Musculoaponeurotic architecture of the human masseter muscle: an in vivo ultrasonographic study of architectural changes during mandibular protrusion and lateral excursions.

OBJECTIVE: The present study evaluated the in vivo musculoaponeurotic architecture of the superficial head (SH) of the masseter muscle (MM) of asymptomatic participants in excursive mandibular movements compared to the relaxed state as examined with ultrasonography. It was hypothesized that the mean fiber bundle length (FBL) and mean height of the aponeurosis (HA) of the laminae of the SH would differ significantly between the relaxed state and protrusion, ipsilateral excursion, and contralateral excursion. STUDY DESIGN: The MM was studied volumetrically in 12 female and 12 male asymptomatic participants bilaterally by using ultrasound imaging. Mean FBL and HA in protrusion and ipsilateral and contralateral excursion were compared to these values in the relaxed state using paired t tests (P < .05). The intraclass correlation coefficient was used to assess intraexaminer reliability. RESULTS: The SH exhibited multiple laminae. Fiber bundles were found to attach to bone and the superior and inferior aponeuroses. Mean FBL was significantly shorter and mean HA significantly longer in protrusion and the excursions than in the relaxed state although the pattern of altered laminae and aponeuroses differed among the mandibular movements. Intraexaminer reliability was excellent. CONCLUSION: Specific changes in mean FBL and mean HA suggest differential contraction of the SH of the MM based on laminar morphology. These findings provide a baseline to investigate musculoaponeurotic changes in patients with myogenic masseter muscle pain.

Interactive computer-assisted learning as an educational method for learning pediatric interproximal dental caries identification.

OBJECTIVE: We developed a web-based tool to measure the amount and rate of skill acquisition in pediatric interproximal caries diagnosis among pre- and postdoctoral dental students and identified variables predictive for greater image interpretation difficulty. STUDY DESIGN: In this multicenter prospective cohort study, a convenience sample of pre- and postdoctoral dental students participated in computer-assisted learning in the interpretation of bitewing radiographs of 193 children. Participants were asked to identify the presence or absence of interproximal caries and, where applicable, locate the lesions. After every case, participants received specific visual and text feedback on their diagnostic performance. They were requested to complete the 193-case set but could complete enough cases to achieve a competency performance standard of 75% accuracy, sensitivity, and specificity. RESULTS: Of 130 participants, 62 (47.7%) completed all cases. The mean change from initial to maximal diagnostic accuracy was +15.3% (95% CI, 13.0-17.7), sensitivity was +10.8% (95% CI, 9.0-12.7), and specificity was +15.5% (95% CI, 12.9-18.1). The median number of cases completed to achieve competency was 173 (interquartile range, 82-363). Of these 62 participants, 45 (72.6%) showed overall improvement in diagnostic accuracy. Greater numbers of interproximal lesions (P < .001) and the presence of noninterproximal caries (P < .001) predicted greater interpretation difficulty. CONCLUSIONS: Computer-assisted learning led to improved diagnosis of interproximal caries on bitewing radiographs among pre- and postdoctoral dental students.

Optimizing effective dose and image quality in cone beam CT sialography.

OBJECTIVES: The purpose of this study was to develop protocols that optimize patient radiation dose and image quality for cone beam computed tomographic (CBCT) sialography for the major salivary glands. STUDY DESIGN: Radiation absorbed dose measurements were repeated in triplicate using 25 sites in the head and neck of a Radiation ANalog DOsimetry system (RANDO) phantom, and effective doses were calculated across a range of peak kilovoltage (kVp) and milliamperage (mA) settings using an 8 cm (diameter) by 5 cm (height) field of view (FOV) for submandibular imaging and an 8 cm (diameter) by 8 cm (height) FOV for parotid imaging. Image signal difference-to-noise ratio (SDNR) was determined, and the figure-of-merit (FOM), a measure of image quality, was calculated. RESULTS: For submandibular sialography, 85 kVp and 6 mA were chosen as the optimal exposure parameters, resulting in a mean effective dose of 82.47 µSv and a mean SDNR of 13.86, with a mean FOM of 2.33 µSv-1. For parotid sialography, 70 kVp and 6 mA were chosen, and these settings resulted in a mean effective dose of 39.99 µSv, a mean SDNR of 17.43, and a mean FOM of 7.60 µSv-1. CONCLUSIONS: Low-dose 3-dimensional sialography with high image quality and minimal effective dose can be delivered using CBCT with localized, small FOVs.

Computed tomographic imaging features of maxillary and mandibular melanotic neuroectodermal tumor of infancy: Report of 2 cases and systematic review.

OBJECTIVE: The aim of this systematic review was to determine the computed tomographic (CT) imaging characteristics of maxillary and mandibular melanotic neuroectodermal tumor of infancy (MNTI). Two cases from our institution were also presented. STUDY DESIGN: Full-text case reports and case series of histopathologically proven gnathic MNTI with CT figures of diagnostic quality were searched in PubMed, Scopus, Web of Science, Ovid, and Google Scholar databases from July 2021 to February 2022. Descriptive statistics were used to determine the frequency of each CT feature of gnathic MNTI. RESULTS: Fifty-two published studies met the eligibility criteria, providing a total of 53 maxillary and mandibular MNTIs for analysis. In order of frequency, the CT features of gnathic MNTI that were present in over half of the study sample were bone expansion (53, 100%), a well-defined periphery (49, 92.5%), tooth displacement (45, 84.9%), and a bilocular radiolucent internal pattern (32, 60.4%). CONCLUSIONS: The bilocular radiolucent internal pattern has not been recognized as a common CT feature of gnathic MNTI. When associated with a well-defined, expansile mass in the infantile maxilla or mandible, this imaging characteristic can support a radiologic interpretation of MNTI.

A dynamic ultrasonographic in vivo study of the musculoaponeurotic architecture of the human masseter muscle.

OBJECTIVE: In the present study, we sought to investigate the in vivo musculoaponeurotic architecture of the masseter muscle (MM) volumetrically with ultrasound in asymptomatic participants. It was hypothesized that the mean fiber bundle length (FBL) and mean aponeurotic height of laminae of the MM differ significantly between the relaxed state and maximally contracted state upon elevation of the mandible. STUDY DESIGN: The MM was investigated volumetrically in 12 male and 12 female asymptomatic participants (mean age, 25.8 ± 4.1 years) using ultrasound. The mean FBL and mean height of aponeuroses in the relaxed and maximally contracted states were compared using paired t tests, with significance established at P ≤ .05. Intrarater reliability was assessed using the intraclass correlation coefficient (ICC). RESULTS: The MM consisted of the superficial head (SH) and deep head, each arranged in multiple laminae. Fiber bundles extended between superior and inferior aponeuroses and/or bone. Statistically significant differences (P ≤ .05) were observed in mean FBL and in mean height of aponeuroses between the relaxed and contracted states only in superficial laminae of the SH. CONCLUSIONS: These results suggest there is differential contraction of the laminae of the MM in the transition from relaxed to contracted states. Future comparison with pathologic patients can be made on the basis of an established normative database.

Important radiographic features in the identification of osseous dysplasia-related osteomyelitis.

OBJECTIVES: The aims of this study were to identify radiographic features that distinguish osseous dysplasia-related osteomyelitis (OD-related OM) from OD without OM and to detect possible causes of OD-related OM. STUDY DESIGN: Seventeen OD cases with and without OM were examined on planar and volumetric (cone beam computed tomography or multidetector computed tomography) imaging. Cases were divided into 3 groups based on clinical data: symptomatic OM, incidental (asymptomatic) OM, and control (OD without OM). Images were reviewed by 3 precalibrated observers, blinded to clinical information, for OD characteristics (location and extent); radiographic features of OD-related OM; and possible causes. Radiographic features of OD-related OM chosen by at least 2 observers were statistically analyzed within and between groups. RESULTS: Discontinuity of the cortical plates, widening of the radiolucent rim, decreased attenuation of the radiolucent rim, and sequestrum formation were significantly more common in symptomatic and incidental OM groups than in the control group (P ≤ .05). Two causes, atrophy of the edentulous ridge and presence of a periapical lesion, were also correlated with OD-related OM (P ≤ .05, P ≤ .01, respectively). CONCLUSIONS: Radiographic features can distinguish OD-related OM from OD. Familiarity with these radiographic features and possible causes may help improve the identification of secondarily infected OD.

The effects of physical photostimulable phosphor plate artifacts on the radiologic interpretation of periapical inflammatory disease.

OBJECTIVE: To evaluate how physical photostimulable phosphor (PSP) plate artifacts, such as those created by scratches, phosphor degradation, and surface peeling, affect the radiologic interpretation of periapical inflammatory disease. STUDY DESIGN: A novel technique was developed to digitally superimpose 25 real PSP artifact masks over 100 clinical complementary metal oxide semiconductor (CMOS) periapical images with known radiologic interpretations. These images were presented to 25 general dentists, who were asked to state their radiologic interpretations, their confidence in their interpretations, and their opinions on whether the plates should be discarded. Statistical analyses were conducted by using random intercept mixed models for repeated measures and χ2 tests of the pooled data. RESULTS: No statistically significant adverse effect on interpretation was seen, even at severe artifact levels. There was a statistically significant decrease in the clinicians' confidence and an increase in discard proportions when interpreting images with severe PSP plate artifacts (P < .05). CONCLUSIONS: Although diagnostic efficacy was unaffected, clinicians' confidence decreased and proportionally more clinicians opted to discard sensors when interpreting images with severe artifacts. Future studies on the effects of artifacts on the efficacy of diagnosis of other dental diseases are recommended. Ultimately, these results can guide recommendations for PSP plate quality assurance.

Mandibular changes on panoramic imaging after head and neck radiotherapy.

OBJECTIVES: Changes to the radiographic appearance of the jaws after head and neck radiotherapy have not been thoroughly characterized. This retrospective study examines changes to the appearance of the mandible on panoramic images following intensity-modulated radiotherapy (IMRT) and relates these changes to medical co-morbidities and radiation dose. STUDY DESIGN: The medical and dental charts, and panoramic images of 126 patients who received IMRT at the Princess Margaret Hospital between January 1, 2005, and December 31, 2008, were analyzed independently by three observers. RESULTS: Of the 126 patients, 75 (60%) had post-IMRT changes, as seen on panoramic images; most, 66 (88%), consisted of widened periodontal ligament space (WPLS). The median time to WPLS was 29 months after IMRT. Female gender and radiation dose correlated with decreased time to WPLS. CONCLUSIONS: These results indicate that WPLS is a common radiographic sequela after head and neck radiotherapy, underscoring its clinical significance as a reliable marker of irradiated bone. Furthermore, this type of WPLS needs to be differentiated from odontogenic inflammatory disease and cancer recurrence to avoid unnecessary treatment that may precipitate osteoradionecrosis.

The effects of voxel size on cone beam computed tomography images of the temporomandibular joints.

OBJECTIVES: This clinical study assesses the effect of cone beam computed tomography (CBCT) voxel size on the ability to detect osseous changes associated with degenerative disease of the temporomandibular joint (TMJ). The effect of voxel size on perceived CBCT image quality is also evaluated. STUDY DESIGN: Twenty-two patients presenting for TMJ imaging with suspected degenerative disease were imaged with the Carestream 9000 CBCT unit, using separate right and left joint acquisitions (n = 44). Images were archived at native and downsampled voxel resolutions of 76 µm and 300 µm, respectively. Three oral and maxillofacial radiologists evaluated the images for osseous changes, as well as image quality by using a visual analog scale. RESULTS: There was no statistically significant difference between the voxel sizes in the detection of TMJ osteoarthritic changes. The mean visual analog scale response did, however, differ significantly between the two groups (P = .02). CONCLUSIONS: Despite no improvement in diagnostic efficacy with a smaller voxel size, perceived image quality is consistently higher for images with greater spatial resolution.

Interpretation of panoramic radiographs.

Panoramic radiography has become a commonly used imaging modality in dental practice and can be a valuable diagnostic tool in the dentist's armamentarium. However, the panoramic image is a complex projection of the jaws with multiple superimpositions and distortions which may be exacerbated by technical errors in image acquisition. Furthermore, the panoramic radiograph depicts numerous anatomic structures outside of the jaws which may create additional interpretation challenges. Successful interpretation of panoramic radiographs begins with an understanding of the normal anatomy of the head and neck and how it is depicted in this image type. This article will describe how osseous structures, soft tissues, air spaces and ghost shadows contribute to the final panoramic image. A systematic and repeated approach to examining panoramic radiographs, which is recommended to ensure that critical findings are not overlooked, is also outlined. Examples of challenging interpretations, including variations of anatomy, artefacts and disease, are presented to illustrate these concepts.

A retrospective analysis of referral patterns for oral radiologic consultation over 3 years in Ontario, Canada.

OBJECTIVES: To determine the types of practitioners who most commonly refer and the film type and diagnostic entities that are most frequently submitted for oral radiologic consultation in Ontario, Canada. STUDY DESIGN: A total of 430 referral letters and responses from 2 Ontario oral radiologists from 2003 to 2005 were analyzed. Data collected included the specialty of the referring practitioner, the film type(s) submitted, the radiographic density of the entity of interest, and the interpretation by the radiologist. RESULTS: General practitioners (58.9%) and oral surgeons (21.5%) were the most frequently referring practitioner types, representing 1.2% and 17.1% respectively of each group practicing in Ontario. Also, 18.2% of oral pathologists referred. Panoramic radiographs (79.5%) were included in referrals more often than intraoral radiographs (46.0%). Of the entities, 37.0% were radiopacities, 27.4% were radiolucencies, and 13.5% had mixed radiopaque-radiolucent density. The radiologists interpreted normal features (55.6%) most often. CONCLUSION: Panoramic radiographs with normal findings were submitted to oral radiologists for consultation most frequently in Ontario.