[Changes at sutures and pariodontium of fixed teeth due to application of rapid contraction force in maxillary canines in dogs].

This study examines the histologic changes and the orthopedic effect, that might be expected after the application of an interrupted rapid contraction force with a skeleton type device, on the mid-palatal suture in the intercanine area, the sutures between the canines and the fixed teeth paradontium just after rapid contraction and after retention had been reached. Twenty young hybrid adult dogs, which were divided into five groups: a control group, a group of subjects just after rapid contraction, and retention groups at two, four and eight weeks. For the experimental groups, an expansion screw (No. 602-813), made by Dentaurum Co., was fixed between the maxillary canines and left there for two weeks to achieve a contraction with a total reduction of 3.52 mm. Measuring models, decalcified preparations (H.E. stain, Azan stain) and non-decalcified preparations (with hard tissue labeling medication) were used for the method of the study. The application of interrupted rapid contraction force at the maxilla produced a little body fusion on the mid-palatal suture only. However, the extent was very small, and disappeared during the retention. The fixed teeth showed tipping movements, but although there was a reduction of the maxillary width, it was still considered an indication and left a recognizable permanent complication. Thus the procedure is considered to be clinically valuable.