[Changes with time in incomplete root and periodontal tissues of young dog teeth with torque loading applied]

We investigated, using labeling techniques (tetracycline, calcein) and routine histopathological methods (H. E. and Azan stainings), the histological changes with passage of time in incomplete root and the periodontium of young dog teeth with torque loading applied. The maxillary left first, second and third incisor teeth were used as anchorage teeth, and the maxillary right second incisor was loaded with either 3 degrees or 9 degrees torque. The orthodontic forces of these are 20-30 g and 80-90 g, respectively. Some temporal disturbances (such as mild, moderate, or severe bendings of labial and palatal apexes) were observed in certain regions of the apex of the incomplete root. However, with subsequent development of the root, the disturbances were repaired and pulp of the teeth was normally formed. Furthermore, although periodontium was also temporarily disturbed, it developed normally with the passage of time.