The effect of temperature of sodium hypochlorite on fracture resistance of endodontically treated teeth - An in vitro study.

Context: Sodium hypochlorite (NaOCl) is commonly used in endodontics for its strong antimicrobial properties, with heating enhancing its reactivity and ability to dissolve organic matter. Cryo-treated hypochlorite, however, can help reduce postendodontic pain. The chemical composition and temperature of irrigants play a key role in influencing the tooth structure's physical properties, potentially affecting treatment outcomes.

Aims: The study aims to evaluate the effect of various temperatures of NaOCl which is 60°C, 45°C, 25°C, and 2°C on the fracture resistance of endodontically treated teeth.

Subjects and methods: After the selection of 40 single-rooted teeth, the decoronation, and chemomechanical preparation was done, and the teeth were randomly assigned into four groups (n = 10 in each group) based on the final temperature of NaOCl. Group I at 60°C, Group II at 45°C, Group III at 2°C, and Group IV (control) at 25°C. The teeth were then tested for fracture resistance using a universal testing machine with a crosshead speed of 1 mm/min.

Statistical analysis used: One-way ANOVA and post hoc Tukey's tests were used.

Results: Group II (45°C) exhibited significantly higher fracture resistance compared to all other groups (P < 0.001), followed by Group III (2°C) and Group IV (25°C), whereas Group I (60°C) demonstrated the lowest fracture resistance.

Conclusions: For optimal effectiveness, it is recommended to irrigate with NaOCl at a temperature of 45°C. This ensures enhanced antimicrobial activity. In addition, this temperature helps maintain the integrity of the endodontically treated teeth.