Histological evaluation of the effects of corticotomy on induced orthodontic movement in rats

Abstract: Introduction: Alveolar corticotomy is a surgical procedure used to increase the velocity of tooth movement. Objective Identify histological evidence of the effect of corticotomy on orthodontic movement in rats. Material and method Forty-five Wistar rats (Rattusnorvegicus Albinus) were equally divided into three groups: Control Group (CG) - no tooth movement or corticotomy; Movement Group (MG) - tooth orthodontic movement only; and Corticotomy and Movement Group (CMG) - tooth orthodontic movement surgically assisted by corticotomy. In the CMG, surgical procedures consisted in an incision in the palatal, reaching from the mesial to the distal regions of the maxillary right first molar. Tooth movement in the MG and CMG was applied with coil spring force of 40 gF from the maxillary right first molar to the maxillary right incisor. The rats were sacrificed at days 1, 3, and 7, and histological sections were performed to evaluate the counting of osteoblasts and osteoclasts throughout the areas of tension and pressure. Result Histological analysis showed that the CMG presented better cell response to bone neoformation compared with that of the other groups. Greater proliferation of osteoclasts was observed in areas of pressure on day 3, resulting in increased reabsorption, whereas greater proliferation of osteoblasts was observed in areas of tension on day 1, indicating increased bone formation. Conclusion Differences between the treated groups occurred only in the initial period of tooth movement. Therefore, the changes caused by corticotomy are not significant in orthodontic movement to justify this invasive procedure.