Histologic Evaluation of the Effect of Trauma from Occlusion on Pulpitis and Periapical of Dogs' Molar: An Animal Study

  Inappropriate occlusal contacts may have deleterious effects on dentofacial system. Regarding the importance of the effect of trauma from occlusion on pulpal inflammation and periapical destruction, the present study was performed to evaluate the trauma effects on pulp and periapical histologically. This study was conducted on the basis of an experimental design for animal studies. Composite repairs, 1.5 mm in height, were placed on the right mandibular first molars of 16 dogs (2 randomized groups of 8 cases). One group of dogs were perfused after 48 hours and the second group were subjected to perfusion after 30 days. Subsequently, the histologic examination was performed and the data were analyzed using SPSS (version13). The levels of inflammation in coronal and apical pulp, periapical, and periodontal ligament (PDL) after 48 hours were obtained as 25%, 37.5%, 12.5%, and 12.5% and were 37.5%, 50%, 25% and 12.5% in maxillary and mandibular molars, respectively. After 30 days, the levels of inflammation were 75%, 75%, 12.5%, and 12.5% and were 87.5%, 100%, 25%, and 25% in maxillary and mandibular molars, respectively. The levels of pulp and periapical inflammation after 30 days were significantly more than those after 48 hours (P<0.001). The apical pulp obtained more inflammation compared to the coronal one. In addition, the periapical inflammation was more developed than that of PDL (P<0.001). Following the trauma from occlusion on dog’s molar teeth, the levels of pulp and periapical inflammation after 30 days were significantly higher than those after 48 hours.The lower teeth inflammation was more chronic and pronounced; however, there was no significant association between the severity and type of inflammation following the acute and chronic trauma and tooth positions