Evaluation of surface roughness of enamel after laser irradiation

Polishing enamel is a dental procedure that involves a rotating brush to remove surface stains and smooth any rough areas on the teeth. Laser technology has been tested in all dentistry fields to enhance the quality of the treatment. The aim of this study is to define the optimum parameters for laser power and irradiation time in decreasing the roughness of the enamel and having a smooth, healthy surface in a long-term prognosis using a new wavelength in a dental era, 1940-nm Thulium Fiber Laser (TLR-5-1940; IPG Laser GmbH, Germany). After preparing teeth samples, preliminary experiments were done by a laser and thermal camera set-up while applying different lasing powers varying between (0.25 W and 5 W) and an irradiation time from (1 sec to 12 sec), which produced energy from (0.25J to, 15 J). The main experiments were performed using Hirox 3D microscope to determine parameters' effects. The areas for both pre and post lasing surfaces were graphed, the differences in values were examined and compared. In the main experiment, irradiating a total of 3 joules energy on the enamel surface showed non-significant differences between the area under the curve of before-lasing and after-lasing enamel surface area were not significantly different. On the record 0.75 Watt was the most promising parameter which resulted in a decrease in the surface area while other parameters showed an increase in enamel surface roughness. By applying laser powers from 0.25 Watts to 5.0 Watts showed no carbonization effect or observable cracks under microscope.