Er:YAG laser in selective caries removal and dentin treatment with chitosan: a randomized clinical trial in primary molars.

ABSTRACT

This study evaluated the effect of chitosan on dentin treatment after selective removal of caries lesions with ErYAG laser in reducing Streptococcus mutans, as well as its effect on the performed restorations. The sample consisted of children (aged 7 to 9 years) with active carious lesions and dentin cavitation located on the occlusal surface of deciduous molars. Eighty teeth were randomly distributed into 4 groups according to the caries removal method: ErYAG laser (250 mJ/4 Hz) or bur and dentin surface treatment 2.5% chitosan solution or distilled water. The bacterial load of caries-affected dentin was quantified by counting CFU/mg (n = 10). The teeth were restored and evaluated at 7 days, 6 months, and 12 months using modified USPHS criteria (n = 20). Microbiological data was analyzed by Mann-Whitney and clinical analyses were done using Kruskal-Wallis and Dunn test (α = 0.05). The results showed that the ErYAG laser significantly reduced the amount of Streptococcus mutans (p = 0.0068). After dentin treatment with chitosan, there was a significant reduction in the amount of Streptococcus mutans for both removal methods (p = 0.0424). For the retention and secondary caries criteria, no significant differences were observed along the evaluated time (p > 0.05). The laser-treated group was rated "bravo" for discoloration (p = 0.0089) and marginal adaptation (p = 0.0003) after 6 and 12 months compared to baseline. The ErYAG laser reduced the amount of Streptococcus mutans and the chitosan showed an additional antibacterial effect. After 1 year, the ErYAG laser-prepared teeth, regardless of the dentin treatment, showed greater discoloration and marginal adaptation of the restorations.