Quantitative Assessment of Posterior Maxillary Arch for Orthodontic Mini-screw Insertion Using Cone Beam Computed Tomography- a Cross Sectional Analysis

Abstract Background and aimThe aim of this study is to assess the cortical bone thickness and inter-radicular distance between posterior maxillary teeth using Cone Beam Computed Tomography (CBCT).Methods and materialCone beam computed tomography records of 35 patients (70 quadrants) from maxilla were evaluated. The images were analyzed using NNT viewer Software (Version 23). The measurements were made on axial sections at 2, 4, 6 and 8 mm from the CEJ. The optimal sites were defined in terms of (a) mesiodistal palatal or buccal inter-radicular distance, (b) alveolar cortical bone thickness and (c) palatal or buccal safe depth of bone for mini-screw insertion. Descriptive statistics, paired T-test and repeated measure ANOVA were used to analyze the data.ResultsThe mean buccal inter-radicular distance was lowest between first and second molar (2.44 mm) and highest between first and second premolar (3.28 mm). The mean palatal inter-radicular distance was lowest between first and second premolar (3.64 mm) and highest between second premolar and first molar (5.30 mm).The mean buccal safe depth was lowest between canine and first premolar (1.96 mm) and highest between first and second molar (2.61 mm). The mean palatal safe depth was lowest between second premolar and first molar (3.35 mm) and highest between first and second molar (3.56 mm). The thinnest and thickest buccal cortical thickness was detected on canine and first molar (1.04 mm) and on the second premolar and second molar (1.56 mm). ConclusionThe quantity and quality of the maxillary alveolar process is an important factor to decide where to insert the orthodontic mini screws, necessitating careful preoperative evaluation.