were measured using micro-computed tomography. The frequency and amplitude of the COMO were approximately 149 Hz and between 26 and 51 um, respectively. Vibration provided improved surface adaptation and lower void volumes during incremental filling ( p   0.05). Void volume was markedly higher in the bottom part in all groups. Application of vibration to the resin with a 2-mm incremental-layering technique produced the best adaptation of the composite resin.