The Influence of Sonic Activated Bulk Fill Packing Technique on the Fracture Resistance of Mod Resin Composite Restorations: A Comparative in Vitro Study

Aim: This study aimed to evaluate impact of sonic activation bulk placement technique on the fracture resistance of Mesio-occluso-distal resin composite restorations, in contrast to the conventional bulk placement technique. Materials & Methods: Sixty maxillary premolars were allocated into six groups, with each group including ten premolars (n=10) (A). Groups (A1&A2) were utilized as positive controls and were not subjected to cavity preparation. Mesio-occluso-distal cavities were formed in the remaining 40 premolars. Afterwards, these cavities were divided into four groups of comparable magnitude. Groups (A3&A4) were restored using a sonic activated bulk fill resin composite. Conversely, groups (A5&A6) were repaired using Tetric N-Ceram Bulk Fill resin composite. Every sample was subjected to thermal load cycling using a chewing simulator device called ROBOTA in order to recreate circumstances seen in the mouth. 50% of the specimens were subjected to 417 cycles, which imitated a 24-hour loading period, while the remaining 50% underwent 75,000 cycles, which represented a 6-month loading period. The specimens underwent compressive axial stress until they shattered, utilizing an Instron Universal Testing Machine. The data was subjected to statistical analysis. Results: There was no noticeable difference detected among the groups assessed after 24 hours of loading. Following a 6-month period of load cycling, the control group displayed the highest average values, which did not show any significant difference compared to the sonic fill group. Conclusions: The Sonic Fill™ composite is a feasible treatment option that can improve the structural strength of deficient maxillary premolar teeth.