Evaluation of the changes caused by orthodontic force onhealthy and periodontally compromised tissues

In our study, we aimed to investigate and compare the changes caused by optimum orthodontic forces in the initial phase on healthy and diseased periodontium through histomorphometric and immunohistochemical methods. For this reason, a split mouth study design was planned with 36 Wistar rats. Rats were divided into 3 groups with 12 animals in each group. The left side of the upper jaws of all animals were determined as the experimental side, and the opposite side as the control. To induce experimental periodontitis, silk ligatures were placed around the second molars in the experimental sides and maintained for 14 days. After removal of the ligatures, orthodontic appliances applying 10 cN force were placed to the maxillary molars on both sides. Rats in the 1st group were sacrificed after the 1st day of appliance, the 2nd group of animals on the 7th day and the 3rd group on the 14th day. Distance between the incisor and the 1st molar was measured at day 0 and sacrification day on both sides in order to determine the quantity of orthodontic tooth movement. After sacrification, the mesiobuccal roots of the maxillary second molars were examined immunohistochemically and histomorphometrically. No statistically significant difference was found as a result of the comparison between experimental and control sides regarding the amount of orthodontic movement, periodontal ligament width, RANK and RANKL antibody findings. There is a statistically significant difference in the mesial region for the OPG antibody when the experimental and control sides are compared, and this difference is in favor of the control side. As a result of the examination and comparison of the changes caused by the optimum orthodontic force application in healthy and diseased periodontium in rats, no significant difference was observed between the experimental and control sides, except for the findings of the OPG antibody on day 14 in the pressure region. In association with clinical practice, it was concluded that the application of optimum orthodontic force did not cause additional destruction on periodontal tissues during the initial phase of orthodontic movement in the presence of a history of periodontitis.