J Oral Laser Applications 10 (2010), No. 2-3 (20.12.2010)
Effect of Er:YAG Laser Irradiation on Fluorosed and Nonfluorosed Root Surfaces: An In Vitro Study
Dhingra, Kunaal / Vandana, K.L. / Shah, Anil / Cobb, Charles M.
Purpose: It is well known that fluorosis may be manifested by abnormal mineralization in teeth. The Er:YAG laser has seen increasing use for treatment of root surfaces exposed to periodontitis. However, there is little information regarding the effects of the Er:YAG laser on root cementum of fluorosed teeth. Therefore, this in-vitro study aimed to evaluate and compare root surface changes following Er:YAG laser irradiation of fluorosed and nonfluorosed teeth.
Materials and Methods: Thirty periodontally healthy fluorosed and nonfluorosed root specimens were irradiated using an Er:YAG laser (2.94 µm wavelength) at 140 mJ/pulse and 10 Hz under a surface-cooling water spray. Examination by SEM was performed to assess laser-induced ultrastructural changes in the root surfaces. Statistical analysis and dichotomous expression of root surface changes in each of the groups were performed for intra- and intergroup comparisons.
Results: Specimens in both treatment groups exhibited evidence of mild thermally induced change, primarily surface melting. Other surface alterations noted in both treatment groups included surface etching, intermittent smear layer, exposure of collagen tufts, and open dentinal tubules. Intergroup comparisons using the dichotomous data indicated that except for melting of root surface, other undesirable morphological changes were found to be more common in nonfluorosed than fluorosed root specimens.
Conclusion: Results of the present study suggest that undesirable morphological changes were similar for both the HF and HNF groups. The results also indicate that further in vitro studies are required, using a variety of lower energy settings, before clinical trials can be initiated that would evaluate the use of the Er:YAG laser for treatment of teeth with fluorosed root structure. Also, observation of etched root surfaces with smear layer after laser irradiation may necessitate additional chemical acid etching for composite restoration for treatment of root caries if indicated.
Keywords: Er:YAG laser, fluorosis, cementum, scanning microscopy