Use of Er:YAG Laser for Disinfection of Infected Carious Dentin: Microbiological Evaluation and Scanning Electron Microscopy Analysis

OBJECTIVE: To evaluate the antimicrobial efficacy of Er:YAG laser for disinfection of softened carious dentin using subablative parameters. BACKGROUND: Current literature lacks robust scientific evidence supporting the use of Er:YAG laser for disinfection of the entire carious dentin without mechanical removal. METHODS: = 15): Group C (positive control)-carious lesions with no disinfection procedure; Group antimicrobial photodynamic therapy (aPDT, negative control)-application of 0.005% methylene blue followed by low-level laser irradiation delivering 9 J of energy; Group Er:YAG, parameter A-irradiation with Er:YAG laser at 50 mJ of energy; Group Er:YAG, parameter B-irradiation at 40 mJ; and Group Er:YAG, parameter C-irradiation at 20 mJ. A repetition rate of 15 Hz was used for all Er:YAG-irradiated groups. Microbiological outcomes (CFU/mL) were analyzed using the nonparametric Kruskal-Wallis test followed by Dunn's post hoc test, with a significance level set at 5%. RESULTS: 0.05). CONCLUSIONS: Er:YAG laser irradiation at 50 mJ demonstrated antimicrobial efficacy comparable with aPDT for disinfection of softened carious dentin, with a shorter operative time, supporting its potential use as an alternative treatment in minimally invasive dentistry.