Analysis of thermal profiles on tooth structure and insert during one-piece or adapter-coupled ultrasonic insert use: an in vitro experimental study.

Objectives: This in vitro study aimed to evaluate temperature variation on the external surface of mandibular molars and within ultrasonic inserts when using adapter-coupled versus one-piece inserts. Methods: Twenty-four extracted human mandibular molars were divided into two groups based on the type of ultrasonic insert used: adapter-coupled and one-piece inserts. Temperature on the external surface of each tooth was measured with a thermocouple probe positioned in the furcation area, capturing data continuously. The temperature of the ultrasonic inserts was monitored in real-time using a thermal imaging camera. Measurements were taken in a controlled environment without cooling for over 120 seconds. Statistical analysis was conducted using analysis of variance (ANOVA) and two-way ANOVA with repeated measures to evaluate temperature variations between groups and over time, with significance set at 5%. Results: In the external tooth surface temperature measurements, no significant differences were observed between the groups during the initial 15 seconds (p = 0.185) and 30 seconds (p = 0.067). However, significant differences emerged at 60 seconds (p = 0.025), 90 seconds (p = 0.024), and 120 seconds (p = 0.020), with the one-piece insert group demonstrating higher temperatures in the furcation region. Thermal imaging of the inserts revealed a significant difference at all time points (p < 0.001), with adapter-coupled inserts showing greater heating. Conclusions: The use of ultrasonic inserts leads to a gradual rise in temperature on the external tooth surface. One-piece inserts generated higher temperatures on the tooth, while adapter-coupled inserts exhibited greater heating within the insert.