Evaluation of cortical bone thickness of mandible with cone beam computed tomography for orthodontic mini implant installation

Abstract

Achieving maximum anchorage without movement of the teeth in anchorage unit has been a great challenge in orthodontics and the success of the treatment plan is highly dependent on it. But determination of a proper site for installation of mini implants is still one of the most common problems in this field. Nowadays the use of CBCT which provides 3-D images with acceptable quality is being widely spreaded in all fields of dentistry such as orthodontics. Materials and Methods: In this study 40 CBCT images of mandibulars arch from distal of canine to mesial of second molar were studied. The images were sectioned axially in 2mm diameter and the reference point was CEJ. To determine cortical bone thickness tangent lines were drawn buccolingually to the roots in axial section and a third line were drawn from the middle of these two lines, and the cortical bone thickness was measured where the third line crosses the buccal cortex. Results: The results of this survey demonstrates that cortical bone thickness increase from CEJ to apex in all sites; and this increase is statistically significant (P<0.001) while this increase was not statically significant at the 3-4(site). Comparing the 4 mm section in all sites showed significant increase from anterior to posterior.