Effects of low-intensity red laser radiation on the dentine-pulp interface after class I cavity preparation disfunction

The aim of this study was to investigate the effects of low-intensity red laser radiation on the ultrastructure of dentine-pulp interface after conventionally prepared class I cavity preparation. Eight premolars indicated for extraction for orthodontic reasons from 2 patients were used. Class I cavities were prepared and the teeth were divided into two groups. The first group received a treatment with a GaAlAs laser, l= 660 nm, P= 30 mW and D= 2J/cm2. The laser tip was applied directly and perpendicularly into the cavity in only one sense. The teeth from the second group had their class I cavities prepared but they did not receive the laser therapy. All cavities were filled with composite resin. Twenty-eight days after the preparation, the teeth were extracted and processed for transmission electron microscopy analysis. Two sound teeth (healthy group) without any preparation were also examined. The first group presented odontoblastic processes in intimate contact with the extracellular matrix, while the collagen fibers appeared more aggregated and organized than those of the second group. These results were also observed in the healthy teeth. The results suggest that laser irradiation accelerates the recovery of the structures at the dentine-pulp interface involved during cavity preparation layer.