Effect of Rinsing Water Temperature on Microleakage of Dental Composite Restorations: An In-Vitro Study

Objectives: This study assessed the impact of rinsing water temperature on microleakage of dental composite restorations. Materials and Methods: This in vitro study was conducted on 72 extracted premolars. Buccal and lingual Class V cavities were prepared with gingival margins 1mm beneath the cementoenamel junction (CEJ) and occlusal margins 2mm above the CEJ. The specimens were classified into three groups (n=24) for rinsing with water at 23°C, 4°C, and 45°C before the bonding procedure. Lingual cavities were bonded with a self-etch adhesive, and buccal cavities were bonded with a total-etch adhesive. After composite restoration, the specimens underwent 1000 thermal cycles between 5-55°C. They were then divided into two groups for storage for either 24 hours or 2 months. Optical and electron microscopic assessments were performed to score microleakage at the occlusal and gingival margins of the specimens. The Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests were run to analyze the data (alpha=0.05). Results: Regardless of the bonding system and storage time, microleakage was significantly higher in the 4°C rinsing water group (P<0.05). Gingival margins bonded with the total-etch adhesive had a significantly higher microleakage than the occlusal margins in both 23°C and 45°C groups (P<0.05), but the self-etch adhesive showed no significant difference (P>0.05). Conclusion: According to the results of this in vitro study, rinsing the cavity with warm water (23°C and 45°C) appears to be an effective method to reduce the rate of microleakage.