Examination of chewing performance with extraction and non-extraction fixed orthodontic treatment – A prospective clinical 1-year study

It shows that patients receiving orthodontic treatment may have a risk of developing temporomandibular disorder symptoms. The aim of this study is to examine the changes in the chewing system of occlusal contact parameters related to joint vibrations, chewing patterns, and measured excursive movements in fixed and non-extractive orthodontic treatments. A total of 43 individuals with premolar extraction (n = 23) and without extraction (n = 20) who applied to the Department of Orthodontics, Dentistry Faculty of Istanbul Aydin University and needed orthodontic treatment were included in the study. In this study, 43 active fixed orthodontic treatment patients were conducted at the beginning (T0) and 6th month (T1) and 12th month (T2) on the parameter recorded during chewing. For occlusion analysis, T-Scan® computerized occlusion analysis recording and examination of the chewing pattern were used for JVA and JT temporomandibular joint parameters. Depending on whether the data showed normal distribution or not, differences between groups were evaluated using the Mann–Whitney or independent t-test, and intragroup differences were evaluated using the Wilcoxon sign test or paired t-test. At the beginning, 6th month and 12th month of orthodontic treatment, it was observed that the opening, closing, and occlusion times and joint vibration frequencies in the chewing pattern in cases with and without tooth extraction, the integral value differences of total integral, and frequencies below 300 Hz and above 300 Hz were statistically significant (P < 0.001). In digital occlusion analysis values, the right-left differences were not found statistically significant in the measurements made in cases with and without extraction (P > 0.05), while there were statistically significant differences in disclusion values at the beginning, 6th and 12th months (P < 0.05). At the beginning of the orthodontic treatments with or without extraction, it was observed that the values at the joint level changed significantly in the 6th month. However, the changes in the joints during the treatment, when they return to their ideal values at the end of the 12th month, are more than the change in occlusion.