Arne Petersson

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.

What you can and cannot see in TMJ imaging--an overview related to the RDC/TMD diagnostic system.

In the current version (I) of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), imaging of the temporomandibular joint (TMJ) is not required for a diagnosis. Research has shown that radiological findings of the TMJ do not always support the clinical findings of the RDC/TMD diagnosis. But imaging should only be performed when it is known that it could contribute to (i) a proper diagnosis and (ii) treatment with a better prognosis. Several techniques are used to image the TMJ: panoramic radiography, plain radiography, conventional and computed tomography (CT), digital volume tomography or cone-beam computed tomography (CBCT), arthrography and magnetic resonance imaging (MRI). Osseous changes are best visualized in tomography, and the newly developed CBCT is a promising method but must be evaluated in a comparative analysis with other tomographic techniques. And although MRI is the method of choice for imaging the disc, a systematic review found the evidence grade for the diagnostic efficacy of MRI to be insufficient. Today, there is no clear evidence for when TMD patients should be examined with imaging methods. Future research designs should be randomized controlled trials where various radiological examination findings are analysed in relation to therapeutic outcome. In future versions of the RDC/TMD diagnostic system, recommended radiographic techniques must be evaluated and defined, diagnostic criteria well defined and observers calibrated.

Assessment of the trabecular pattern before endosseous implant treatment: Diagnostic outcome of periapical radiography in the mandible

OBJECTIVES To study the diagnostic outcome of periapical radiography in the assessment of the bone trabecular pattern of the mandible. STUDY DESIGN Mandibular autopsy specimens were radiographed. Seven observers assessed the radiographs with the aid of a proposed classification with and without reference images and the classification presented by Lekholm and Zarb. Accuracy was estimated on the basis of morphometric measurements of trabecular bone volume. Observer agreement was calculated as the estimated probability of agreement between and within observers and as kappa index. RESULTS With the classification proposed by us, the overall accuracy was 58% with and 50% without reference images. The accuracy for assessing dense trabeculation was higher (78%) than that for sparse trabeculation (28%). The accuracy of the proposed classification by Lekholm and Zarb was not possible to evaluate. The interobserver agreement varied between 49% and 64% and the intraobserver agreement between 75% and 86%. CONCLUSION A new classification with reference images is recommended to assess the trabecular pattern in periapical radiographs before implant treatment.

Diagnosis of the condition of the dental pulp: a systematic review.

The aim of this systematic review was to appraise the diagnostic accuracy of signs/symptoms and tests used to determine the condition of the pulp in teeth affected by deep caries, trauma or other types of injury. Radiographic methods were not included. The electronic literature search included the databases PubMed, EMBASE, The Cochrane Central Register of Controlled Trials and Cochrane Reviews from January 1950 to June 2011. The complete search strategy is given in an Appendix S1 (available online as Supporting Information). In addition, hand searches were made. Two reviewers independently assessed abstracts and full-text articles. An article was read in full text if at least one of the two reviewers considered an abstract to be potentially relevant. Altogether, 155 articles were read in full text. Of these, 18 studies fulfilled pre-specified inclusion criteria. The quality of included articles was assessed using the QUADAS tool. Based on studies of high or moderate quality, the quality of evidence of each diagnostic method/test was rated in four levels according to GRADE. No study reached high quality; two were of moderate quality. The overall evidence was insufficient to assess the value of toothache or abnormal reaction to heat/cold stimulation for determining the pulp condition. The same applies to methods for establishing pulp status, including electric or thermal pulp testing, or methods for measuring pulpal blood circulation. In general, there are major shortcomings in the design, conduct and reporting of studies in this domain of dental research.

Sagittal Splitting of the Mandibular Ramus: Electromyography and Radiologic Follow-up Study of Temporomandibular Joint Function in 44 Patients

A follow-up study was performed on 44 patients operated with sagittal splitting of the mandibular ramus for correction of a mandibular protrusion. The study included clinical examination, electromyography and masticatory efficiency test as well as radiography of the temporomandibular joint. The maximum opening capacity and protrusion of the mandible decreased one to three years after the operation. The activity of the temporal muscle decreased in rest position after the operation. Masticatory efficiency was unchanged. The position of the condyle in the fossa was unchanged postoperatively, while a posterior and superior condylar movement occurred during the fixation period. Normalization of the condylar position tended to occur one year after the operation. In 37 of 86 condyles, a double contour was seen on the postesuperior margin of the condyle one year after the operation. Possible mechanism behind the development of the new condylar bone layer is discussed.

Relationship between clinical and radiologic findings of the temporomandibular joint in rheumatoid arthritis.

The relationship between clinical findings in the craniomandibular system and radiologic findings in the temporomandibular joint was investigated in 101 adults with rheumatoid arthritis. Radiologic changes were correlated with duration and severity of temporomandibular joint symptoms and general joint disease. The radiologic changes were also associated with loss of occlusal support, anterior open bite, and occlusal interferences. Most joints with crepitus exhibited radiologic erosion. Joints with mutilating changes were silent.

Rheumatoid arthritis of the temporomandibular joint: Radiologic evaluation based on standard reference films

A radiologic scoring system that uses tomography and panoramic radiography to evaluate severity of rheumatoid arthritis in the temporomandibular joint of adults is presented. The scoring system is based on six verbally described grades illustrated by standard reference films. The interobserver agreement was significantly higher for the grading with reference films than for that without reference films. Intraobserver performance was similar for grading with and without reference films. The grading system with reference films is recommended in epidemiologic studies of rheumatoid arthritis localized to the temporomandibular joint or other studies in which multiple observers are involved.

Effect of ambient light and monitor brightness and contrast settings on the detection of approximal caries in digital radiographs: an in vitro study

OBJECTIVES The aim of this study was to investigate how brightness and contrast settings of the display monitor and ambient light level (illuminance) in the viewing room affect the clinicians ability to diagnose carious lesions in digital radiographs. METHODS Standardized radiographs were taken of 100 extracted teeth. Seven observers evaluated the images for approximal carious lesions twice, once under 50 lux and once under 1000 lux room illumination. Monitor brightness and contrast were varied +/-50% and +/-6%, respectively, to mimic the normal limits of monitor adjustment by an inexperienced user and one optimal setting. This was done by adjusting radiograph brightness and contrast by +/-25%. Thus, five radiographs of each tooth were evaluated. Receiver operating characteristic (ROC) analyses were performed. Histological examinations of the teeth served as the criterion standard. A paired t-test was used to evaluate whether differences in the areas under the ROC curves were significant and kappa was used to evaluate intraobserver agreement. RESULTS When a monitor with optimal brightness and contrast settings was used to detect approximal carious lesions, ambient light levels less than 50 lux were significantly better than levels above 1000 lux (dentin and enamel lesions, P < 0.01; dentin lesions, P < 0.02). Increasing the contrast setting of the monitor by 6% did not change these results; 50 lux was still significantly better than 1000 lux (enamel lesions, P < 0.01; dentin and enamel lesions, P < 0.02) for evaluating radiographs. Intraobserver agreement differed from fair to good. CONCLUSIONS Reducing ambient light to less than 50 lux significantly increased the accuracy of diagnosing approximal carious lesions on a monitor with an optimal brightness setting and an optimal or slightly higher than optimal contrast setting.

Maxillary bone mineral density and its relationship to the bone mineral density of the lumbar spine and hip

OBJECTIVE We sought to measure the bone mineral density (BMD) of various regions in the maxilla before implant treatment and to investigate correlations between these values and the BMDs of the spine and hip. STUDY DESIGN Eighteen patients were examined by means of quantitative computed tomography, and the BMD of the maxillary alveolar ridge was calculated. The same patients also underwent dual-energy x-ray absorptiometry of the lumbar spine and the total hip. Analysis of variance was used to compare BMD values between and within individuals. The Pearson correlation coefficient was used to correct for sex and body mass and to calculate the correlation between the BMD of the maxillary alveolar ridge and the BMD of the spine and hip. RESULTS The maxillary BMD varied significantly between individuals (P <.001) and within individuals (P <.001). The BMD of the anterior region of the maxilla was correlated significantly with the BMD of the lumbar spine (r=0.6; P <.05). CONCLUSION A site-specific evaluation of maxillary bone tissue could be of value before implant treatment.

Narrowing of the dental pulp chamber in patients with renal diseases

Narrowing of the dental pulp chamber was studied radiologically in fifty one patients with renal diseases. Two thirds of the patients were suffering from terminal uremia and were treated either by renal transplantation or with hemodialysis. The remaining patients were nonuremic and were treated with immunosuppressants because of progressive renal disease. There were significantly more patients with narrowing of the dental pulp chamber among the transplant patients than among the other patients. The transplantations included the use of higher doses of corticosteroids than the other treatments. As the median dose of corticosteroids was higher and total plasma steroid clearance was lower in the patients with narrowing of the dental pulp chamber than in the other patients, the amount of this drug received and its pharmacokinetics seemed to be an essential factor in the initiation of narrowing of the dental pulp chamber.