Cone Beam Computed Tomography and Digital Model Analysis of Maxillary Posterior Buccal Alveolar Bone Thickness for Vertical Temporary Anchorage Device Placement

Abstract

BACKGROUND AND OBJECTIVES: This study aimed to quantify the maxillary posterior buccal alveolar bone thickness (BABT) to provide a practical guideline for vertical temporary anchorage device (TAD) placement using cone beam computed tomography (CBCT). It also aimed to develop a linear regression model for use in digital models for the prediction of available BABT. MATERIALS AND METHODS: We studied 45 cases where vertical TADs were successfully inserted in inter-radicular space in the maxillary posterior area (24 patients: mean age, 28.75: range, 18-44 years). At 3 points of inter-radicular space, BABT was measured using both CBCT and the digital model. In CBCT, BABT was calculated at the most convex point of the lamina dura of the root adjacent to the vertical TAD mesially, at the most convex point of the lamina dura of the root adjacent to the vertical TAD distally, and at the central point between the mesial and distal points. Three linear measurements were obtained at 2, 4, and 6 mm apical to the alveolar crest: the mesial thickness (mesialCBCT), the central thickness (centralCBCT), and the distal thickness (distalCBCT). In the digital model, the most convex points of the clinical crowns of 2 teeth adjacent to vertical TAD and their contact point along with their corresponding WALA ridge were determined. The linear measurements paralleling to model base were digitally recorded at 3 positions: the mesial, central, and distal points. Then, the following 3 linear measurements were measured on each digital model: the mesial thickness (mesialModel), the central thickness (centralModel), and the distal thickness (distalModel). RESULTS: In both the CBCT and digital models, BABT at the central position (centralCBCT = 3.54 mm, centralModel = 6.44 mm) was thicker than that at the 2 exterior positions (mesialCBCT = 2.19, distalCBCT = 2.41 mm, and mesialModel = 2.81 mm, distalModel = 3.04 mm). CBCT BABT was thinnest at 2 mm from the alveolar crest, and no statistically significant was found difference between CBCT BABT at 4 and 6 mm. There was a strong correlation between centralModel and centralCBCT. CONCLUSIONS: The mean BABT at the central position, where we suggest placing vertical TADs, was 3.54 0.74 mm in CBCT and 6.44 1.18 mm in the digital model. The minimum BABT at the central position where vertical TAD was placed successfully was 2.27 mm in CBCT and 4.01 mm in the digital model. There was a strong correlation between centralCBCT and centralModel, and we developed a linear regression model that resulted in a useful fomula for estimating the actual available BABT at the central position: centralCBCT = 0.569 × centralModel.