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ABSTRACT Introduction: Medical imaging continues to play an increasing role in health care and is an integral part of medicine and dentistry. Recent technological advancements have led to the development of fully automated landmark identification (ALI) systems capable of tracing Cone-Beam Computed Tomography (CBCT). The purpose of this study was to evaluate the accuracy and reliability of an ALI system as a tool for automatic landmark location compared to human judges. Methods: One hundred subjects’ CBCT volumes from multiple imaging centers were traced by two human judges who were calibrated and had an ICC close to 1. Fifty-three landmarks were identified in the x, y, and z coordinate planes using Checkpoint Software (Stratovan Corporation, Davis, CA). The ground truth was created by calculating the mean values of the x, y, and z coordinates for each landmark across both judges’ landmark identification. To evaluate the accuracy of ALI, the mean absolute error at each coordinate and mean error distance (mm) between the human landmark identification (ground truth) and the ALI were determined, and a successful detection rate (SDR) was calculated. Results: Overall, the ALI system was as successful at landmarking as the human judges with the exception of a few landmarks. The mean error distance for all 53 landmarks was 4.04 mm ± 6.5. Forty-nine out of 53 landmarks were located within a mean error of 4mm when the average for the coordinates of human judges was considered as a ground truth. Conclusion: Across all three coordinate planes, 96% of the landmarks had a mean absolute error of less than 4mm when compared to the ground truth. The ALI was more precise than humans when identifying landmarks on the same image at different times. This study demonstrates the promise of ALI in aiding orthodontists with landmark identification on CBCTs in the future.

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AIM/PURPOSE: To investigate the correlation between the histopathology of periapical lesion of endodontic origin and the radiographic findings of the maxillary sinus observed by cone-beam computed tomography (CBCT). MATERIAL AND METHODS: Retrospective record review study, data collected of patients received surgical root canal treatment at Boston University school of dental medicine. Total of 39 periapical lesions all had CBCT scans and pathology reports. Each periapical lesion was biopsied and examined by oral & maxillofacial pathologist. CBCT scans for each lesion were examined by two examiners: endodontic resident and board-certified endodontic faculty. RESULTS: 65% of the lesions associated with changes in the maxillary sinus and 35% had no changes as seen on the CBCT scans. 82% of the lesions were granulomas 15.5% were cysts and 2.5% OKC. Out of the 65% (26 lesions) maxillary sinus changes were 50% (13) were periapical mucositis (PAM) & 50% (13) were periapical osteoperiostitis (PAO). CONCLUSION: Histopathology of the periapical lesion didn’t have an effect on the type of changes observed in the sinus. And the closer the lesion was to the sinus the more chances of developing changes in the sinus.

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Syfte: Undersöka om skillnad föreligger mellan panorama- och CBCT-röntgen i avseende att bedöma den vertikala höjden av alveolarutskottet vid planering inför implantatbehandling i utvalda regioner. Metod och material: Totalt valdes 68 röntgenbilder, 34 panorama- respektive 34 CBCT-bilder, ut. I samtliga röntgenbilder utfördes mätningar av alveolarutskottets vertikala höjd, vid specifikt utvalda regioner. Observatörerna bestod av fem tandläkarstudenter. Resultat: Både med och utan hänsyn till outliers, visar resultatet en signifikant skillnad mellan de båda röntgenmetoderna. Generellt visas att mätningar i panoramaröntgenbilder återger ett kortare avstånd mellan alveolarutskottets högsta punkt och sinus maxillaris nedre begränsning/foramen mentales övre begränsning jämfört med mätningar i CBCT-röntgenbilderna. Konklusion: Det fanns en signifikant skillnad mellan de båda röntgenmetoderna, denna studie visade att en kortare vertikal benhöjd mättes i panorama- jämfört med i CBCT-röntgenbilder. Resultatet visade att det fanns försumbara interobservatörsskillnader. / Purpose: Investigate whether there is a difference between the panoramic and CBCT X-ray in terms of assessing the vertical height of the alveolar ridge when planning for implant treatment in selected regions. Methodology: A total of 68 X-ray images, 34 panoramic and 34 CBCT images, were selected. In all X-ray images, measurements of the vertical height of the alveolar ridge were performed at specifically selected regions. The observers consisted of five dental students. Results: The result of this study shows a significant difference between the two X-ray methodologies. The measurements made in the panoramic pictures shows a shorter distance between the highest point of the alveolar bone and the lowest point of the maxillary sinus (or the upper limitation of the mental foramen) compared to the same measurements made in the CBCT pictures. Conclusion: There was a significant difference between the two X-ray methods, this study shows that a lower vertical bone height was measured in panoramic compared to CBCT X-rays. The result showed that there were insignificant inter-observer differences.

Introduction: We argue, for studies of growth or treatment changes, superimposed CBCT images ought to be employed routinely. The location of 3D landmarks on curved structures, however, has been complex. In this study, a reliable method of CBCT superimposition was developed with the aid of AMIRA XImage® software. The specific focus was to develop a practical method for cranial base superimpositions at sella turcica in serial CBCT images. Subsequently, evaluations of the anterior curvature of hypophyseal fossa during growth were completed to confirm the stability. Comparisons of surface changes in the superimposed images in different regions were also made. Methods: Samples of pre- and post-orthodontic CBCT data were procured from Case Western Reserve University. Cranial base changes in 10 adolescent patients of Class I and II hypodivergent, normodivergent, and hyperdivergent malocclusions, were observed over an average interval of 2 years and 5 months. Cranial base models were superimposed using a rigid registration technique, and 3D models constructed from manual segmentation in the AMIRA software. Surface distance changes of the entire cranial base were compared to that of the anterior portion of sella turcica. Results: Mean surface distance changes for the entire cranial base and anterior sella were 0.73-1.57 ± 0.71-1.30 mm and 0.37-0.63 ± 0.29-0.43 mm, respectively. The area above a threshold of 0.5 mm was 61.02-74.11% (cranial base) and 40.70-50.94% (anterior sella) as well. Paired t-tests were applied to compare differences between the mean distance and area above the threshold for data of cranial base versus anterior sella. Both illustrated p-values less than 0.0001 and were statistically significant. Intra-rater reliability was evaluated by completing segmentation and registration three consecutive times on each CBCT volume. Mean surface differences were within 0.01 mm with the exception of one patient. In addition, all subjects exhibited less than 1.00% deviation except three patients, which deviated by 1.03%, 1.46%, and 1.64%, respectively. Conclusions: A practical method of superimposition of serial CBCT images was developed. Through production of color maps, the surface distance of the anterior portion of sella turcica was shown to change much less than the clivus and remaining cranial base structures in pre- and post-treatment scans of growing children. Lastly, the method of superimposition developed here may assist future studies of skeletal changes with accuracy. / Oral Biology