# DeAPIR: Efficient and Enhanced Dental Arch-Guided Panoramic Image Reconstruction from CBCT Data
###### Abstract  
Dental CBCT and panoramic imaging play a pivotal role in dental diagnosis and treatment planning, alongside the indispensable use of computed tomography (CT) and X-ray imaging in dentistry, particularly for surgical planning. Given the widespread adoption of dental cone beam CT in clinics today, we explore a novel approach in this study--utilizing CT's three-dimensional (3D) data to reconstruct a two-dimensional (2D) panoramic dental image. This method eliminates the requirement for an extra panoramic scan. In this work, we propose a novel framework to generate an enhanced and extended 2D panoramic view by using the dental arch extracted from 3D CBCT. Our method involves segmenting the patient's dental arch from their 3D CBCT image by identifying horizontal slices with above-average intensity, followed by morphological operations, including dilation, Gaussian filtering, and skeletonization, to delineate the dental arch line. Additionally, we extend the dental arch beyond the wisdom teeth using quadratic curve fitting. Finally, we employ Maximum Intensity Projection on rotated cubic segments aligned with the dental arch curve to produce captivating panoramic images. The panoramic view produced using our proposed method, when compared to the results obtained from BlueSky and OpenInventor, exhibited superior enhancements and greater accuracy in panoramic visualization. C 2023 13 12365 11 October 2023 5 November 2023 14 November 2023 15 November 2023  
C 2023 by the authors. Liconse MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ([[https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/)]([https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/))). C 2023 13 12365 113 1  
persists, driven by the presence of intricate anatomical structures within a single field of view. These structures are of paramount importance for surgical planning. Two methods are available for capturing comprehensive panoramic images: a hardware-based approach and a software-driven approach. The hardware approach involves the CBCT scanner's rotating shaft following a predefined trajectory [9]. However, fixed scan trajectories can result in out-of-focus panoramic images when the patient's dentition significantly deviates from the focal plane, and additional radiation exposure occurs during an extra panoramic scan [10]. In contrast, software approaches create panoramic images from dental CBCT data by extracting image slices at uniform dental arch angles [11]. This process typically involves two steps: first, extracting the dental arch that represents the teeth and jawbone, and second, extracting the maximum intensity projection from the volumetric CT data near the dental arch coordinates and incorporating it into a panoramic image view. This approach allows panoramic image acquisition without requiring hardware modifications to existing dental CBCT equipment [12]. Unlike panoramic scan systems, software-based methods do not suffer from out-of-focus issues because they extract the panoramic image along the dental arch. However, the quality of these methods depends on the CBCT image's quality and the accuracy of the dental arch. Various algorithms have been developed to automatically extract precise dental arches, but their accuracy diminishes in the presence of missing teeth and metal artifacts in the CBCT image [13]. Severe metal artifacts can persist in the panoramic image despite setting an ideal dental arch, ultimately reducing the panoramic image's quality [14]. In their work [14], the authors employed a binary thresholding technique followed by morphological operations on the teeth slice section to accurately extract the dental arch curve from the CBCT data.