To evaluate the clinical application value of T-Scan Ⅲ system in the evaluation of occlusal reconstruction and restoration effect of fixed dentures.

A retrospective analysis was conducted on the T-Scan Ⅲ dynamic bite data of 22 patients who were clinically diagnosed and completed fixed denture bite reconstruction in the Department of Prosthodontics, the Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University from January 2022 to December 2023. The detection time points included: Before bite reconstruction (T0), immediately after restoration (T1), and 1 year after restoration (T2). The analysis parameters included: Asymmetry index of the occlusal force (AOF), Central occlusal force (COF) position, Occlusion Time (OT) and Disocclusion Time (DT), percentage of left and right occlusion force distribution, etc. SPSS 18.0 software was used for statistical analysis of the data, and t-test or McNemar-test was used to compare the differences before and after treatment.

The AOF of patients undergoing fixed denture occlusal reconstruction decreased significantly from T0 stage (32 ± 10) % to T2 stage (10 ± 6) % (t = -5.820, P<0.001), and the balance of bite force distribution was significantly improved. The proportion of COF located outside the functional center decreased from 77.3% (17/22) in T0 phase to 13.6% (3/22) in T1/T2 phase (χ²=12.071, P<0.001), and the distance from the midline shortened from (9.80 ± 3.89) mm to (3.60 ± 2.04) mm (t = -5.391, P<0.001). OT shortened from (0.97 ± 0.14) s to (0.33 ± 0.10) s (t = -6.343, P<0.001) ; The DT of protrusive movement decreased from (0.81 ± 0.11) s to (0.19 ± 0.05) s (t = -6.445, P<0.001). The excursive movement DT showed synchronous improvement (t_{left side}=-6.340, P_{left side}<0.001; t_{right side}=-6.395, P_{right side}<0.001) .

T-Scan Ⅲ can be used for quantitative analysis of bite reconstruction effects, providing reliable basis for clinical evaluation and adjustment of treatment plans.