Synergistic Effect of Nd:Yag Laser Combined with Fluoride Varnish on Inhibition of Caries Formation in Dental Pits and Fissures in Vitro

BACKGROUND AND PURPOSE: Although the effectiveness of neodymium yttrium aluminum garnet (Nd:YAG) laser and fluoride anticaries treatment has been established, most previous studies focused on smooth tooth surfaces. We evaluated the anticaries effects of Nd:YAG laser combined with fluoride varnish (Duraphat) on caries-susceptible pit and fissure areas. METHODS: A total of 36 noncarious molars were treated with either a Nd:YAG laser (2. 5 W, 6 sec) followed by fluoride varnish, Nd:YAG laser only, fluoride varnish only, or no treatment (control). Artificial carious lesions were created to assess the acid resistance of enamel after treatment. Undecalcified successive tooth slices were made. Percentage lesion formation, lesion length, and lesion depth were evaluated using polarized light microscopy . RESULTS: The Nd:YAG laser enhanced the resistance of dental enamel to acid challenge. However, Nd:YAG laser alone was not as effective as the Nd:YAG laser combined with fluoride varnish, especially for the treatment of pits and fissures. Nd:YAG laser treatment combined with fluoride varnish inhibited 43% of lesions at pits and fissures and 80 % of lesions on smooth surfaces compared to no treatment. Carious lesions had shallower depth and shorter length. No carious lesion extended beyond the dentinoenamel junction in either laser-treatment group. CONCLUSIONS: A synergistic effect on dental caries prevention in pit and fissure areas and on the smooth surfaces of the tooth can be achieved by applying Nd:YAG laser followed by fluoride varnish