The evaluation of intrapulpal temperature rise during the treatment of cervical dentine hypersensitivity using different laser wavelengths: in vitro

Objectives: The treatment of cervical dentine hypersensitivity using lasers with different wavelengths has been recommended in the literature. However, intrapulpal temperature rise during these treatment procedures is a major concern and there is a need for more information about the issue. The aim of this study is to evaluate the pulpal temperature rise due to laser treatment of hypersensitivity with most recommended laser wavelengths and parameters in the literature.
Methods: Twelve maxillary central incisors were sectioned 2 mm below the cemento-enamel junction and a hole was drilled through the lingual wall of pulp chamber at cingulum level to insert a J-type thermocouple wire which is in contact with the buccal wall of the chamber. The teeth were fixed on a novel apparatus simulating pulpal blood microcirculation. Laser irradiation with three different wavelengths within the following parameters were performed perpendicular to the buccal cervical area of the teeth with the nearest distance without contact: 940 nm diode laser (1W, CW, 300µm fiber), Nd:YAG laser (100mJ, 10Hz, 1W, 100µs pulse duration, 300µm fiber) and Er:Cr:YSGG laser (0.25W, 20Hz, 700µs pulse duration, 600µm fiber). Each tooth was subjected to all three wavelengths and intrapulpal temperature rise due to laser irradiation under simulated blood microcirculation conditions were real time recorded. Finally, collected data were statistically analyzed.
Results: Mean intrapulpal temperature rise in diode (5.73±1.75 °C) and Nd:YAG laser (5.04±1.40 °C) groups were comparable to each other and significantly higher than Er:Cr:YSGG (3.31±0.85 °C) group (p<0.05).
Conclusions: Within the limitations and parameters of this study, it was concluded that cervical dentine hypersensitivity treatment using Er:Cr:YSGG laser is more secure than 940 nm diode and Nd:YAG laser options with regard to pulpal temperature rise. The temperature rise in diode and Nd:YAG laser groups were about the critical level of 5.5 °C.