Automatic analysis algorithm for acquiring standard dental and mandibular shape data using cone-beam computed tomography

Abstract

This study aims to introduce a new algorithm developed using retrospective cone-beam computed tomography (CBCT) data to obtain a standard dental and mandibular arch shape automatically for an optimal panoramic focal trough. A custom-made program was developed to analyze each arch shape of randomly collected 30 CBCT images. First, volumetric data of the mandible were binarized and projected in the axial direction to obtain 2-dimensional arch images. Second, 30 patients’ mandibular arches were superimposed on the center of the bilateral distal contact points of the mandibular canines to generate an average arch shape. Third, the center and boundary of a panoramic focal trough were obtained using smoothing splines. As a result, the minimum thickness and transition of the focal trough could be obtained. If this new algorithm is applied to big data of retrospective CBCT images, standard focal troughs could be established by race, sex, and age group, which would improve the image quality of dental panoramic radiography.

Similarity index for intuitive assessment of three-dimensional facial asymmetry

“…Separated images of mandible and soft tissue were binarized and morphological operation was performed for surface area and volume calculation. The holes of each binarized image were filled for accurate measurements, based on the method used in a previous study 28 . Morphological closing (a dilation followed by an erosion) was performed for hole filling of the condylar heads, because the upper portion of the condyle has a very thin cortical layer and is likely to be open-ended after binarization.…”

A New Approach to Set the Absolute Midsagittal Plane of the Mandible Using a Similarity Index in Skeletal Class III Patients with Facial Asymmetry

“…Separate images of the mandible were binarized and a morphological operation was performed for surface area and volume calculation. In each binarized image, the holes were filled using morphological closing (dilation followed by erosion) for accurate measurements, based on the method used in previous studies [17,20]. In this article, a sphere structuring element with a radius of 10 pixels was used for morphological closure.…”