An evaluation of the accuracy of CAD-CAM-assisted miniscrew surgical guides from CBCT and digital models

Abstract

The purpose of this study was to evaluate the accuracy of miniscrew placement using CAD-CAM-assisted miniscrew surgical guides (SG) made by fusing CBCT and digital models. Miniscrews were placed in cadaver maxilla using stereolithogragphic CAD-CAM-assisted surgical guides (SG group; n = 25) or periapical X-rays (control group; n = 20). Insertion sites were selected using a 3-dimensional surgical planning program by fusing maxillary digital model images and CBCT images. Deviations between actual and planned placements were measured as 3-dimensional angular deviations and distance (coronal, apical) deviations. The results of the present study were as follows.1.The mean value of the minimum interradicular distance in the maxilla, as seen in the CBCT axial view, was 2.80 ± 0.67 mm (mean ± SD).2.A statistically significant difference was detected in the long-axis angular deviation between the SG group, 3.14°, and the control group, 9.57° (P<0.001).3.The 3-dimensional linear distance deviations of miniscrews in the SG group were 0.73 mm at the coronal position and 0.73 mm at the apex. For the control group, these values were 1.56 mm, and 1.28 mm, respectively. Statistically significant differences were observed between the SG and control groups for both values (P<0.01).4.Deviations differed significantly between operators in the control group (P<0.05), but not in the SG group.5.The SG group had significantly more screws that were classified as middle position than the control group (P<0.05).Surgical guide accuracy was improved by construction using digital model imaging. Miniscrews were placed more accurately when surgical guides were used than when a direct method was used. The stability of miniscrews was greater when inserted using CAD-CAM-assisted surgical guides than when inserted using X-ray radiographs. The accuracy of miniscrews was independent operator’s skills when using surgical guides. This results were reflected expectation of using surgical guides clinically.