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Biomedical subjects

M Rohlin

Publications and source records attributed to M Rohlin.

At least 73 records · Page 4Linked to original sources
PubMed1992

Measurements of tooth length in panoramic radiographs. 2: Observer performance.

Observer performance in tooth-length measurements in panoramic radiography has been examined. Sixty-four teeth, evenly distributed between maxillary first molars, second premolars and mandibular first and second premolars, were fixed in plastic moulds. Each cast was radiographed with an Orthopantomograph, twice with steel balls indicating the cusps and apices of the teeth and once without them. One observer measured the radiographic tooth length twice in both radiographs with indicators in order to estimate the true radiographic tooth length and the repositioning error, and twice in the radiographs without indicators. Seven other observers measured the tooth length on the radiographs without indicators, twice applying their own criteria and twice using defined criteria. The accuracy of the tooth-length measurements was calculated by comparing the true radiographic tooth length with the measurements of the seven observers. The intra-observer variation was defined as the difference between two measurements on the same radiograph. The accuracy and the precision of the tooth-length measurements were highly influenced by the observer performance. The mean radiographic tooth length of the seven observers was closer to the true radiographic tooth length when the observers applied the defined criteria. The inter- and intra-observer variation was higher for the measurements of the maxillary teeth (0.3-1.9 mm) compared with the mandibular teeth (0.3-0.9 mm) for most observers. The highest intra-observer variation was found for the palatal root of the maxillary first molar. The intra-observer variation of four observers decreased somewhat when the defined criteria were used; for the other three observers, however, the variation increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1992

Individualized periapical radiography determined by clinical and panoramic examination.

The efficiency of panoramic radiography compared with full-mouth periapical examination is an unresolved problem. The diagnostic yield of periapical lesions when the clinical signs and symptoms and the findings from a panoramic radiograph served as the basis for an individualized periapical radiographic examination was studied. Two hundred patients were examined clinically and radiographically. The periapical status was assessed step by step with access to increasing numbers of radiographs. For the clinical examination, the sensitivity was 0.24, the positive predictive value 0.62, the specificity 0.98, the negative predictive value 0.90 and the likelihood ratio for the positive test result 12. For radiographs indicated by the clinical examination plus the panoramic radiograph and selected periapical radiographs, both the sensitivity and the positive predictive value were 0.91, the specificity and the negative predictive value 0.99 each and the likelihood ratio was 91. False findings were twice as frequent in the upper as in the lower arch and particularly found in the incisor and premolar regions. In 30% of the patients no periapical radiograph was needed to supplement the panoramic radiograph. In the other patients, two supplementary periapical radiographs were needed on average. We conclude that the information obtained from the clinical and panoramic examinations supplemented with no more than two periapical radiographs will result in a high diagnostic yield on the periapical status.

False Negative Reactions↗
PubMed1992

Macroscopic and microscopic findings of areas with radiologic erosions in human temporomandibular joints.

The aim was to describe the macroscopic and microscopic findings of areas with radiologic erosions in the human temporomandibular joint. An autopsy material of 40 human joints, removed as blocks, was examined with tomography, and an erosion was found in 37 areas. A macroscopic and a microscopic examination focused on the presence of the calcified cartilage zone (CCZ) was performed in these areas. In the condyle 13 of 14 areas with a radiologic erosion showed denudation of bone macroscopically. Microscopically, these areas were covered by a thin fibrocellular tissue, and the CCZ was absent. In the temporal component, only 1 of the 23 areas showed bone exposure macroscopically. Microscopically, the soft tissue in these areas varied in thickness. The CCZ was missing in 13 of the 23 areas, even in some areas that appeared normal macroscopically and were microscopically covered by intact soft tissue. Thus, in areas with a radiologic erosion the macroscopic and microscopic appearance differed between the condyle and the temporal component. The nature of the findings is discussed.

Aged↗
PubMed1992

Subtraction radiography of interradicular bone lesions.

Subtraction and conventional radiography were evaluated for their diagnostic potential to assess interradicular bone lesions in the mandibular premolar region. Both conventional radiographs and subtraction images were interpreted by 10 observers. The receiver-operating characteristic (ROC) technique was used to compare the two techniques. The diagnostic validity was higher for the subtraction technique, both for lesions confined to cancellous bone and for lesions including the cortical bone, than for the conventional technique. For bone defects confined to cancellous bone the diagnostic accuracy was lower than those reported from periapical bone lesions irrespective of whether subtraction or conventional radiography was used. We conclude that subtraction radiography improves the detectability of bone lesions, shallow ones in particular. Lesions in the interradicular bone are more difficult to detect than those in the periapical bone.

Alveolar Process↗
PubMed1992

Comparative means of dose reduction in dental radiography.

This review on dose reduction in dental radiography focuses on criteria for selecting the frequency and type of radiographs to be performed on patients. By making radiographs only when there is a reasonable probability of a finding that will influence patient care, patient exposure and other radiographic costs may be substantially reduced. Patient dose may also be reduced by half by changing from D-speed film to E-speed film for intraoral radiography and by more than half by changing from calcium tungstate intensifying screens to rare-earth intensifying screens for panoramic and cephalometric radiography. Using rectangular collimation for intraoral radiography will also further reduce patient exposure by about fourfold. Finally, the use of time-temperature processing will prevent overexposure of the patient and underprocessing of the radiographs; optimal radiographs will be provided.

Humans↗
PubMed1991

Radiologic changes in temporomandibular, hand, and foot joints of patients with rheumatoid arthritis.

Radiologic changes in the temporomandibular joint (TMJ) and in the joints of the hand and foot were recorded for 90 adult patients with rheumatoid arthritis. The severity of the changes was graded according to the Larsen classification of six grades (O to V), and mainly erosive changes were recorded. The assessment of the radiographs was performed with the aid of reference films. The radiologic changes in the TMJs corresponded to grade II (definite early abnormality) and paralleled those of most of the metacarpophalangeal and metatarsophalangeal joints. The most severe changes were localized to the wrists, with a median grade of III (moderate destructive abnormality). The severity of the changes was similar on the right and left sides of the TMJ. We conclude that TMJ involvement in patients with rheumatoid arthritis is severe and warrants a thorough initial clinical examination. Such a strategy will facilitate the diagnosis and treatment of TMJ changes in the early stages of the disease.

Adolescent↗
PubMed1991

Observer performance in the assessment of periapical pathology: a comparison of panoramic with periapical radiography.

Observer performance in the assessment of the periapical pathology from panoramic and periapical radiography was examined. Five endodontists, five general practitioners and five oral radiologists were asked to assess the periapical status of 117 teeth. The observers assessed the panoramic and periapical radiographs of the teeth, which were evenly distributed throughout the jaws with a 50% probability that either an osteolytic or sclerotic lesion was present. The results of the comparison between panoramic and periapical radiography were influenced by the selection of observers. When the oral radiologists acted as observers, the mean P(A) value for periapical radiography was higher than for panoramic radiography (P less than 0.001), resulting in periapical radiography presenting a higher overall diagnostic accuracy than panoramic radiography for all 15 observers (P less than 0.01). There was, however, no difference between panoramic and periapical radiography when the two groups of endodontists and general practitioners acted as observers. The comparison of the three groups of observers showed no difference between their diagnostic accuracy when assessing panoramic radiographs. With periapical radiography, the oral radiologists demonstrated a higher diagnostic accuracy than the endodontists (P less than 0.05). The observers in each group with the highest diagnostic accuracy also had the highest intra-observer agreement. The mean intra-observer agreement of the five general practitioners was higher than those of the other two groups of observers for panoramic radiography. For periapical radiography, the mean agreement rates of the groups were comparable.

Adult↗
PubMed1990

Clinical and radiological findings in temporomandibular joints with disc perforation.

Sixteen temporomandibular joints from 15 patients, reported to have disc perforation at arthrography, were studied. Pain from the TMJ region was reported by 11 patients. Clicking was found in 6 joints and crepitation in 6 joints. Nine patients displayed a deviation of the mandible at maximum mouth opening towards the affected side. The muscles of the affected side were tender on palpation more frequently than those on the contralateral side. The disc perforation was located in the posterior attachment in most joints. An anterior disc displacement was found in all joints except one, which exhibited a normal disc position. In 4 joints with an anterior disc displacement with reduction, the configuration of the discs varied, whereas in all 11 joints with an anterior disc displacement without reduction the disc was biconvex. In most joints, the condyle was located in a central position in the fossa in the intercuspal position and 13 joints were tomographically diagnosed as being osteoarthrotic. It is concluded that most joints with disc perforations are osteoarthrotic and the most severe clinical and radiological findings are associated with an anterior disc displacement without reduction.

Adult↗
PubMed1990

Diagnostic outcome and observer performance in sagittal tomography of the temporomandibular joint.

The diagnostic outcome and observer performance of sagittal tomography in detecting degenerative lesions of the temporomandibular joint was studied. Thirty tomograms depicting findings such as cyst, erosion, osteophyte and sclerosis and 30 with a normal appearance were selected. The joint status was verified histologically. Four observers evaluated the tomograms with the aid of reference tomograms, independent of the microscopic examination. The diagnostic accuracy was high (80-87%). The sensitivity was between 67% and 90% and the specificity between 73% and 93%. An osteophyte was, with few exceptions, a true finding whereas sclerosis most frequently was false. About two-thirds of the reports of cyst and erosion were found to be true. The interobserver overall agreement rates for any two observers varied between 68% and 90%, for three observers between 65% and 82%, and for all four observers was 63%. The Kappa value for any two observers was 0.40-0.80, indicating fair to substantial agreement. The intra-observer agreement was only somewhat higher than the interobserver. This study shows that, with the aid of reference tomograms, high diagnostic accuracy and observer agreement can be achieved in sagittal tomography.

Aged↗
PubMed1990

Comparison of computed with conventional tomography in the evaluation of temporomandibular joint disease: a study of autopsy specimens.

Autopsy specimens were examined both radiographically and macroscopically to compare direct computed tomography (CT) with conventional tomography (CVT) for their diagnostic yield of the structural bone changes in the temporomandibular joint (TMJ). Fifteen specimens were examined with corrected sagittal and 12 with corrected frontal tomography. Five joints showed bone exposure and/or disc perforation macroscopically and all of them were correctly diagnosed by both CT and CVT (sensitivity 1.0). However, false-positive diagnoses were also made, resulting in values for specificity which were somewhat lower for CT than for CVT. Frontal images did not reveal any additional 'true' findings compared with sagittal CT or CVT. For single areas of the joints the average sensitivity was low, 0.28 for CT and 0.47 for CVT, but the specificity for the joint as a whole was high with both methods (0.91 and 0.94 respectively). We conclude that CVT is superior to CT in the diagnosis of single structural bone changes but comparable for comprehensive diagnosis of TMJ disease.

Adult↗
PubMed1989

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.

Arthritis, Rheumatoid↗
PubMed1989

Comparison between panoramic and posterior bitewing radiography in the diagnosis of periodontal bone loss.

A study is reported comparing the diagnostic yield of panoramic and posterior bitewing radiographs when used to image periodontal bone disease. It is concluded that there is a high concordance between the findings from the two types of radiographs but that the concordance varies with the degree of bone loss and tooth type. Consequently when panoramic radiography is used in clinical practice, the examination should be supplemented by intraoral radiographs in regions when image quality is poor in the panoramic image and where there are structures of special interest.

Adult↗