Methods: The present study evaluated intrapulpal temperature changes of 15 extracted human teeth, induced by the application of various thermal stimuli to their external surface. For this purpose a new in vitro model that allowed the circulation of 37ºC distilled water inside pulp chamber, was used. Intrapulpal temperature rises were induced by applying, firstly, a specially modified thermode to the tested teeth. Furthermore, the same model was used in order to measure intrapulpal temperature rise during light activated bleaching. Light curing units used were a conventional halogen (Group A) two high intensity halogen lamps (Group B & Group C), a plasma arc curing light (Group D), a mercury metal halide light (Group E) and a diode laser (Group F).
Results: Statistical analysis, during the first part of this study, revealed that the average temperature rise within pulp chamber was 12.6ºC, 11, 5ºC and 28ºC without water flow for the canines, central incisors and lateral incisors respectively. The mean values with water flow were 2.5ºC, 6.1ºC and 13ºC respectively. During bleaching testing maximum temperature changes varied significantly: 0-6ºC (Group A), 0-15ºC (Group B), 0-19ºC (Group C), 0-8ºC (Group D), 0-10ºC (Group E), 0-39ºC (Group F).
Conclusion: The present study strongly indicates that simulation of pulpal microcirculation in vitro significantly influences the temperature rise within the pulp chamber.