The importance of the effect of rapid and slow maxillary expansion treatments on changes in palatal rugae morphology in forensic identification

In this study, it was aimed to determine in three dimensionally the changes in the palatal rugae morphology of patients who underwent rapid and slow maxillary expansion treatment and to determine the correct use of the palatal rugae region in forensic identification. Between the ages of eight and 28 male and female individuals were included in the study who have not received orthodontic treatment before, had a posterior crossbite, do not have habits such as tongue thrusting or thumb sucking, do not have any pathology in the palatal rugae area and whose pre- and post-treatment plaster models are of good quality, who receive treatment with and/or without extraction. Three groups were formed from the patients who met the inclusion conditions in the study: those who received rapid maxillary expansion treatment (group 1), slow maxillary expansion treatment (2nd group), and fixed orthodontic treatment (3rd group). Fast and slow orthodontic expansion treatment represents the experimental group, and fixed orthodontic treatment represents the control group. 24 patients who had RPE treatment, 22 patients who had SME treatment, and 18 patients who had fixed orthodontic treatment were included in the study. Plaster models of patients who underwent rapid and slow maxillary expansion treatment and fixed orthodontic treatment were scanned with an extraoral model scanner (Sirona inEos X5, Dentsply Sirona, Bensheim, Germany) and a digital model was created and STL saved in format. The produced STL files were transferred to Mimics (Materialize Mimics Innovation Suite 23, 3-matic Version Medical 17, Materialize) software. Rugae were classified according to Lysell's palatal rugae classification method; It was named as the first ruga at the front, the second ruga, and the third rugae at the back. Upper jaw palatal rugae anteroposterior points, transverse points, angular angle measurement points, palatal area, and volume points were marked. The plaster models taken at the beginning of the treatment (pre-expansion) were recorded as T1, and the plaster models taken at the end of the treatment (post-expansion) were recorded as T2. In patients who undergo expansion treatments, the anterior and mesial rugae are not stable in the anteroposterior direction. In patients who receive fixed orthodontic treatment the 2nd-3rd. rugae region and distal endpoints in general are not safe in terms of stability. In the RPE and SME groups, the largest change in transverse-1 and transverse-2 measurements was measured in the 1st Ruga. The stability of the mesial endpoints in the anteroposterior-1, anteroposterior-2, and transverse-1 directions of the control group receiving fixed orthodontic treatment is safer. In the control group, the greatest change in transverse-1 and transverse-2 measurements was measured in the 3rd ruga. According to the results we obtained in the study at the control group the 1st Ruga was found to be more stable in the anteroposterior and transverse planes. It was concluded that the findings we obtained as a result of this thesis study will be guiding for the changes that can be seen in the palatal rugae region with palatal treatments performed in our society. Accordingly, it is thought that maxillary expansion treatments and fixed orthodontic treatment will cause changes in the palatal rugae area and will not be reliable in identification.