Thermal and Morphological Effects of the Pulsed Nd:YAG Laser on Root Canal Surfaces

Abstract Objective: To investigate the sequential thermal and morphological effects of the pulsed Nd:YAG laser on root canal surfaces. Background Data: Effectiveness and safety are two critical aspects of laser application for root canal instrumentation. To date, few studies have synchronously focused on the efficacy of root canal cleanliness and thermal changes in root surfaces irradiated by the Nd:YAG laser. Materials and Methods: Single-root human premolars (n = 144) were sectioned at the cementoenamel junction. The root canals were instrumented and divided into three groups: group 1 (15 Hz), group 2 (20 Hz), and group 3 (15 Hz with black ink). Each group was divided into eight subgroups according to the laser power settings used. The temperature elevations of the apical and coronal root surfaces were measured with a thermocouple measurement system during laser irradiation. Then the roots were bisected longitudinally and examined with the scanning electron microscope. Results: There was a positive corr...