Comparative histopathological analysis of human pulps after class I cavity preparation with a high-speed air-turbine handpiece or Er:YAG laser

The purpose of this study was to comparatively evaluate the response of human pulps after cavity preparation with different devices. Deep class I cavities were prepared in sound mandibular premolars using either a high-speed air-turbine handpiece (Group 1) or an Er:YAG laser (Group 2). Following total acid etching and the application of an adhesive system, all cavities were restored with composite resin. Fifteen days after the clinical procedure, the teeth were extracted and processed for analysis under optical microscopy. In Group 1 in which the average for the remaining dentin thickness (RDT) between the cavity floor and the coronal pulp was 909.5 μm, a discrete inflammatory response occurred in only one specimen with an RDT of 214 μm. However, tissue disorganization occurred in most specimens. In Group 2 (average RDT = 935.2 μm), the discrete inflammatory pulp response was observed in only one specimen (average RDT = 413 μm). It may be concluded that the high-speed air-turbine handpiece caused greater structural alterations in the pulp, although without inducing inflammatory processes.