Comparative Analysis of Occlusal Parameters in Post-Orthodontic Patients with and without Non-Carious Cervical Lesions Using T-Scan III

This study aimed to determine the relationship between occlusal and clinical factors—including relative occlusal force, occlusion time (OT), disclusion time (DT), and occlusal schemes—and the occurrence of non-carious cervical lesions (NCCLs) in post-orthodontic patients, using the T-Scan III system. Fifty-two patients who completed fixed orthodontic treatment within 1 year were purposively selected and divided into two groups: those with NCCLs (n = 26) and those without NCCLs (n = 26). A total of 1,336 teeth were evaluated (111 with NCCLs, 1,225 without). Data collection included a questionnaire, clinical examination, and T-Scan III recordings. Pearson's chi-square and multiple comparison tests were used for categorical variables. Relative occlusal forces were compared using the Mann–Whitney U-test, while OT and DT were analyzed with independent-sample t-tests. Multiple linear regression identified predictive factors for NCCLs at both the subject and tooth levels. The significance level was set at p < 0.05. Older age, combined orthodontic–orthognathic surgery, and gingival recession were significantly associated with NCCL occurrence (p < 0.05). Group-function occlusion was the only significant occlusal predictor (β = 0.365, p = 0.018). At the tooth level, gingival recession significantly predicted NCCLs (β = 0.499, p < 0.001). The regression models explained 12.5 and 22.9% of the variance in NCCL occurrence at the subject and tooth levels, respectively. Teeth with NCCLs showed higher relative occlusal forces at maximum intercuspation (8.16 ± 8.41%) and during eccentric movements (37.86 ± 31.38%) than teeth without NCCLs (7.53 ± 9.26% and 30.09 ± 29.16%, respectively; p < 0.05). Mean OT (0.27 ± 0.07 seconds) and DT (0.50 ± 0.13 seconds) were significantly longer in NCCL subjects than in controls (OT: 0.22 ± 0.06 seconds; DT: 0.42 ± 0.11 second; p < 0.05). Prolonged occlusion and DTs, higher relative occlusal forces, and group-function occlusion were significantly associated with the presence of NCCLs in post-orthodontic patients. Quantitative occlusal analysis using the T-Scan III system may help clinicians detect functional imbalances and prevent NCCL development during orthodontic follow-up.