RESUMEN
OBJECTIVE: The aim of the present study was to compare the in vitro effects of the Er:YAG laser, an ultrasonic system, and manual curette on dentine root surface by roughness and micro-morphological analysis. MATERIALS AND METHODS: Thirty-six flattened bovine roots were randomly assigned to one of the following groups: group 1 (n = 12): Er:YAG laser (2940 nm), 120 mJ/pulse, 10 Hz, 8.4 J/cm2; group 2 (n = 12): ultrasonic system; and group 3 (n = 12): manual curette. The mean surface roughness (Ra) of each sample was measured using a profilometer before and after the treatments. The micro-morphology of the treated and untreated (control) root surfaces was evaluated with scanning electron microscopy (SEM) at 50x and 1000x magnification. RESULTS: Analysis with the profilometer showed that for equal times of instrumentation, the smoothest surfaces were produced by the Er:YAG laser and the ultrasonic system, followed by the curette (p < 0.05). Morphological analyses demonstrated that treatment with the Er:YAG laser produced some areas with an irregular surface, craters, and ablation of the intertubular dentin. The smear layer was removed and dentine tubules were opened by both curettes and the ultrasonic system. The micro-morphology of the dentine root surface after ultrasonic treatment, however, demonstrated randomly distributed areas cratering. CONCLUSION: All instruments increased the roughness of the dentine root surface after treatment; however, the curette produced rougher surfaces than the other devices. SEM analysis revealed distinct root surface profiles produced by the three devices.