Bone and root resorption: Effects of the force developed during periodontal ligament injections in dogs

Abstract

The purpose of this study was to determine the role of the pressure generated during the intraligamentary injection technique on the occurrence of root and bone resorptions in dogs. Five beagles were used in the study, and interventions were scheduled to provide observation periods at 7, 25, and 45 days. One hundred five sites on the dogs were divided into three groups: (1) those subjected to needle penetration; (2) those subjected to saline solution injection; and (3) the control sites. Injections were made with a specially designed syringe equipped with a miniaturized force transducer. The dogs were then killed, and block sections of the sites were made and treated in accord with standard histologic procedures. The mean number of osteoclasts and odontoclasts was calculated for each group, and the mean value of bone and tooth resorption angle was measured. Data were then analyzed statistically. Results showed that, at 7 days, needle penetration and saline solution injection caused osteoclastic activity and bone resorption; the number of osteoclasts and the extent of bone resorption were greater in the group that received the injection of saline solution. No difference was found for the odontoclastic activity and tooth resorption. A correlation was found between the force developed during injection, the mean number of osteoclasts, and the mean angle of bone and tooth resorption. At 25 and 45 days, healing had occurred. These findings suggest that fluid pressure within the periodontal ligament is sufficient to initiate osteoclastic, reversible bone resorption.