Does preheating affect the microleakage of bulk-fill composite restorations?

Aim: Microleakage is one of the most important factors in restoration failure in today’s dentistry. The aim of this in vitro study is to evaluate the microleakage of preheated bulk-fill composites. Methodology: In the study, 160 slot cavities prepared in the mesial and distal of 80 molar teeth were used. In the gingival of the cavities, Estelite Bulk Fill Flow (Tokuyama, Tokyo, Japan) in the mesial and SDR® Posterior Bulk Fill Flowable Base (Dentsply, DeTrey, Konstanz, Germany) in the distal were used, and the remaining occlusal parts were restored using FiltekTM One Bulk Fill Restorative (3M, St Paul, MN, US). Composites were applied at four different temperatures (4oC, room temperature, 39oC and 55oC). After finishing and polishing, specimens were thermocycled and then placed in 0.5% methylene blue for 24 hours. Specimens were sectioned into two parts in a mesiodistal direction, and the microleakage levels were examined by a stereomicroscope (x40). Results: In the statistical evaluation of the microleakage levels of FiltekTM One Bulk Fill Restorative applied at four different temperatures on the occlusal surface with One-way ANOVA, it was observed that there was a significant difference between the groups (p=0.02). In the comparison of the microleakage values of Estelite Bulk Fill Flow applied in the gingival region with the one-way ANOVA test at four different temperatures, there was no statistically significant difference between the groups (p>0.05), while there was a significant difference between the groups using SDR® Posterior Bulk Fill Flowable Base (p=0.002). The highest microleakage values were observed at 4oC in all groups. Conclusion: The results obtained in the study show that heating bulk fill composites before polymerization is effective in reducing microleakages, but longer in vivo studies are required. How to cite this article: Aktuğ Karademir S, Akarsu S. Does preheating affect the microleakage of bulk fill composite restorations?. Int Dent Res 2024;14(2):84-92. https://doi.org/10.5577/intdentres.481