Automatic Synthesis of Panoramic Radiographs from Dental Cone Beam Computed Tomography Data

Abstract

In this paper, we propose an automatic method of synthesizing panoramic radiographs from dental cone beam computed tomography (CBCT) data for directly observing the whole dentition without the superimposition of other structures. This method consists of three major steps. First, the dental arch curve is generated from the maximum intensity projection (MIP) of 3D CBCT data. Then, based on this curve, the long axial curves of the upper and lower teeth are extracted to create a 3D panoramic curved surface describing the whole dentition. Finally, the panoramic radiograph is synthesized by developing this 3D surface. Both open-bite shaped and closed-bite shaped dental CBCT datasets were applied in this study, and the resulting images were analyzed to evaluate the effectiveness of this method. With the proposed method, a single-slice panoramic radiograph can clearly and completely show the whole dentition without the blur and superimposition of other dental structures. Moreover, thickened panoramic radiographs can also be synthesized with increased slice thickness to show more features, such as the mandibular nerve canal. One feature of the proposed method is that it is automatically performed without human intervention. Another feature of the proposed method is that it requires thinner panoramic radiographs to show the whole dentition than those produced by other existing methods, which contributes to the clarity of the anatomical structures, including the enamel, dentine and pulp. In addition, this method can rapidly process common dental CBCT data. The speed and image quality of this method make it an attractive option for observing the whole dentition in a clinical setting.

Dental panoramic imaging by use of CBCT projection data

“…In order to extract the dental arch for obtaining a panoramic image, we use the axial maximum intensity projection (MIP) of the CBCT image that can represent the overall structure of the teeth [16, [21][22][23][24][25][26]. The general process for MIP-based methods is to create a MIP image of an axial slice of a speci ed range.…”

“…However, the method of synthesizing the panoramic image from the CBCT image is greatly affected by the quality of the CBCT image and the accuracy of the dental arch [16][17][18][19][21][22][23][24][25][26]. Several algorithms have been reported to automatically extract sophisticated dental arches, but the accuracy of the dental arch is degraded when there are missing teeth and/or metal artifacts in the CBCT image [16,22]. In particular, when metal artifacts are severe, even if the ideal dental arch is set, metal artifacts of CBCT remain in the panoramic image, reducing the quality of the panoramic image.…”

OralViewer: 3D Demonstration of Dental Surgeries for Patient Education with Oral Cavity Reconstruction from a 2D Panoramic X-ray

“…The synthesis is valid since the CT scans contain full 3D information of oral cavity, while panoramic radiographs are the 2D projections of them. Several previous work has demonstrated promising results for high quality X-ray synthesis from CT, and we employed the method from Yun et al [30] in this work. In total, our in-house dataset contains 23 pairs of 3D CT scans and synthesized panoramic X-rays.…”

Reconstruction of Panoramic Dental Images Through Bézier Function Optimization

“…Their work employed optimization techniques to find the best B-spline that approximates the dental arch. Luo et al (2016) proposed a method to automatically synthesize panoramic dental radiographs from various types of dental cone beam CT data. The dental arch curve was initially generated from the MIP projection.…”

“…Luo et al ( 2016 ) proposed a method to automatically synthesize panoramic dental radiographs from various types of dental cone beam CT data. The dental arch curve was initially generated from the MIP projection.…”