Temperature changes of pulpal chamber and infrared-blocking bleaching gel activated with halogen light

Purpose: To evaluate temperature changes of pulpal chamber (PC) and infrared blocking bleaching gel on dental surface (SUR) during the activation with photocuring units with halogen lights that emit radiation in the infrared (IR) range. Methods: The bleaching gels Whiteness HP Maxx (IR-blocker - MX) and Whiteness HP (control - CON) were used in ten maxillary central incisors. Light-activation was performed by using the photocuring units (FC) Optilight (600mW/cm2, OP) or Jet Lite (1200mW/cm2, JL) with four 40s-activation procedures with no interval (total time: 3min 20s). The temperature was measured each 40s using a digital thermometer with two type K thermocouples placed inside the PC and on dental surface (SUR). Data were analyzed with 3-way ANOVA (gel type - GT, FC and activation time) and Tukey's test. Results: A significant effect was found for the main factors FC and GT, and for their interaction. The means (SD) (in Celsius degree) were: PC:[GT={MX-6,38(3,25)a, CON-7,70(2,91)b}, FC={OP-5,51(2,54)a, JL-8,56(2,93)b}]; SUR: [GT={CON-9,85(3,89)a, MX-14,21(7,76)b}, FC={OP-7,32(2,50)a, JL-16,74(5,82)b}]. Conclusions: MX resulted in lower pulp chamber heating and higher gel heating than the control group. JL promoted greater heating than OP.