Lars Hollender

Imaging of the temporomandibular joint: a position paper of the American Academy of Oral and Maxillofacial Radiology.

Various imaging techniques for the temporomandibular joint are discussed with respect to uses, strengths, and limitations. An imaging protocol is outlined for evaluating patients with a wide variety of temporomandibular joint related signs and symptoms.

Relationship of mandibular condylar position to dental occlusion factors in an asymptomatic population.

This article investigates the influence of occlusion on condylar position as seen on TMJ tomograms in a group of 44 young adults with no histories of orthodontic or occlusal therapy and no objective signs of masticatory dysfunction; the sample was screened from a population of 253 students. Nonconcentric condylar position at ICP was a feature of Class II malocclusion with significantly more anterior positions in Class II, Division 1 than in Class I. Condylar position was unrelated to the amount of sagittal RCP-ICP slide, although most slides were less than 0.5 mm. The frequency of lateral slides was low, but was mildly related to bilaterally asymmetric condylar positions. Position was unrelated to the degree of overbite, which ranged from 0 to 10 mm. Bilateral condylar position asymmetry was not related to the direction of dental midline discrepancy, which ranged from 0 to 2 mm. No open bites or mandibular overjets were seen in this asymptomatic normal sample.

Variation in condyle-fossa relationships according to different methods of evaluation in tomograms

Mandibular orthopedic diagnosis is frequently based on observation of radiographic nonconcentric condyle-fossa relationships, but the definition of normal and abnormal positions is, in part, obscured by the several different methods used to assess condyle position and the absence of intermethod comparisons. This study compared the measurement and expression of condyle position in tomograms according to subjective evaluations and linear and area measurement of the interarticular space by use of a microcomputer and graphics tablet. Area analysis showed the least concordance with the subjective evaluation. Linear measurement of the subjective closest anterior and posterior interarticular space presented the greatest concordance, had low interobserver variation, and was considered clinically relevant to the functional thickness of the center of the articular disk.

Comparison of clinical and magnetic resonance imaging diagnoses in patients with disk displacement in the temporomandibular joint

OBJECTIVE The purpose of this study was to validate the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) for the diagnostic subgroup of disk displacement with reduction, with magnetic resonance imaging used as a gold standard. STUDY DESIGN The diagnoses from the clinical examination of 78 joints in 39 patients, each with disk displacement with reduction in at least one TMJ, were compared with magnetic resonance imaging diagnoses. The readers of the magnetic resonance images were blinded to the clinical diagnoses. The data analysis included kappa statistics and calculation of predictive values. RESULTS The predictive value of the RDC/TMD for disk displacement with reduction was 0.65. For disk displacement alone-the movement of the disk on opening not being considered-the predictive value was 0.92. The diagnostic agreement between RDC/TMD and magnetic resonance imaging diagnoses for all joints examined was 53.8%. Most of the disagreement was due to false negative clinical diagnoses for asymptomatic joints. CONCLUSIONS A positive RDC/TMD examination is predictive for internal derangement but not reliable with regard to the type of disk displacement; such examination is therefore of limited value in determining the true disk position and its functional movements.

Radiovisiography versus conventional radiography for detection of small instruments in endodontic length determination. Part 1. In vitro evaluation

Radiovisiography is a new intraoral radiographic imaging system. In this in vitro investigation, radiovisiography was compared with conventional radiographs viewed with x2 magnification. Twenty-five extracted maxillary molars were evaluated for clarity of size 8 and 10 endodontic file tips in relation to the radiographic apex. Five images of radiovisiography were compared with D-speed and E-speed radiographs: original, enhanced, negative-to-positive, standard zoom, and zoom in the negative-to-positive mode. D-speed radiographs were also compared with E-speed radiographs. Zoom in the negative-to-positive mode was statistically equivalent to D-speed radiographs (p = 0.264) and superior to E-speed radiographs (p < 0.001). The standard zoom was also superior to E-speed radiographs (p = 0.025). D-speed radiographs were statistically superior to E-speed radiographs; being judged better than E-speed 90% of the time. Accurate identification of the position of the tips of size 8 and 10 files was achieved on all D- and E-speed radiographs with the use of magnification.

Relationship between orthodontic treatment, condylar position, and internal derangement in the temporomandibular joint

The purpose of this study was to test the hypothesis that retraction of maxillary front teeth may lock the mandible in a posterior position, and to evaluate any relationship between condylar position and signs and symptoms of internal derangements in the temporomandibular joint. A total of 29 female patients treated for Angle Class II, Division 1 malocclusion with extraction of maxillary first premolars and 34 female patients treated for Angle Class I malocclusion without tooth extraction consented to participate in a radiographic and clinical follow-up examination. The mean ages of the patients were 16.9 (SD 3.0) and 16.6 (SD 2.6) years, and the mean times after treatment were 1.6 (SD 1.0) and 1.5 (SD 0.9) years, respectively. Condylar position was measured in percent anterior and posterior displacement from absolute concentricity on lateral, central, and medial tomographic sections of each joint. Mean condylar position was more posterior at right central (P < 0.05) and medial (P < 0.01) tomographic sections in patients treated with extraction. The difference was due to a higher frequency of anteriorly positioned condyles in the nonextraction cases. No intergroup differences in the sagittal occlusal slide from CR to CO and the number of patients with clicking were found. However, the condyles were located more posteriorly in all tomographic sections (P < 0.05 for lateral, P < 0.001 for central and medial) in patients with clicking than in those without.The purpose of this study was to test the hypothesis that retraction of maxillary front teeth may lock the mandible in a posterior position, and to evaluate any relationship between condylar position and signs and symptoms of internal derangements in the temporomandibular joint. A total of 29 female patients treated for Angle Class II, Division 1 malocclusion with extraction of maxillary first premolars and 34 female patients treated for Angle Class I malocclusion without tooth extraction consented to participate in a radiographic and clinical follow-up examination. The mean ages of the patients were 16.9 (SD 3.0) and 16.6 (SD 2.6) years, and the mean times after treatment were 1.6 (SD 1.0) and 1.5 (SD 0.9) years, respectively. Condylar position was measured in percent anterior and posterior displacement from absolute concentricity on lateral, central, and medial tomographic sections of each joint. Mean condylar position was more posterior at right central (P less than 0.05) and medial (P less than 0.01) tomographic sections in patients treated with extraction. The difference was due to a higher frequency of anteriorly positioned condyles in the nonextraction cases. No intergroup differences in the sagittal occlusal slide from CR to CO and the number of patients with clicking were found. However, the condyles were located more posteriorly in all tomographic sections (P less than 0.05 for lateral, P less than 0.001 for central and medial) in patients with clicking than in those without.

Assessment of mandibular condyle position: A comparison of transcranial radiographs and linear tomograms

Transcranial radiographs are frequently used to assess condyle-fossa relationships. However, their validity in representing condyle position has been questioned. Intermethod comparisons were performed between methods assessing condyle position by subjective evaluation and by linear and area measurement of the interarticular space. Linear measurement of the subjective closest anterior and posterior interarticular space and subjective evaluation were the mutually preferred methods in both transcranial radiographs and tomograms. Statistically significant correlations were shown (p less than 0.05) for condyle position between pairs of clinical transcranial radiographs and linear tomograms of the same temporomandibular joints. However there was a qualitative concordance in assessed posterior concentric and anterior positions in only 80% of the pairs, and a full concordance in the degree of condylar displacement was found in only 60% of the cases. Although still clinically helpful, the use of transcranial radiographs to monitor small changes in condylar position relative to the tomogram was questioned.

Number of teeth and residual alveolar ridge height in subjects with a history of self-reported osteoporotic fractures.

The purpose of this case-control study was to determine if elderly subjects with a history of osteoporotic fractures have fewer teeth and greater residual ridge resorption than subjects without such fractures. Patients older than 60 with a panoramic radiograph were invited to a phone interview. Information was obtained regarding fracture history, smoking, and hormone replacement therapy (HRT). The number of teeth was obtained from the panoramic radiograph. The residual ridge height of the edentulous mandible was measured at the site of the mental foramen. Multiple regression models were used to assess the association between fracture status and number of teeth or residual ridge height (controlling for age, gender, HRT, smoking, height and weight). Cases (n=93) were individuals reporting osteoporotic fractures (fractures occurring after minor impact). Controls (n=394) were individuals reporting traumatic fractures (n=105) or no fractures (n=289). Fracture status in this population affect neither the number of teeth nor the residual ridge height. In the regression model, the variables that had a statistically-significant effect on the number of teeth were age (p<0.0001) and smoking (p<0.0001). There was a dose-effect of smoking on the number of teeth. In the regression model, the variables that had a significantly-significant on residual ridge height (n=95 edentulous subjects) were age and gender. Our conclusion was that in elderly dental-school patients the number of teeth and residual ridge height were not influenced by fracture status. Age and smoking had the most influence ; there was no effect from HRT. The clinical implication is that a history of osteoporotic fractures is not an important cause for tooth loss and residual ridge resorption in an elderly dental-school population.

Clinical Science Comparison of Xeroradiographs and Film for Detection of Periapical Lesions

Xeroradiographs and Kodak Ektaspeed film were compared with Kodak Ultraspeed film for their ability to reveal periapical lesions. Cadaver specimens containing teeth which were normal or demonstrated periapical inflammatory disease were used as the test objects. These specimens were first radiographed using xeroradiographic plates or film. Following radiography, histologic analysis revealed the true presence or absence of disease. Ten oral radiologists scored all xeroradiographic and film images of the specimens for the presence of periapical disease. In general, the observers detected about 70% of the cases with periapical disease, while simultaneously considering about 10 to 15% of the normal surfaces to be abnormal. Receiver-operating-characteristic (ROC) analysis of the radiographic decisions revealed little difference in the diagnostic performance of the observers using the various image receptors, although both types of film and low-contrast xeroradiographs viewed in transmitted light were all more useful than low-contrast xeroradiographs viewed in reflected light. In terms of patient dose, both xeroradiographic images and Ektaspeed film are preferred over Ultraspeed film.

Fractal dimension evaluation of cone beam computed tomography in patients with bisphosphonate-associated osteonecrosis

OBJECTIVES The aim of this study was to (1) evaluate the fractal dimension (FD) in regions of the mandible on cone beam CT (CBCT) images of patients with bisphosphonate-associated osteonecrosis of the jaws (BP-ONJ) and (2) to select the most suitable region of interest (ROI) for further study on detection of bone alterations associated with bisphosphonates. METHODS CBCT images of patients with BP-ONJ were included with matched controls. Values of FD were compared between groups. Selected ROIs were: ROI-1 - below the mandibular foramen; ROI-2 - above the mandibular foramen; ROI-3 - anterior to the mental foramen; ROI-4 - above the mandibular canal. The area of bone exposure was included as ROI-5. The results were analysed using generalized estimating equations and conditional logistic regression. RESULTS There were 36 patients (67% female) with a mean age of 60.7 years. The mean FDs were: ROI-1 - 1.678 for controls and 1.673 for patients (P = 0.81); ROI-2 - 1.657 for controls and 1.653 for patients (P = 0.78); ROI-3 - 1.661 for controls and 1.684 for patients (P = 0.17); and ROI-4 - 1.670 for controls and 1.698 for patients (P = 0.03). The value of the FD in the area of exposed bone was the highest (1.729). The odds of being a BP-ONJ patient vs being a control was six times as high for individuals with a higher FD score at ROI-4, although the confidence interval was quite wide owing to the small sample size. CONCLUSION In this preliminary study, BP-ONJ patients had higher FD values than controls at regions close to the alveolar process. The results suggest that FD is a promising tool for detection of bone alterations associated with BP-ONJ.