Search PubMed⌕ Search

Biomedical subjects

A Petersson

Publications and source records attributed to A Petersson.

At least 91 records · Page 5Linked to original sources
PubMed1987

Is E-speed dental film more sensitive to storage than D-speed dental film?

Two types of films with different speed, D-speed (Kodak Ultraspeed) and E-speed (Kodak Ektaspeed), were compared regarding film fogging under different storage conditions. The films were stored during one year at room temperature (+21 degrees C) without shielding, with 3 mm lead or with 200 mm iron shielding and in a refrigerator (+8 degrees C) without shielding. The films were processed in a standardised way and the film fog measured densitometrically each month. The film fog increased insignificantly with time for both film types under all storage conditions except in the refrigerator, where it reached unacceptably high levels and the faster film type (Kodak Ektaspeed) became unusable after 4 months storage in the refrigerator.

Radiography, Dental↗
PubMed1985

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.

Adolescent↗
PubMed1985

Accuracy of radiographic caries diagnosis at different kilovoltages and two film speeds.

Different kilovoltages (50, 60, 70, 90) and two films differing in speed (Kodak Ultra-Speed and Ektaspeed) were examined with regard to the diagnostic accuracy at detection of dental caries. Ten observers graded the occurrence of caries in radiographs of extracted premolars and their findings were compared with the actual presence or absence of caries. The ROC-technique was used to evaluate the results using the area under the curve as a measure of diagnostic accuracy. A significant difference was found between kilovoltages with better diagnostic accuracy for the lower kilovoltages. No significant difference was found between the two types of film. Our results suggest that a kilovoltage of 60 offers a proper balance between absorbed radiation dose and diagnostic accuracy. The use of Kodak Ektaspeed offers a diagnostic accuracy similar to that of Kodak Ultra-Speed.

Absorptiometry, Photon↗
PubMed1984

Radiation dosimetry in radiology of the temporomandibular joint.

The absorbed doses and energy imparted during conventional radiography and tomography of the temporomandibular joint were examined. Absorbed doses from the lateral-oblique transcranial projection and lateral tomography were low (0.02 to 7 mGy). From the axial projection the thyroid gland and salivary glands received a substantial dose (15 to 54 mGy) which was considerably decreased using an improved design of collimator. Radiation to the lens of the eye for the transmaxillary projection and for frontal tomography was 3 to 8 mGy. This can be reduced by a factor of 25 using lead-glass eye shields. The mean energy imparted from a bilateral examination of the temporomandibular joints using axial projection, four exposures for the transcranial lateral-oblique views, two exposures in the transmaxillary projection and lateral tomography views using a multi-film cassette was 34 mJ. The axial projection accounted for 50% of this figure.

Eye↗
PubMed1984

Clinical and radiologic six-year follow-up study of patients with crepitation of the temporomandibular joint.

Combined clinical and radiologic follow-up investigations of patients with temporomandibular joint (TMJ) crepitation are seldom seen in the literature. The aim of the present study was to clinically and radiologically re-examine twenty-four patients with TMJ crepitation six years after treatment was completed. Eleven patients initially had unilateral crepitation and thirteen bilateral. Symptoms and clinical signs were reduced. The localization of the condyle at intercuspal position as well as at maximum mouth opening was unchanged in the majority of the TMJs. Structural bone changes had existed in 30 of the 37 TMJs in 1974. The original structural bone changes were preserved in twenty of the TMJs, bone structure was altered in ten and six had remained normal. One normal TMJ developed structural bone changes. The most common alterations consisted of increased sclerosis in the mandibular fossa and disappearance of erosions in the condyle. Since the symptoms and signs were reduced and the radiological changes were small, the prognosis for patients with TMJ crepitation must be considered good.

Adolescent↗
PubMed1979

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.

Electromyography↗
PubMed1976

Radiography of the temporomandibular joint utilizing oblique lateral transcranial projections. Comparison of information obtained with standardized technique and individualized technique.

An individualized technique for radiography of the temporomandibular joint utilizing oblique lateral transcranial projection is described. The patient is fixed in a cephalostat and the central ray directed through the horizontal long axis of the condyle. The information yielded when applying the individualized technique has been compared with that yielded from a standard technique and tomography. The plane of sectioning for tomography was oriented perpendicular to the horizontal long axis of the condyle. The material comprised radiographs from 30 joints. The condyle to fossa relation was studied as well as the occurence of structural changes. Neither the individualized technique nor the standardized technique gave an accurate picture of the condyle to fossa relation when compared to tomography. However, the individualized technique tended to give the same result as tomography more often. Tomography revealed the greatest number of structural changes (66) followed by individualized technique (47) and standard technique (19). Most changes were noted exclusively in one projection. A combination of individualized technique and tomography revealed more changes than a combination of tomography and standard technique.

Humans↗