In vitro studies the influence of Nd: YAG laser on dental enamels.

Abstract

The present work aimed at assessing chemical, topographical, and morphological changes induced by Nd : YAG laser treatment of dental enamels by means of energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and scanning electron microscopy (SEM). Fifteen human enamel specimens were obtained, three of samples were kept untreated as a control while the others twelve samples were equally divided into four groups where each group have a three samples according to treating approach as: G1:(untreated);G2: (treated with Nd:YAG laser, 100mJ/pulse,10Hz/1064nm); G3(treated with Nd:YAG laser, 500mJ/pulse, 10Hz/1064nm); G4(treated with Nd:YAG laser 1000mJ/pulse, 10Hz/1064nm), and finally G5(treated with Nd:YAG laser, 1000mJ/pulse, 10Hz/532nm) respectively. Beside many craters and cracks, the AFM results showed fractures with depths of 19.23nm, 174.7nm, 216.9nm, 207.4nm and 156.5nm and width of 559.2nm, 833.4nm, 1115nm, 695.0nm, and 5142nm for all Groups respectively. The highest surface roughness was found in G5 with 111.4nm while the lowest surface roughness was found in G1 to be 14.3nm. The inside surface of the fissures was also rough. The SEM micrographs revealed modifications to the morphology. EDS was used to measure the phosphorous (P), calcium (Ca), oxygen (O), and carbon (C) percentages presented in crater areas and their surroundings, Ca, P, O, and C levels were observed to vary significantly at the crater and its rim, a lower percentage of C wt% were realized corresponding to laser treatment of 1000mJ/Pulse laser energy. However, it was not feasible to recognize a specific chemical arrangement in the craters. It is also concluded that the higher depth and particular edge of ablated part when teeth were irradiated by laser with 1000mJ/10Hz/1064nm.