Digital Analysis Of Interproximal Contact Tightness Under Functional Loading

To evaluate the reliability of a new method for quantitative measurement of interproximal contact tightness (ICT) under functional loading and to analyze the ICT change under different bite forces. Twenty volunteers were recruited to participate in bite force control training and intraoral 3D scanning (2022SLL022). Forty sets of scanning data (the posterior teeth data, buccal light, and heavy bite data) were collected and imported into Geomagic to establish the local coordinate system (X: MD, Y: BL, Z: OG), segment the first and second molars (target teeth), create interproximal contact area feature lines, perform virtual bite registration, convert lines into feature points, and analyze their movement (including Dm, DX, DY, and DZ) under functional loading. For reliability evaluation, intraclass correlation coefficients (ICC) of ICT change were compared among the three operators. To assess differences between groups, paired t-tests were employed. Whether the bite was light or heavy, the ICC was in the sequence DY>Dm>DZ>DX, and the change of the maxillary DZ was significantly greater than the mandibular (PZ=0.001, PZ=0.044). The ICT changes were substantially larger under heavy bite compared to light bite for target teeth both maxillary (Pm<0.001) and mandibular (Pm=0.006). The digital quantitative analysis method of the ICT change under functional loading showed good clinical reliability. Notably, under varying bite forces, there were significant differences in the ICT change. The digital method can be used to enhance fixed restoration quality and prevent food impaction.