Comparison of the accuracy of a cone beam computed tomography-based virtual mounting technique with that of the conventional mounting technique using a facebow

Abstract

Statement of problem: The introduction of digital technology in dentistry has resulted in a shift from conventional methods to digital techniques. However, mounting a digitized dental cast on a virtual articulator is challenging. Several techniques have been suggested to resolve this problem, but in the absence of a standardized method, digitized dental casts are often mounted arbitrarily on a virtual articulator.

Purpose: The purpose of this clinical study was to compare the accuracy of a novel virtual facebow transfer (VM) technique based on cone beam computed tomography (CBCT) with that of the conventional mounting (CM) technique using a facebow.

Material and methods: Five repeated mountings were performed with each technique for 15 participants. In the CM group, dental casts were mounted using a facebow record and scanned for transmission to the virtual dental space. In the VM group, digital dental casts were mounted on the standard tessellation language file of a reference articulator by reconstructing a file of the participant's skull from CBCT data. In this group, a virtual facebow, prepared by scanning the articulator and facebow complex, was used. After the CM and VM casts had been aligned, the coordinates of target points set on the maxillary right central incisor, maxillary right first molar, and maxillary left first molar were determined, and the mean ±standard deviation distance between the target points was calculated to compare the precision of the techniques. Additionally, vectors of the target point on the maxillary right central incisor were compared to analyze the spatial difference between the techniques. Finally, the occlusal plane angle was calculated. For the correlation analysis of repeated measured data, a 1-way repeated measures analysis of variance (ANOVA) was first performed. The Kolmogorov-Smirnov test was performed to determine normality, and a paired t test and the Wilcoxon signed rank test were performed for normally and nonnormally distributed variables, respectively (α=.05).

Results: The mean distance between target points was significantly greater in the CM group (4.72 ±1.45 to 5.17 ±1.54 mm) than in the VM group (2.14 ±0.58 to 2.35 ±0.60 mm) (P<.05). The standard deviation between target points was significantly greater in the CM group (1.60 ±0.64 to 2.30 ±0.87 mm) than in the VM group (0.74 ±0.23 to 1.12 ±0.45 mm) (P<.05). The maxillary right central incisor was located more anteriorly in the VM group than in the CM (100%, P<.05) group. The occlusal plane angle was significantly steeper in the CM group than in the VM group (8.14 degrees versus 2.13 degrees, P<.05).

Conclusions: The VM technique was more precise than the CM technique. VM casts were positioned ahead of CM casts. Further, the occlusal plane angle tended to be steeper with the CM technique than with the VM technique.