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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., (Copyright © 2016 Elsevier Inc. All rights reserved.)

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., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Central giant cell granuloma (CGCG) is a benign intraosseous lesion. The true nature of this lesion is controversial and remains unknown; the three competing theories are that it could be a reactive lesion, a developmental anomaly or a benign neoplasm. Furthermore, the actual aetiology of CGCG is still unclear, although inflammation, haemorrhage and local trauma have all been suggested; it has also been hypothesized that CGCG may have a genetic aetiology. Lesions central to the mandibular condylar head are very rare, with only three documented cases in the English language literature, none of which elaborates on the CT features. In this case report, a 31-year-old male patient complaining of a left pre-auricular mass underwent radiographic investigation. CT images revealed a lesion central to the mandibular condyle and demonstrated features that were highly suggestive of CGCG. The patient underwent surgical curettage, and the subsequent histopathological examination confirmed the diagnosis of CGCG. 3 years after the procedure the patient presented with a recurrence and underwent complete resection of the mandibular condyle with immediate reconstruction. This report presents CT characteristics of a rare occurrence of CGCG of the mandibular condyle, compares it with other published cases and poses the question of the role of radiology in predicting the degree of aggressive behaviour of these lesions before surgery.

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., (Copyright (c) 2010 Mosby, Inc. All rights reserved.)

A case of Gorham's disease in the maxilla of a 56-year-old male patient is described. The clinical presentation, radiographic and histopathological features and treatment are presented. A discussion of the current understanding of this rare disease, based on review of the literature, is offered.

Objectives: This retrospective study reviews the occurrence of keratocystic odontogenic tumours (KOTs) in nevoid basal cell carcinoma syndrome (NBCCS) patients seen in the Oral and Maxillofacial Radiology Special Procedures Clinic in the Faculty of Dentistry at the University of Toronto., Methods: This study examines the number and radiographic features of KOTs identified in 11 NBCCS patients who presented with 43 KOTs between January 1989 and 30 June 2007 on plain film radiographs and CT., Results: Regression analysis revealed a statistically significant (P < 0.01) relationship between the age at first KOT occurrence and the total number of lifetime KOTs (r = -0.78). Of the KOTs identified, 25 developed in the mandible and 18 developed in the maxillae. The majority of these were associated with a change in either the size or shape of the follicular space, and both plain film radiography and CT were equally effective at demonstrating these changes. CT was, however, more effective at demonstrating endosteal scalloping of cortical bone than plain film radiography (P < 0.001) while the opposite was true for showing tooth displacement (P < 0.01). For patients imaged with both plain radiography and CT (29 KOTs), 5 KOTs were detectable only by CT., Conclusions: Our results suggest that there should be early and frequent monitoring of NBCCS patients for the development of KOTs in youth and adolescence, and that CT imaging should play an important role in these investigations.

During the last decades, an exciting new array of imaging modalities, such as digital imaging, CT, MRI, positron emission tomography, and cone-beam CT (CBCT), has provided astounding new images that continually contribute to the accuracy of diagnostic tasks of the maxillofacial region. The most recent, cone-beam imaging, is gaining rapid acceptance in dentistry because it provides cross-sectional imaging that is often a valuable supplement to intraoral and panoramic radiographs. The information content in such examinations is high and the dose and costs are low. The increasing trend toward the use of CBCT in dental offices may be expected to result in improved diagnosis, but with increased patient dose and health care costs. Using CBCT as a secondary imaging tool helps optimize health-to-risk ratio.

Aim: The prevalence of apical periodontitis (AP) and the quality of root fillings and restorations were determined in two Canadian populations differing in avail-ability of endodontists., Methodology: Radiographs of first-time university patients aged 25-40 years in Toronto and Saskatoon were examined for missing teeth, presence and standard of root fillings, standard of restoration, and AP according to the Periapical Index. Patients with root-filled teeth were invited for clinical examination and interview to inspect the restorations, and to reveal the providers of endodontic treatment and reasons for extractions of missing teeth. Chi-square and independent t-tests interpreted at the 5% significance level were used to examine associations between the prevalence of AP in root-filled teeth and the standard of the root filling, restoration, and providers of treatment., Results: Proportion of patients with root-filled teeth was significantly higher (P < 0.001) in Toronto than in Saskatoon (39 and 26%, respectively). Presence of AP about root-filled teeth (44% in Toronto, 51% in Saskatoon) was significantly associated with poor density (OR = 2.7) short (OR = 2.4) and long (OR = 2.8) root fillings, and with poor radiographic quality of the restoration (OR = 1.7) Prevalence of AP did not differ significantly between teeth treated by generalists and endodontists., Conclusions: The prevalence of AP in root-filled and untreated teeth was comparable to that reported in previous methodologically compatible studies. The quality of both the root filling and the restoration were found to impact on the periapical health of root-filled teeth, with the impact of the restoration being most critical when the quality of the root filling was adequate.

Purpose: This article reviews the literature on radiographic imaging techniques and image interpretation for dental implant treatment., Materials and Methods: MEDLINE was used to identify published peer-reviewed literature for this report., Results: Radiographic images are indispensable in the evaluation of osseous structures when planning treatment for dental implants. Potential bone sites for implant placement can be assessed clinically by means of palpation or probing through the mucosa; however, diagnostic imaging provides the best means for indirectly measuring bone dimensions. After healing of the implant site, the application of radiology is useful to verify the amount of bone adjacent to the implant and that the transmucosal abutments fit the implant. Upon completion of the implant prosthesis, radiology may be used to monitor initial and long-term success of implant treatment., Conclusion: Recommendations for the application of radiology over the course of treatment are made for various implant cases ranging from the overdenture to the single-tooth implant.

Oral and maxillofacial radiology is a dynamic and multifaceted discipline that plays a critical role in patient care, the education of general dentists and dental specialists, and the academic health of the dental school. Diagnostic and treatment advances in temporomandibular joint disorders (TMD), implants trauma and orthognathic surgery, and craniofacial abnormalities depend heavily on conventional and advanced imaging techniques. Oral and maxillofacial radiology contributes to the education of pre- and post-doctoral dental students with respect to biomedical and clinical knowledge, cognitive and psychomotor skills, and the professional and ethical values necessary to properly prescribe, obtain, and interpret radiographs. The development of an active and successful oral and maxillofacial radiology department, division, or section requires the committment of institutional resources. This document may serve as a guide to dental schools committed to excellence in oral and maxillofacial radiology.

Objectives: The purpose of this study was to assess the influence of additional caries and restorations on the detection of caries on the same radiograph., Study Design: Six participants examined five series of four radiographs in which natural carious lesions were present. Each series consisted of the same image with progressively more restorative treatment digitally painted on. The films were randomly presented to the observers who examined the films for the presence and depth of carious lesions. The observers were not informed that the 20 films were disguised versions of the same original five radiographs., Results: The number of carious lesions reported by the six observers did not increase despite the apparent increased restorative intervention viewed on the radiographs., Conclusions: The complexity of restorative care does not affect observers' ability to correctly detect approximal carious lesions.

Objective: The question of whether dentists who most frequently identify tooth surfaces for definite restoration perceive dental caries as significantly deeper than other dentists is assessed., Methods: One group of 20 dentists independently examined 145 unrestored approximal tooth surfaces on 16 bitewing radiographs and recorded their restorative and depth decisions. Another group of 15 dentists similarly scored 304 unrestored surfaces on 30 bitewing radiographs. Each group of dentists was later divided into four subgroups according to the number of surfaces designated for definite restoration by each dentist., Results: As the number of tooth surfaces designated for definite restoration increased, mean caries depth (P < .05 for the high vs low subgroups) and the percent of dentinally carious surfaces increased, while the percent of surfaces assessed as sound decreased. Dentists with the lower numbers of surfaces designated for definite restoration came closest to the true histologic mean caries depth of the examined tooth surfaces., Conclusions: Dentists who designated high numbers of approximal tooth surfaces for definite restoration assessed caries as deeper than other dentists, and deeper than was proven histologically.

The purpose of the study was to analyze the radiographic features of segmental odontomaxillary dysplasia by studying the radiographs of 12 new cases. With a standard data collection form, the radiographic characteristics were assessed by the two principal investigators who studied available radiographs of all cases. As in previously reported cases, abnormal findings in all patients were confined to the posterior segment of one maxilla. The most common findings in the cases studied were sclerosis and thickening of bony trabeculae, missing permanent premolar teeth, abnormal spacing of primary molars vertical orientation of bony trabeculae, a smaller maxillary sinus, and delayed eruption of permanent posterior teeth. Less commonly observed features were enlarged crowns, roots, and pulps of primary molars, irregular resorption of primary molar roots, mediolateral expansion of the alveolar process, splayed roots of primary molars, and an abnormal medial position of the teeth.

Objective: To determine the frequency of specific characteristics of chronic sclerosing osteomyelitis (CSO) of the mandible in plain films compared with CT scans., Methods: After calibration, three observers studied 13 cases of plain films and 11 sets of separated and masked CT scans from the same cases. Controls consisted of cases of fibro-osseous disease with a similar appearance. Comparison with the results of nuclear scans of eight of the cases was made., Results: Periosteal new bone formation, sclerosis and bone enlargement were the most common characteristics. When the CT scans were analysed, detection of sequestra improved from 45 to 91%. There was greater agreement between observers when analysing CT scans compared with plain films. The results of the gallium scans supported the diagnosis in only two of the eight cases., Conclusion: In this study, the CT scans were the most reliable imaging method for revealing characteristics such as sequestra which are useful for the diagnosis of CSO.

The radiographs of 10 cases with a diagnosis of neurofibromatosis involving the mandible were evaluated by two reviewers to document common radiographic characteristics. The most common findings included increase in bone density, enlarged mandibular foramen, lateral bowing of the mandibular ramus, increase in dimensions of the coronoid notch, and a decrease in the mandibular angle. The six cases for which computed tomography scans were available, enlargement of the mandibular foramen and concavity of the medial surface of the ramus were seen. In five of these cases, there was no associated tumor mass adjacent to the concavity; instead a soft tissue mass with density of fat was found. This supports the theory that neurofibromatosis may have manifestations of a mesodermal dysplasia.

Unlabelled: Biopsy and histopathologic analysis may fail to consistently separate osteogenic sarcoma, osteomyelitis, and fibrous dysplasia., Objectives: To establish useful radiographic characteristics to differentiate these diseases, an objective preliminary study of radiographs of 30 cases of these diseases was done., Study Design: After precisely defining several radiographic characteristics and completing a calibration study, three observers unaware of the diagnosis examined study cases that were randomly ordered., Results: Despite using trained observers and strict criteria, differentiation of the three conditions is difficult on the basis of radiographic features alone. In osteogenic sarcoma, the distinguishing features were: permeative lesion borders, stippled bone pattern, destruction of cortical outlines, perpendicular spiculations of periosteal new bone, destruction of lamina dura, and widening of the entire periodontal ligament space. Presence of sequestra and laminations of periosteal new bone were the most useful distinguishing features in cases of osteomyelitis that otherwise resemble fibrous dysplasia. In fibrous dysplasia, superior displacement of the mandibular canal and a fingerprint bone pattern were pathognomonic. Displacement of the maxillary sinus cortex, alteration of lamina dura to the abnormal bone pattern, and narrowing of the periodontal ligament space were also useful distinguishing features., Conclusions: Our findings indicate that diagnosis cannot rely on radiographic characteristics alone, although some radiographic findings were more useful than others.

Apical root resorption is a serious iatrogenic problem sometimes associated with orthodontic treatment. The Speed appliance (Strite Industries, Ltd., Ontario, Canada) provides a continuous rotatory and torque action through its spring clip mechanism, in contrast with the edgewise appliance that may provide an interrupted force. The effect of continuous action on root resorption compared with the interrupted action of the edgewise system has not been investigated previously. The purpose of the present investigation is to test the null hypothesis that there is no difference in the apical root resorption seen after orthodontic treatment with the edgewise straight wire and the Speed appliance systems. Pretreatment and posttreatment periapical radiographs of 63 patients, (30 treated with the Speed 0.018 bracket and 33 with the 0.018 edgewise bracket) were studied. The long cone paralleling technique was used for all the radiographs. Any image distortion between the pretreatment and posttreatment radiograph was calculated and compensated for by using the crown length measurements, on the assumption that the crown length remains unaltered during the treatment period. Quantitative measurements of crown and root lengths for the maxillary and the mandibular central and lateral incisors were compared. Means and standard deviations for the percentage root resorption per tooth group were calculated. A three-factor analysis for variance (ANOVA test) was performed to determine whether there was an appliance, treatment, or gender effect on the amount of root resorption seen after treatment. No statistically significant difference in root resorption between the two appliance systems was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Odontogenic infections are frequently encountered by the dentist. The signs and symptoms of these common dental emergencies are outlined in this two-part article. A thorough knowledge of the fascial planes and anatomical routes of infection spread is a critical prerequisite to understanding the clinical manifestations, potential complications, and appropriate management of these infections.

New advances in imaging have added a significant amount of information, which has resulted in more accurate and detailed diagnosis of temporomandibular joint disorders. In the future, treatment methods may be devised that can use effectively this diagnostic information.

The incidence of internal derangement of the temporomandibular joint has been documented in patients with temporomandibular disorders. However, the detection and diagnosis of a displacement of the temporomandibular joint disc in relation to internal derangement is not always accurate, and it varies according to the method of examination. A prospective clinical investigation of 26 patients (45 temporomandibular joints) with signs and symptoms of temporomandibular joint pain and dysfunction was completed to examine the accuracy of clinical examination, sagittal recording device tracings, arthrography, and magnetic resonance imaging in detecting internal derangement in the temporomandibular joint. A group of 16 asymptomatic control subjects (32 temporomandibular joints) was examined for the presence of internal derangement by the methods under consideration. Incidence of bilateral internal derangement in the temporomandibular joints of the symptomatic patients was also assessed. Findings obtained through clinical examination and sagittal recording device tracings agreed most often with the arthrographic findings of internal derangement. Magnetic resonance imaging often failed to detect the presence of arthrographically detected internal derangement. Internal derangement was identified bilaterally in a significant number of patients, despite the absence of bilateral symptoms. This incidence varied according to the technique used. In the control group, 9% of the temporomandibular joints that had been assessed as normal according to clinical examination and sagittal recording device tracings were found to have internal derangement according to magnetic resonance imaging.

A variety of imaging modalities are available for the preoperative evaluation of potential implant sites. The pantomograph provides initial screening information. Cephalometric films are most useful in analyzing the incisor regions. Tomography can provide cross-sectional views of segments at a relatively low patient radiation dose. Computed tomography is a superior method when the analysis of complete arches is required. Experimental designs of postoperative radiologic evaluation of small changes in bone height require reproducible image geometry and the evaluation of intraobserver error.

The purpose of this study was to provide an objective analysis of the radiographic characteristics of histiocytosis X as it affects the jaws. The original radiographs of 29 cases were reviewed independently and objectively by three observers. The results suggest that seven characteristics, either alone or in combination, are useful in the identification of histiocytosis X. These include the appearance of solitary "intraosseous" lesions, the multiplicity of "alveolar bone" lesions, the "scooped-out" effect in the alveolar process, the well-defined periphery, sclerosis in the alveolar bone lesions, periosteal new bone formation, and slight root resorption.

A significant amount of radiation escapes the rear of an image receptor in conventional dental radiographic procedures despite the placement of a lead-containing backing at the rear of the film pack. The purpose of this investigation was to place additional layers of lead on the film pack in an attempt to reduce transmitted radiation to tissues behind the film. Reduction of dose to tissues behind the film causes a reduction in scatter radiation to critical organs such as the thyroid gland and salivary glands. A thermoluminescent lithium fluoride dosimetry system (TLD) was used and calibrated in both the beam of interest and tissue of interest. A tissue-equivalent anthropomorphic phantom was used for dose determination. Successive layers of lead foils were added to the image receptor, and dose was determined for each additional lead foil in the tissues behind the image receptor. Two sets of exposure conditions were used, namely: 70 kVp, 10 mA, and 0.6 s, and 90 kVp, 10 mA, and 0.6 s. The beam-film-patient orientation used was for a first molar bitewing radiographic projection. Four lead layers (three additional foils equalling 3.92 x 10(-3) mm of lead) on the conventional film package resulted in a significant dose reduction. Four layers of lead resulted in a dose less than one-third that of the conventionally shielded package.

A thermoluminescent dosimetry system was utilized to investigate how much the radiation dose is reduced through the addition of a niobium-based accessory filter to an X-ray unit's conventional aluminum filter. A two-bitewing series was exposed in a tissue-equivalent human phantom. The skin exposures from an X-ray beam with the added niobium filter and a beam with the aluminum filter alone were measured and compared. Thyroid dose distribution was also measured and similarly compared. Utilization of the niobium filter resulted in a significant reduction in skin exposure (p less than 0.001) of 14.8 per cent. Thyroid dose was not lessened by using the niobium filter, however. In fact, in one region of the thyroid it increased significantly.

The direct effect of 1,25(OH)2D3 upon osteoclast formation from precursor cells is still unknown. In the present experiments we have tested the effects of 1,25(OH)2D3 on the generation of osteoclastlike cells in cat bone marrow cultures. These cultures contain proliferating nonattached mononuclear cells and precursor cells that subsequently attach to the culture flask surface and then fuse to form multinucleated osteoclastlike cells. After 7 days of culture we separated the nonattached precursor cells from the attached cells and studied the effects of 1,25(OH)2D3 (10(-10) M - 10(-8) M) on multinucleated cell formation in these two cell populations. In cultures derived from the nonattached precursor cells, 7 days of treatment with 1,25(OH)2D3 (10(-8) M) resulted in a 180% increase in the number of attached mononuclear cells and a 90% increase in the number of nuclei contained within multinucleated cells. These effects were dose-dependent. 1,25(OH)2D3 did not have a consistent effect on the number of nonattached precursor cells. In cultures derived from attached cells, 7 days of treatment with 1,25(OH)2D3 (10(-8) M) induced a 50% increase in the number of mononuclear attached cells and a 40% increase in the number of nuclei within polykaryons. The most likely explanation for these results is that 1,25(OH)2D3 promotes the differentiation and subsequent adhesion of nonattached precursor cells, stimulates proliferation of attached mononuclear precursor cells, and possibly stimulates fusion of these attached precursor cells.

Our observations confirm the previously reported observation that multinucleated cells develop within a two-week period in cat bone-marrow cultures. Calcitonin induces cytoplasmic contraction in these multinucleated cells, which indicates that they resemble osteoclasts. After seven days of culture, cat bone-marrow cultures contain both non-attached mononuclear cells and attached mononuclear and polynuclear cells. We have cultured the attached and non-attached cell populations separately from day 7 onward and have observed the appearance of multinucleated cells in both culture systems. In both types of cultures, dexamethasone (10(-9)-10(-7) mol/L) reduced the number of multinucleated cells. This effect of dexamethasone was more rapid in the cultures derived from non-attached cells (seven days) than in cultures derived from attached cells (14 days), suggesting that two different mechanisms are involved. Dexamethasone had no effect on the survival of multinucleated cells already formed.

A radiographic technique was developed to accurately assess bone available for the placement of intraosseous implants. Hypocycloidal tomographs were made at right angles to the long axis of the mandibular and/or maxillary alveolus while the patient was wearing a specially designed splint. Alveolar height and width measurements were obtained from the resulting films. Sensitivity results for this technique showed that the mean difference between the actual bone height and width and that measured in the radiographs was 0.49 mm and 0.35 mm, respectively. A paired difference test revealed a range of 0.25 mm to 0.73 mm in the expected error in the height and 0.20 mm to 0.50 mm in width measurements with a 95 confidence interval.