Synergistic effect of Nd : YAG laser combined with fluoride varnish on inhibition of caries formation in dental pits and fissures in vitro

Background acid purpose: Although the effectiveness of neodymium yttrium al uminum garnet (Nd:YAG) laser and fluoride anticaries treatment has been est ablished, most precious studies focused on smooth tooth surfaces. We evalua ted 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, fluor ide varnish only, or no treatment (control). Artificial carious lesions wer e created to assess the acid resistance of enamel after treatment. Undecalc ified successive tooth slices were made. Percentage lesion formation. lesio n 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 nor as effective as the Nd:YAG l aser combined with fluoride varnish, especially for the treatment of pits a nd assures. 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 l ength. No carious lesion extended beyond the dentinoenamel junction in eith er laser-treatment group. Conclusions: A synergistic effect on dental caries prevention in pit and fi ssure areas and on the smooth surfaces of the tooth can be achieved by appl ying Nd:YAG laser followed by fluoride varnish.