Comparison of microhardness and micromorphology of enamel following a fissurotomy procedure using three different laser systems: An in vitro study

Aim: To compare the microhardness and microstructural changes induced in pits and fissure following a fissurotomy procedure using three different light amplification by stimulated emission of radiation (LASER) systems. Materials and Methods: Thirty caries free premolars, extracted atraumatically for orthodontic treatment were included in the study. Using a diamond low-speed disc, enamel blocks containing the pits and fissure were cut from the tooth and divided into three groups containing 10 samples in each (G1 - diode, G2 - carbon dioxide [CO 2 ], and G3 - erbium). The enamel blocks were mounted using self-cure acrylic resin and irradiated using the three LASER systems at lower energy densities. Post irradiation, the microhardness of enamel in the pit and fissure region was measured using Vickers microhardness test. Scanning electron microscopy analysis was done to check the microstructural changes of the lased enamel. Data obtained were subjected to Kolmogorov-Smirnov test and ANOVA with statistical significance set at P ≤ 0.05. Results: All three groups showed an increase in microhardness when compared to the value taken as control (control - 209.6, diode - 237.56 ± 19.27, CO 2 -294.92 ± 29.38, erbium - 264.39 ± 11.83). ANOVA test revealed a highly significant (P = 0.001) difference between the means of the three groups. Tukey post-hoc analysis showed that CO 2 LASER showed a higher increase in microhardness followed by erbium and diode LASER. Conclusion: This study revealed that the increase in microhardness and microstructural changes obtained with CO 2 LASER was higher than the other two LASER systems. Furthermore, diode LASER can be used as a viable option for fissurotomy procedure as it improves the hardness of enamel, with a homogenous sealing effect of the pits and fissure.