Effect of different stripping techniques on pulpal temperature: in vitro study

ABSTRACT Introduction: Proximal stripping of enamel is a routine clinical procedure employed in orthodontics to create space or for balancing tooth size discrepancies. This procedure may result in heat transfer to the pulp, predisposing it to histopathological changes and necrosis of the pulp tissue. Objective: To measure the temperature changes in the pulp chamber during different stripping procedures. Methods: 80 proximal surfaces of 40 extracted human premolar teeth were stripped using four techniques: diamond burs in air-rotor handpiece with air-water spray; diamond burs in micromotor handpiece, with and without a coolant spray; and hand-held diamond strips. A J-type thermocouple connected to a digital thermometer was inserted into the pulp chamber for evaluation of temperature during the stripping procedure. Results: An increase in the pulpal temperature was observed for all stripping method. Diamond burs in micromotor handpiece without coolant resulted in the higher increase in temperature (3.5oC), followed by hand-held diamond strips (2.8oC), diamond burs in air-rotor with air-water spray (1.9oC); and the smallest increase was seen with diamond burs in micromotor handpiece with coolant (1.65oC). None of the techniques resulted in temperature increase above the critical level of 5.5oC. Conclusion: Frictional heat produced with different stripping techniques results in increase in the pulpal temperature, therefore, caution is advised during this procedure. A coolant spray can limit the increase in temperature of the pulp.

摘要
引言：牙釉质邻面去釉是正畸临床中用于开辟间隙或平衡牙量不调的常规操作。该操作可能导致热量传导至牙髓，使其易发生组织病理学改变及牙髓组织坏死。
研究目的：本研究旨在测量不同去釉操作过程中牙髓腔的温度变化。
方法：选取40颗已拔除的人前磨牙，对其80个邻面分别采用4种技术进行去釉处理：① 气动手机搭载金刚砂车针并辅以气水喷雾；② 带冷却喷雾的微型马达手机搭载金刚砂车针；③ 无冷却喷雾的微型马达手机搭载金刚砂车针；④ 手持金刚砂条。将连接于数字温度计的J型热电偶（J-type thermocouple）插入牙髓腔，以评估去釉过程中的温度变化。
结果：所有去釉方法均导致牙髓温度升高。其中，无冷却喷雾的微型马达手机金刚砂车针技术温度升高幅度最大（3.5℃），其次为手持金刚砂条技术（2.8℃），辅以气水喷雾的气动手机金刚砂车针技术（1.9℃），而带冷却喷雾的微型马达手机金刚砂车针技术温度升高幅度最小（1.65℃）。所有技术均未使温度升高超过临界值5.5℃。
结论：不同去釉技术产生的摩擦热均会导致牙髓温度升高，因此该操作过程中需谨慎行事。冷却喷雾可有效限制牙髓温度的升高。