Effects of proximal box depth and adjacent tooth distance on intraoral scans of inlay preparations

抄録

Purpose: To evaluate the effect of proximal box depth and adjacent tooth distance on intraoral scans for inlays.

Methods: Inlay preparation models were designed using a three-dimensional (3D) printing software (Materialise Magics) and manufactured using digital light processing. The models were categorized into three groups based on proximal box depths (4, 6, and 8 mm) and three groups according to adjacent tooth distances (1.2, 1.6, and 2.0 mm). Intraoral scans were performed 10 times using CEREC Primescan (Dentsply Sirona) and TRIOS 3 (3Shape). Reference scan data were obtained using a laboratory scanner (D900L; 3Shape). 3D comparisons between the scan data were performed using 3D analysis software (Geomagic Control X). The root mean square value was calculated to evaluate the trueness of the intraoral scans. Two-way analysis of variance and post-hoc testing with the Bonferroni correction were performed in trueness (α=0.05). Color-coded maps were obtained for the qualitative analysis of deviation.

Results: As proximal box depth increased from 4 mm to 8 mm, the deviation in trueness significantly increased. Similarly, the 1.2 mm distance group showed a greater deviation than the 1.6 and 2.0 mm distance groups. No statistically significant difference was observed between the 1.6 and 2.0 mm distance groups.

Conclusions: The accuracy of intraoral scans is affected by proximal box depth and adjacent tooth distance. A shallow proximal box and a greater distance to adjacent tooth enhance scanning accuracy. However, beyond a certain threshold, further increases in the distance from the adjacent tooth does not improve the scanning accuracy.