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Biomedical subjects

A Petersson

Publications and source records attributed to A Petersson.

At least 55 records · Page 3Linked to original sources
PubMed1993

Assessment of a new processor containing a self-cleaning synthetic-web transport mechanism.

The effect of two different types of automatic X-ray processing machines (a roller-based Pantomat P10 and the Velopex which has a novel web transport system) on the accuracy of radiographic diagnosis of caries in extracted premolars was evaluated. Seven observers graded the occurrence of caries and their findings were compared with actual prevalence of the disease. The accuracy was measured with the ROC technique. Kodak Ektaspeed dental X-ray film was used. The results showed no significant differences in diagnostic accuracy between the two developing machines. The Velopex gave a check pattern to the films, but it was not so marked as to have a major influence on diagnostic accuracy.

Analysis of Variance↗
PubMed1993

A comparison of Flow and Kodak dental X-ray films by means of perceptibility curves.

Flow D- and E-speed group dental X-ray films (DX-58 and EX-58) have recently been introduced to the market. By means of perceptibility curves these films were compared with commonly used dental X-ray films (Kodak Ultraspeed and Ektaspeed). No major differences between the films were found with regard to contrast and the subjectively assessed number of small contrast differences. The exposure for EX-58 had to be lowered by 66% and Ektaspeed by 39% compared with Ultraspeed film to obtain the same density. DX-58 and Ultraspeed were of the same sensitivity.

Analysis of Variance↗
PubMed1993

Clinical follow-up with different disc positions.

A clinical follow-up of 45 previously symptomatic patients with arthrographically diagnosed TMJ disc positions was performed at least 1 year (average, 4 years 4 months) after treatment. The patients were divided into three groups according to disc position: (1) superior disc position, n = 5; (2) anterior disc displacement with reduction, n = 17; and (3) anterior disc displacement without reduction, n = 23. Ninety-two percent of the patient were treated conservatively. Seventy percent of the patients reported being symptom-free or improved. The frequency of joint clicking did not change considerably, but the amount of crepitating sounds increased markedly. No difference was found regarding treatment outcome between the anterior disc displacement groups with and without reduction.

Adolescent↗
PubMed1992

Visualisation of the mandibular canal by different radiographic techniques.

6 mandibles were radiographically examined bilaterally to visualise the mandibular canal. 5 imaging techniques were used: periapical radiography, panoramic radiography, hypocycloidal tomography, spiral tomography and computed tomography (CT). Panoramic radiographs were obtained with 2 different X-ray machines. The CT-examinations comprised direct images and standard reconstructions based on axial slices. The specimens were subsequently sectioned for contact radiography. The visibility of the mandibular canal was estimated by 3 observers at special reference points on all radiographs and classified as clearly visible, questionable visibility or not visible. The contact radiographs served as the "gold standard". The inter-observer and the intra-observer agreement were assessed by calculating the overall agreement and the x value. Direct coronal computed tomography, as well as spiral and hypocycloidal tomography, gave better visualisation of the mandibular canal than periapical and panoramic radiography.

Cadaver↗
PubMed1992

Estimation of the possibility to treat the edentulous maxilla with osseointegrated implants.

The possibility to treat individuals with an edentulous maxilla with osseointegrated implants was studied in randomly selected individuals from the city of Malmö. From a panoramic radiograph one oral radiologist and one oral surgeon together decided possible number and length of implants potentially installable. It was found that treatment with osseointegrated implants could possibly be done in 80% of the individuals and in 20% bone transplantation would have been necessary. Preoperative tomography was needed in about two thirds of the individuals for a more accurate evaluation of the degree of bone resorption.

Adult↗
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

Isolation and partial characterization of immunoglobulin from cod (Gadus morhua L.).

Serum immunoglobulins (CS-Ig) from cod (Gadus morhua L.) were prepared by precipitation with ammonium sulphate and molecular sieving. The molecular weight estimated from molecular sieving and electrophoresis was 851 kD for the whole molecule and 81 and 27.5 kD for the two subunits. This suggests a tetrameric structure of the molecule. The isoelectric point of CS-Ig was determined to approximately pH 5.0. The amino acid composition and absorbancy at 280 nm are very similar to published data of IgM from other fish species as well as from several mammals. CS-Ig has a natural binding capacity to a number of antigens used for immunization. Assays of antibody activity of fractionated cod serum indicates that CS-Ig does not exist as a monomeric molecule. As the characteristics of CS-Ig are very similar to those found in other fish species, we believe that CS-Ig is an IgM-like molecule.

Amino Acids↗
PubMed1991

Some anatomical factors of the upper compartment of the temporomandibular joint related to the disc position.

Temporomandibular joint (TMJ) arthrograms of 20 joints with superior disc position (SDP), 20 joints with anterior disc displacement with reduction (ADDWR), and 20 joints with anterior disc displacement without reduction (ADDWOR) were compared. The distance from the insertion of the posterior disc attachment of the upper joint compartment to the top of the mandibular fossa in joints with ADDWR was significantly longer than in joints with SDP and ADDWOR (p = 0.003). The distance from the top of the mandibular fossa to the top of the articular eminence in joints with ADDWR was significantly shorter than in joints with ADDWOR (p = 0.006). The entire distance of the upper joint compartment in joints with ADDWR was significantly longer than in joints with SDP and ADDWOR (p = 0.02).

Adult↗
PubMed1991

Angulation and prominence of the posterior slope of the eminence of the temporomandibular joint in relation to disc position.

A steep articular eminence has been proposed as an aetiological factor in internal derangement of the temporomandibular joint. Arthrograms of 20 joints each of three groups, superior disc position (SDP), anterior disc displacement with reduction (ADDWR) and anterior disc displacement without reduction (ADDWOR) were compared. No correlation was found between a steep articular eminence and anterior disc displacement. The posterior slope of the articular eminence of the joints with ADDWOR was significantly less prominent than in those with SDP and ADDWR.

Adolescent↗
PubMed1991

Influence of tube voltage on radiographic diagnosis of caries in premolars and molars.

The influence of tube voltage on radiographic diagnosis of caries in extracted premolars and molars was examined. Five combinations of dental X-ray machines and kV-settings were used (Philips Oralix 65 kV; Siemens Heliodent EC 60 kV; Siemens Heliodent 70 kV; Soredex Minray DC 60 kV and 70 kV). The diagnostic accuracy was evaluated with the ROC-technique. The results showed no significant differences in the diagnostic accuracy between premolars and molars. However, the diagnostic accuracy tended to be better with low kilovoltage for radiography of premolars and high kilovoltage for radiography of molars.

Bicuspid↗
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

Long-term effects of the Herbst appliance on the craniomandibular system with special reference to the TMJ.

The purpose of this study was: (1) to analyse the long-term clinical implications of Herbst treatment on the masticatory system, and (2) to analyse the radiographic appearance of the temporomandibular joints at the time of follow-up using lateral tomography of the right and left TMJ. The sample consisted of 19 consecutive male subjects with a Class II, Division 1 malocclusion treated with the Herbst appliance for an average period of 7 months. The patients were reinvestigated at the end of the growth period (an average of 7.5 years after treatment). The anamnestic, clinical, and radiographic findings revealed that Herbst treatment did not seem to have any long-term adverse effects on the craniomandibular system.

Activator Appliances↗
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↗
PubMed1990

Influence of different developing solutions and developing times on radiographic caries diagnosis.

One hundred extracted premolars were radiographed under standardized conditions with D- and E-speed films. The films were developed with conventional and rapid processors using varying developing times. The influence of different developers and developing times on the diagnostic accuracy of radiographic caries diagnosis was evaluated with the aid of ROC technique. Rapid processing using the developing time recommended by the manufacturer led to a lower density and contrast compared with the conventional developer. Underdeveloped films using the rapid processors resulted in an unacceptable low level of diagnostic accuracy, but otherwise it was the same for all developers, developing times and both types of film.

Bicuspid↗
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↗