MRI susceptibility artefacts caused by orthodontic wire.

OBJECTIVES: To evaluate magnetic susceptibility artefacts produced by orthodontic wires on MRI and the influence of wire properties and MRI image sequences on the magnitude of the artefact. METHODS: Arch form orthodontic wires [four stainless steels (SS), one cobalt chromium (CC) alloy, 13 titanium (Ti) alloys] were embedded in a polyester phantom, and scanned using a 1.5-T superconducting magnet scanner with an eight-channel phased-array coil. All wires were scanned with T1-weighted spin echo (SE) and gradient echo (GRE) sequences according to the American Society for Testing and Materials (ASTM) F2119-07 standard. The phantom was also scanned other eight sequences. Artefacts were measured using the ASTM F2119-07 definition and OsiriX software. Artefact volume was analyzed according to metal composition, wire length, number of wires, wire thickness, and imaging sequence as factors. RESULTS: With SE/GRE, black/white artefacts volumes from all SS wires were significantly larger than those produced by CC and Ti wires (P < 0.01). With the GRE, the black artefacts volume was highest with the SS wires. With the SE, the black artefacts volume was small, whereas white artefacts were noticeable. The cranio-caudal extent of the artefacts was significantly longer with SS wires (P < 0.01). Although a direct relationship of wire length, number of wires and wire thickness with artefact volume was noted, these factors did not influence artefact extension in the cranio-caudal direction. CONCLUSIONS: Ferromagnetic/paramagnetic orthodontic wires create artefacts due to local alteration of magnetic field homogeneity. The SS-type wires produced the largest artefacts followed by CC and Ti.

Applying the American Association of Endodontists and American Academy of Oral and Maxillofacial Radiology guidelines for cone-beam computed tomography prescription: Impact on endodontic clinical decisions.

BACKGROUND: The American Association of Endodontists (AAE) and the American Academy of Oral and Maxillofacial Radiology (AAOMR) developed guidelines for the prescription of cone-beam computed tomographic (CBCT) imaging. The impact of appropriately prescribed CBCT imaging on endodontic diagnosis and treatment (Tx) decisions was examined. METHODS: The clinical databases at the School of Dentistry at the University of California, Los Angeles, Los Angeles, California, were queried to identify patients referred for CBCT imaging from the postgraduate endodontic clinic over a consecutive 36-month period. Primary and secondary indications for CBCT imaging were recorded. Pre-CBCT uncertainty in diagnosis, Tx of the teeth in question, and post-CBCT changes to the diagnosis and Tx plan were recorded. RESULTS: CBCT imaging was prescribed for 12% of patients. A total of 442 scans were prescribed to evaluate 526 teeth. Molars accounted for 51% of teeth examined. Overall, CBCT effected a change in periapical diagnosis (21%) and in the Tx plan (69%). The 5 most frequent primary indications for CBCT imaging were, in order, AAE-AAOMR recommendations 7, 9, 2, 12, and 6. The impact of these recommendations on Tx decisions varied from 48% through 93%. CONCLUSIONS: This study validates the use of the AAE-AAOMR guidelines for prescribing CBCT imaging for endodontic evaluations. CBCT imaging contributed predominantly to Tx decisions rather than diagnostic determinations. PRACTICAL IMPLICATIONS: This study validates AAE-AAOMR case selection guidelines for CBCT imaging and shows a positive impact of prescription imaging on endodontic decision making.

Influence of Vitamin D Deficiency on Cyclin D1-Induced Parathyroid Tumorigenesis.

Primary hyperparathyroidism (PHPT) is a common endocrinopathy for which several pathogenic mechanisms, including cyclin D1 overexpression, have been identified. Vitamin D nutritional status may influence parathyroid tumorigenesis, but evidence remains circumstantial. To assess the potential influence of vitamin D insufficiency/deficiency on initiation or progression of parathyroid tumorigenesis, we superimposed vitamin D insufficiency or deficiency on parathyroid tumor-prone parathyroid hormone-cyclin D1 transgenic mice. Mice were placed on diets containing either 2.75 IU/g, 0.25 IU/g, or 0.05 IU/g cholecalciferol, either prior to expected onset of PHPT or after onset of biochemical PHPT. When introduced early, superimposed vitamin D insufficiency/deficiency had no effect on serum calcium or on parathyroid gland growth. However, when introduced after the onset of biochemical PHPT, vitamin D deficiency led to larger parathyroid glands without differences in serum biochemical parameters. Our results suggest that low vitamin D status enhances proliferation of parathyroid cells whose growth is already being tumorigenically driven, in contrast to its apparent lack of direct proliferation-initiating action on normally growing parathyroid cells in this model. These results are consistent with the hypothesis that suboptimal vitamin D status may not increase incidence of de novo parathyroid tumorigenesis but may accelerate growth of a preexisting parathyroid tumor.

Patient shielding during dentomaxillofacial radiography: Recommendations from the American Academy of Oral and Maxillofacial Radiology.

BACKGROUND: The American Academy of Oral and Maxillofacial Radiology established an ad hoc committee to draft evidence-based recommendations and clinical guidance for the application of patient contact shielding during dentomaxillofacial imaging. TYPES OF STUDIES REVIEWED: The committee reviewed monographs and reports from radiation protection organizations and studies that reported radiation dose to gonads, breasts, and thyroid gland from dentomaxillofacial imaging. RESULTS: Considering the absence of radiation-induced heritable effects in humans and the negligible dose to the gonads and fetus from dentomaxillofacial imaging, the committee recommends discontinuing shielding of the gonads, pelvic structures, and fetuses during all dentomaxillofacial radiographic imaging procedures. On the basis of radiation doses from contemporaneous maxillofacial imaging, the committee considered that the risks from thyroid cancer are negligible and recommends that thyroid shielding not be used during intraoral, panoramic, cephalometric, and cone-beam computed tomographic imaging. PRACTICAL IMPLICATIONS: This position statement informs and educates the reader on evolving radiation protection practices and provides simple, unequivocal guidance to dental personnel to implement these guidelines. State and local authorities should be contacted to update regulations to reflect these recommendations.

Reprint of: Prevalence and Characteristics of Root Resorption Identified in Cone-Beam Computed Tomography Scans.

INTRODUCTION: Root resorption is a destructive process that compromises tooth structure and can result in tooth loss. Often it remains asymptomatic and is an incidental finding on radiographic examinations. The purpose of this study was to determine prevalence and characteristics of root resorption in patients referred for cone-beam computed tomography (CBCT) imaging for a variety of indications. METHODS: The study included CBCT scans of 1086 consecutive patients referred for CBCT imaging over an 18-month period. A total of 1148 scans were acquired. Data were abstracted from radiology reports, and prevalence estimates of resorption were computed for the aggregate sample and also across specific indications. RESULTS: Resorption was identified in 171 patients (15.7%, 95% CI: 13.6%-17.9%) and in 249 teeth with a prevalence range of 2.6%-92.3% across specific indications. An 18.7% of the patients had 2 resorption sites whereas 8.8% had 3 or more resorption sites. The majority of affected teeth were anteriors (43.8%), followed by molars (40.6%) and premolars (14.5%). The most prevalent resorption types were external (29.3%), cervical (22.5%), infection-induced apical resorption (13.7%), internal (9.6%), and impacted tooth induced (8.8%). The majority of teeth with resorption did not have prior endodontic treatment (73.9%) and had radiographically normal periapex (69.5%). Of 249 teeth with resorption, 31% presented as incidental finding. The prevalence of incidental findings of resorption increased with age, P < .05, and was significantly lower for anterior teeth (20.2%) as compared to premolars (41.7%) and molars (36.6%), (P < .05). CONCLUSION: The high proportion of incidental findings of resorption detected by CBCT suggests that resorption is not recognized/detected by conventional radiography and therefore remains underdiagnosed.

Recommendations for Imaging of the Temporomandibular Joint. Position Statement from the American Academy of Oral and Maxillofacial Radiology and the American Academy of Orofacial Pain.

This position statement was developed by an ad hoc committee of the American Academy of Oral and Maxillofacial Radiology and the American Academy of Orofacial Pain. The committee reviewed the pertinent literature and drafted recommendations for imaging. This joint statement provides evidence-based recommendations and clinical guidance for applying appropriate diagnostic imaging to evaluate the temporomandibular joint (TMJ). This manuscript guides the design of TMJ imaging examinations, addresses in-office CBCT imaging, and provides timely evidence-based recommendations to evaluate the TMJ bony components, also addressing the use of MRI and other modalities to evaluate TMJ involvement in different pathologic conditions.

Prevalence and Characteristics of Root Resorption Identified in Cone-Beam Computed Tomography Scans.

INTRODUCTION: Root resorption is a destructive process that compromises tooth structure and can result in tooth loss. Often it remains asymptomatic and is an incidental finding on radiographic examinations. The purpose of this study was to determine prevalence and characteristics of root resorption in patients referred for cone-beam computed tomography (CBCT) imaging for a variety of indications. METHODS: The study included CBCT scans of 1086 consecutive patients referred for CBCT imaging over an 18-month period. A total of 1148 scans were acquired. Data were abstracted from radiology reports, and prevalence estimates of resorption were computed for the aggregate sample and also across specific indications. RESULTS: Resorption was identified in 171 patients (15.7%, 95% CI: 13.6%-17.9%) and in 249 teeth with a prevalence range of 2.6%-92.3% across specific indications. An 18.7% of the patients had 2 resorption sites whereas 8.8% had 3 or more resorption sites. The majority of affected teeth were anteriors (43.8%), followed by molars (40.6%) and premolars (14.5%). The most prevalent resorption types were external (29.3%), cervical (22.5%), infection-induced apical resorption (13.7%), internal (9.6%), and impacted tooth induced (8.8%). The majority of teeth with resorption did not have prior endodontic treatment (73.9%) and had radiographically normal periapex (69.5%). Of 249 teeth with resorption, 31% presented as incidental finding. The prevalence of incidental findings of resorption increased with age, P < .05, and was significantly lower for anterior teeth (20.2%) as compared to premolars (41.7%) and molars (36.6%), (P < .05). CONCLUSION: The high proportion of incidental findings of resorption detected by CBCT suggests that resorption is not recognized/detected by conventional radiography and therefore remains underdiagnosed.

MR appearance of a rare ameloblastic fibroma with formation of dental hard tissues with histopathologic correlation: a case report.

An ameloblastic fibroma with formation of dental hard tissues, which the classical name is ameloblastic fibro-odontoma (AFO), is a rare type of mixed odontogenic tumor. An 8-year-old boy was diagnosed with AFO, with an inhomogeneous high signal within the lesion shown by T2-weighted magnetic resonance imaging (MRI). Computed tomography (CT) imaging revealed a unilocular low CT value area of 24 × 19 × 26 mm with buccolingual bony expansion and cortical bone thinning on the left side of the mandible including the crown of the mandibular left second molar. In addition, multiple calcified bodies were detected within the lesion, one of which had a CT value of approximately 2200 HU, equivalent to that of enamel. MRI indicated the lesion to be sized 24 × 19 × 25 mm along with buccolingual bony expansion in the left side of the mandible. Additionally, the lesion showed an internal inhomogeneous high signal, while a portion had an especially high signal in T2-weighted images. That particularly high signal area coincided with the nodular growth area of mucus-rich mesenchymal components without the epithelial component in histopathology findings. The particularly high signal revealed by T2-weighted imaging could be attributed to the mucus-rich component. MRI was found useful for revealing differences in the internal histopathological properties of an AFO in our patient.

Improvements in image quality after optimization in digital intraoral radiographs.

BACKGROUND: Digital intraoral radiographic exposures are optimized largely on the basis of subjective assessment of diagnostic image quality. This study presents an objective approach to optimize radiographic exposure settings for digital intraoral radiographic systems. METHODS: Seven size 2 digital intraoral systems were assessed for image quality and determination of optimal exposure following the protocol specified in American National Standard Institute/American Dental Association Standard No. 1094: Quality Assurance for Digital Intra-Oral Radiographic Systems. A ProX radiograph unit (Planmeca) at 63 kVp and 6 mA was used to obtain radiographs of the Dental Digital Quality Assurance phantom. ImageJ software (National Institutes of Health) was used to quantify dynamic range and spatial resolution, and contrast perceptibility was evaluated visually. Optimal exposure is the setting with the maximal contrast perceptibility and spatial resolution while displaying the full dynamic range. After image optimization, a custom phantom consisting of an endodontically prepared tooth was imaged to evaluate the file position relative to the apex for each system. Differences in distances between file position relative to the root apex at the optimal exposure as well as 1 increment above and below were measured. RESULTS: Radiographic images obtained at the optimal exposure yielded better visualization and more accurate measurements of the file tip relative to the apex. CONCLUSIONS: Optimizing radiographic exposures improves image quality and accuracy in clinical decisions. PRACTICAL IMPLICATIONS: Improvement in image quality and better accuracy in actual distance of the endodontic file to the radiographic apex coupled with complete cleaning, shaping, and obturation of the canal should lead to better endodontic treatment outcomes.

3-Dimensional Craniofacial Imaging: A Template for Systematic Radiologic Evaluation for Alveolar Cleft Assessment and Planning.

BACKGROUND: Imaging findings are central to the diagnosis and treatment planning decisions when managing craniofacial differences. However, limited information is published on protocols for systematic cleft imaging assessment and for effective communication of these findings. SOLUTION: A template is presented to help guide radiologic imaging reports to acquire the relevant clinical information needed to manage patients with alveolar cleft.

Radiation-induced undifferentiated spindle cell sarcoma following high-dose-rate interstitial brachytherapy for tongue squamous cell carcinoma.

High-dose-rate interstitial brachytherapy (HDR-ISBT) has recently come to be considered one of the most effective treatments for oral cancer. On the other hand, it is important to note that radiation therapy has some side effects. Especially, radiation-induced malignancy is probably the most serious complication affecting long-term survivors. We report a case of a radiation-induced undifferentiated spindle cell sarcoma that developed following HDR-ISBT for tongue squamous cell carcinoma (SCC). A 39-year-old woman with right tongue SCC underwent HDR-ISBT (60 Gy, 10 fractions, 8 days) treatment. Five years and one month later, a tumor had developed at the primary site. Surgery was performed for the tumor, which was histopathologically diagnosed as an undifferentiated spindle cell sarcoma. That was distinct from the squamous cell origin of the primary cancer. According to recently established criteria for radiation-induced malignancy, this case was classified as a radiation-induced sarcoma. A search of the literature revealed no previous report of radiation-induced malignancy following HDR-ISBT for tongue cancer.

Recommendations for imaging of the temporomandibular joint. Position statement from the American Academy of Oral and Maxillofacial Radiology and the American Academy of Orofacial Pain.

This position statement was developed by an ad hoc committee of the American Academy of Oral and Maxillofacial Radiology and the American Academy of Orofacial Pain. The committee reviewed pertinent literature and drafted recommendations for imaging. The statement provides evidence-based recommendations and clinical guidance to apply appropriate diagnostic imaging to evaluate the temporomandibular joint.

Clinical evaluation of Er,Cr:YSGG laser therapy used as an adjunct to non-surgical treatment of periodontitis: Twelve-month results from a pilot study.

BACKGROUND: The purpose of this study was to evaluate the results of adjunctive Er,Cr:YSGG laser therapy with scaling and root planing (SRP) as compared with SRP alone in the treatment of moderate to severe periodontitis. METHODS: Fifteen adults (aged 27 to 65 years) with 90 nonadjacent sites probing ≥ 5 mm were treated in split-mouth design with SRP and laser therapy versus SRP alone. Probing pocket depth (PPD), gingival recession (GR), clinical attachment level (CAL), plaque, and bleeding on probing were collected at baseline, 1, 3, 6, 9, and 12 months. Patient reported outcomes were measured to assess pain, sensitivity, and satisfaction. RESULTS: Clinical improvements were similar for test and control sites with no statistically significant difference. At 12 months, the average PPD reduced from 6.1 to 4.2 mm for test and 6.2 to 4.3 mm for control sites. GR increased by 0.4 mm at test and control sites. CAL increased from 6.8 to 5.3 mm for test and 6.9 to 5.5 mm for control sites. Clinical outcomes were stratified by baseline PPD ( = 5, = 6 and ≥7 mm) and analyzed for number of sites that reduced (≤4 mm). No significant difference was observed when the baseline PPD was 5 or 6 mm. Test sites with baseline PPD ≥7 mm demonstrated a statistically significant difference in the percentage of reduced sites when compared with controls at nine (P = 0.001) and 12 months (P = 0.044). CONCLUSIONS: Adjunctive Er,Cr:YSGG laser therapy with SRP provides similar clinical improvement in the treatment of moderate-severe periodontitis as SRP alone and may offer some advantage for deeper (≥7 mm) pockets.

Prognostic factors for lymph node metastasis from upper gingival carcinomas.

OBJECTIVES: This study sought to identify tumor characteristics that associate with regional lymph node metastases in squamous cell carcinomas originating in the upper gingiva. MATERIALS AND METHODS: Data from 113 patients from Osaka University Dental Hospital were included. We measured each primary tumor's width, length, depth, and the extent of bone invasion. Additionally, tumor signal intensity for T1 and T2-weighted images as well as the center of the tumor's location and T classification was assessed, and a histopathological analysis was performed. RESULTS: Tumor signal intensity was not found to be a significant prognostic factor. However, bucco-lingual width, histopathological classification as well as the tumor's location were significantly different between metastatic and non-metastatic groups in both univariate and multivariate analysis. Superior-inferior depth and T classification were significant only in the univariate (and not the multivariate) analysis. CONCLUSIONS: Bucco-lingual width, histopathological grading as well as the tumor's location are likely to be important predictors for the occurrence of LN metastasis in upper gingival carcinoma patients and should be considered when managing care for these patients.

Diffusion-weighted magnetic resonance imaging of the oral and maxillofacial region: optimal fat suppression method.

OBJECTIVE: To compare 3 fat suppression methods-water excitation (WE), chemical shift selective (CHESS), and short T1 inversion recovery (STIR)-for optimal image quality and apparent diffusion coefficient (ADC) values with magnetic resonance imaging (MRI) using diffusion-weighted imaging (DWI) of the oral and maxillofacial region. STUDY DESIGN: In total, 53 patients with 73 lesions were enrolled in this study. MRI using DWI protocols with the 3 fat suppression methods were performed in addition to a conventional MRI protocol. The diagnostic image quality of lesions, image uniformity, degree of image artifacts, and ADC values of the lesions were evaluated. Average visual scores and ADC values were compared, and post hoc pairwise comparisons were performed, with the level of significance set at P < .0167. RESULTS: Diagnostic image quality was not significantly different among the fat suppression methods (P ≥ .042). Image uniformity was significantly higher (P < .001), and the degree of image artifacts was significantly lower (P < .001), in images using the STIR method. Mean ADC values did not differ significantly among the 3 methods. CONCLUSIONS: The STIR method was the most useful fat suppression method for DWI of the oral and maxillofacial region because of its high level of image uniformity and few image artifacts.

Zygomaticomaxillary modifications in the horizontal plane induced by micro-implant-supported skeletal expander, analyzed with CBCT images.

BACKGROUND: Miniscrew-assisted rapid palatal expansion (MARPE) has been adopted in recent years to expand the maxilla in late adolescence and adult patients. Maxillary Skeletal Expander (MSE) is a device that exploits the principles of skeletal anchorage to transmit the expansion force directly to the maxillary bony structures and is characterized by the miniscrews' engagement of the palatal and nasal cortical bone layers. In the literature, it has been reported that the zygomatic buttress is a major constraint that hampers the lateral movement of maxilla, since maxilla is located medially to the zygomatic arches. The objective of the present study is to analyze the changes in the zygomatic bone, maxillary bone, and zygomatic arches and to localize the center of rotation for the zygomaticomaxillary complex in the horizontal plane after treatment with MSE, using high-resolution cone-beam computed tomography (CBCT) images. METHODS: Fifteen subjects with a mean age of 17.2 (± 4.2) years were treated with MSE. CBCT records were taken before and after miniscrew-assisted maxillary expansion; three linear and four angular parameters were identified in the axial zygomatic section (AZS) and were compared from pre-treatment to post-treatment using the Wilcoxon signed rank test. RESULTS: Anterior inter-maxillary distance increased by 2.8 mm, posterior inter-zygomatic distance by 2.4 mm, angle of the zygomatic process of the temporal bone by 1.7° and 2.1° (right and left side) (P < 0.01). Changes in posterior inter-temporal distance and zygomaticotemporal angle were negligible (P > 0.05). CONCLUSIONS: In the horizontal plane, the maxillary and zygomatic bones and the whole zygomatic arch were significantly displaced in a lateral direction after treatment with MSE. The center of rotation for the zygomaticomaxillary complex was located near the proximal portion of the zygomatic process of the temporal bone, more posteriorly and more laterally than what has been reported in the literature for tooth-borne expanders. Bone bending takes place in the zygomatic process of the temporal bone during miniscrew-supported maxillary expansion.

Radiographic predictors of bone exposure in patients with stage 0 medication-related osteonecrosis of the jaws.

OBJECTIVE: The aim of this study was to explore the radiographic appearance of stage 0 medication-related osteonecrosis of the jaws (MRONJ) and examine 5 radiographic parameters (trabecular sclerosis, cortical erosion, periosteal reaction, sequestration, and crater-like defect) as predictors of progression to bone exposure. STUDY DESIGN: Twenty-three patients with a history of antiresorptive therapy, no bone exposure, and nonspecific signs and symptoms were included. Intraoral photographs, panoramic and cone beam computed tomography (CBCT) images at initial visit, and follow-up intraoral photographs were reviewed. Three patients had dental disease (DD), 10 patients with stage 0 MRONJ did not progress to bone exposure (NBE), and 10 patients progressed to bone exposure (BE). Radiographic parameters were scored as absent (0), localized (1), or extensive (2), and their sum formed the composite radiographic index (CRI). RESULTS: DD patients demonstrated minimal radiographic findings, and their CRI was significantly lower than that of NBE and BE patients. Additionally, BE patients demonstrated a higher radiographic index compared with NBE patients. Intriguingly, sequestration was observed in the initial CBCT of 9 (90%) of 10 BE patients, whereas 80% of NBE patients showed absence of sequestration at initial CBCT examination. CONCLUSIONS: CBCT imaging can aid in the differentiation of stage 0 MRONJ from dental disease. Radiographic sequestration at initial presentation can serve as a predictor of future bone exposure in patients with stage 0 MRONJ.

Midfacial changes in the coronal plane induced by microimplant-supported skeletal expander, studied with cone-beam computed tomography images.

INTRODUCTION: Our objectives were to evaluate midfacial skeletal changes in the coronal plane and the implications of circummaxillary sutures and to localize the center of rotation for the zygomaticomaxillary complex after therapy with a bone-anchored maxillary expander, using high-resolution cone-beam computed tomography. METHODS: Fifteen subjects with a mean age of 17.2 ± 4.2 years were treated with a bone-anchored maxillary expander. Pretreatment and posttreatment cone-beam computed tomography images were superimposed and examined for comparison. RESULTS: Upper interzygomatic distance increased by 0.5 mm, lower interzygomatic distance increased by 4.6 mm, frontozygomatic angles increased by 2.5° and 2.9° (right and left sides), maxillary inclinations increased by 2.0° and 2.5° (right and left sides), and intermolar distance increased by 8.3 mm (P <0.05). Changes in frontoethmoidal, zygomaticomaxillary, and molar basal bone angles were negligible (P >0.05). CONCLUSIONS: A significant lateral displacement of the zygomaticomaxillary complex occurred in late adolescent patients treated with a bone-anchored maxillary expander. The zygomatic bone tended to rotate outward along with the maxilla with a common center of rotation located near the superior aspect of the frontozygomatic suture. Dental tipping of the molars was negligible during treatment.