Reliability and Validity of T-scan and 3D Intraoral Scanning for Measuring the Occlusal Contact Area.

TLDR: T-scan is a reliable method for measuring the OCA, but the 3D surface scan is not, and occlusal registration showed a high validity.

Abstract: PURPOSE To determine the reliability of T-scan and 3D intraoral scan techniques for assessing the occlusal contact area (OCA), compared to occlusal registration and also to assess the validity of the techniques. MATERIALS AND METHODS Thirty-one dentate adults participated in this cross-sectional study. T-scan records were used to measure the OCA at maximum bite force and at 50% of maximum force using the software's bite force selection tool. A second method measured the OCA between 2 virtual models scanned intraorally using a 3D surface scan and considering the occlusal contact at 2 interocclusal distances (0-100 and 0-200 µm). The third method measured OCA using occlusal registration at moderate and maximum occlusal force, and considering contact at the 2 interocclusal distances (0-100 and 0-200 µm). Images obtained using the 3 methods were analyzed using ImageJ software. Test-retest reliability was assessed by the intraclass correlation coefficient (ICC) and validity by Pearson correlations. RESULTS ICCs ranged from 0.56 to 0.79 (p < 0.001) for the T-scan; 0.37 to 0.61 (p < 0.05) for 3D surface scan; and 0.92 to 0.95 (p < 0.0005) for occlusal registration. The highest OCA values were obtained using the T-scan, and the lowest using the 3D surface scan. Occlusal registration measurements had the highest correlations with those of the other techniques. CONCLUSIONS T-scan is a reliable method for measuring the OCA, but the 3D surface scan is not. Occlusal registration showed a high validity.