Imaging of the Postoperative Jaws and Temporomandibular Joints.

Surgical procedures in the oral cavity and maxillofacial complex are diverse and involve multiple tissues unique to this region. These procedures are used to remove pathology and infection, restore function, optimize occlusal relationships, prosthetically replace teeth and temporomandibular joints, improve esthetics, and increase upper respiratory tract dimensions. Procedures in the oral cavity are often complicated by infection stemming from the naturally occurring oral flora, but can also be complicated iatrogenically. This article explores the more commonly encountered surgical procedures through examination of the indications, anatomy to consider, and the radiographic imaging of success and failure of these procedures.

Clinically applicable artificial intelligence system for dental diagnosis with CBCT.

In this study, a novel AI system based on deep learning methods was evaluated to determine its real-time performance of CBCT imaging diagnosis of anatomical landmarks, pathologies, clinical effectiveness, and safety when used by dentists in a clinical setting. The system consists of 5 modules: ROI-localization-module (segmentation of teeth and jaws), tooth-localization and numeration-module, periodontitis-module, caries-localization-module, and periapical-lesion-localization-module. These modules use CNN based on state-of-the-art architectures. In total, 1346 CBCT scans were used to train the modules. After annotation and model development, the AI system was tested for diagnostic capabilities of the Diagnocat AI system. 24 dentists participated in the clinical evaluation of the system. 30 CBCT scans were examined by two groups of dentists, where one group was aided by Diagnocat and the other was unaided. The results for the overall sensitivity and specificity for aided and unaided groups were calculated as an aggregate of all conditions. The sensitivity values for aided and unaided groups were 0.8537 and 0.7672 while specificity was 0.9672 and 0.9616 respectively. There was a statistically significant difference between the groups (p = 0.032). This study showed that the proposed AI system significantly improved the diagnostic capabilities of dentists.

Assessment of the efficiency of a pre- versus post-acquisition metal artifact reduction algorithm in the presence of 3 different dental implant materials using multiple CBCT settings: An in vitro study.

PURPOSE: The aim of this study was to assess artifacts generated in cone-beam computed tomography (CBCT) of 3 types of dental implants using 3 metal artifact reduction (MAR) algorithm conditions (pre-acquisition MAR, postacquisition MAR, and no MAR), and 2 peak kilovoltage (kVp) settings. MATERIALS AND METHODS: Titanium-zirconium, titanium, and zirconium alloy implants were placed in a dry mandible. CBCT images were acquired using 84 and 90 kVp and at normal resolution for all 3 MAR conditions. The images were analyzed using ImageJ software (National Institutes of Health, Bethesda, MD) to calculate the intensity of artifacts for each combination of material and settings. A 3-factor analysis of variance model with up to 3-way interactions was used to determine whether there was a statistically significant difference in the mean intensity of artifacts associated with each factor. RESULTS: The analysis of all 3 MAR conditions showed that using no MAR resulted in substantially more severe artifacts than either of the 2 MAR algorithms for the 3 implant materials; however, there were no significant differences between pre- and post-acquisition MAR. The 90 kVp setting generated less intense artifacts on average than the 84 kVp setting. The titanium-zirconium alloy generated significantly less intense artifacts than zirconium. Titanium generated artifacts at an intermediate level relative to the other 2 implant materials, but was not statistically significantly different from either. CONCLUSION: This in vitro study suggests that artifacts can be minimized by using a titanium-zirconium alloy at the 90 kVp setting, with either MAR setting.

Do Ultra-Low Multidetector Computed Tomography Doses and Iterative Reconstruction Techniques Affect Subjective Classification of Bone Type at Dental Implant Sites?

PURPOSE: To investigate whether ultra-low-dose multidetector computed tomography (MDCT) combined with the reconstruction techniques filtered backprojection (FBP), adaptive statistical iterative reconstruction (ASIR), or model-based iterative reconstruction (MBIR) alters the subjective classification of revised Lekholm and Zarb (LZ) bone types at prospective dental implant sites. MATERIALS AND METHODS: Three cadavers underwent a reference MDCT examination using a standard dose volume (CT dose index [CTDIvol]: 29.4 mGy) and reconstructed with FBP in addition to five test protocols (LD1-LD5) using ultra-low doses (CTDIvol: 4.19, 2.64, 0.99, 0.53, and 0.29 mGy, respectively) and reconstructed with FBP, ASIR 50, ASIR 100, and MBIR. Transverse cross-sectional images of the jawbones were obtained, and three examiners subjectively classified the bone type in each image using the revised LZ classification. The bone type classifications obtained using the reference examination were compared with those obtained from the test protocols for each examiner, and kappa statistic was used to analyze the level of agreement between the reference and test protocols. The clinical significance of the differences was analyzed with Wilcoxon signed rank test. RESULTS: Examiners 1 and 2 found moderate to strong agreement between the reference and test protocols, while Examiner 3 found strong to almost perfect agreement (P < .001). The Wilcoxon signed rank test did not demonstrate a clinical significance of the differences between the reference and test protocols for any of the three examiners. CONCLUSION: MDCT dose reductions of up to 99% did not significantly alter the subjective classification of bone at dental implant sites.

Temporomandibular Joint Imaging.

The temporomandibular joint (TMJ) is an anatomically and biomechanically complex structure. Understanding how this structure grows and functions is essential to accurate radiographic evaluation. This article discusses the anatomy, function, and growth and development of the TMJ and how growth changes can affect the morphology of the craniofacial structures. Accordingly, the radiographic appearance of the entities that may alter the TMJ are discussed, including developmental, degenerative, inflammatory, and traumatic changes. Both osseous imaging and soft tissue imaging are shown.

Impact of routine open-mouth osseous temporomandibular joint tomography on diagnosis and therapeutic options.

OBJECTIVES: The aim of this study was to evaluate the impact of routine open mouth osseous temporomandibular joint (TMJ) tomography on diagnosis and treatment planning of TMJ conditions. Investigating the need for such images is important to justify the additional radiation exposure imparted by such procedures. STUDY DESIGN: The records of patients who underwent closed- and open-mouth osseous TMJ tomography (planar film tomography up to the beginning of 2006; cone beam computed tomography from 2006 onward) were reviewed. Three examiners formulated a diagnosis and treatment plan based on the history, clinical findings, and tomography interpretation reports of closed-mouth images. Then they reviewed the interpretations of the open-mouth images and recorded whether they would change their original diagnosis and/or treatment plan on the basis of the findings. Descriptive analysis of the results was performed. RESULTS: The impact of routine open-mouth imaging on diagnosis and treatment planning was variable among the examiners. Examiners 1, 2, and 3 had a change in diagnosis in 7%, 5%, and 3% of cases, respectively, and a change in treatment plan in 1%, 1%, and 8%, respectively. CONCLUSIONS: Routine open-mouth osseous TMJ tomography had a minimal impact on diagnosis and treatment planning of TMJ conditions, which varied according to the treating clinician.

Basic principles and applications of (18)F-FDG-PET/CT in oral and maxillofacial imaging: A pictorial essay.

A combination of positron emission tomography (PET) with (18)F-labeled fluoro-2-deoxyglucose ((18)F-FDG) and computed tomography ((18)F-FDG-PET/CT) has increasingly become a widely used imaging modality for the diagnosis and management of head and neck cancer. On the basis of both recent literature and our professional experience, we present a set of principles with pictorial illustrations and clinical applications of FDG-PET/CT in the evaluation and management planning of squamous cell carcinoma of the oral cavity and oropharynx. We feel that this paper will be of interest and will aid the learning of oral and maxillofacial radiology trainees and practitioners.