Biomedical subjects

A Petersson

Publications and source records attributed to A Petersson.

At least 37 records · Page 2Linked to original sources

PubMed1997

Cartilage matrix macromolecules in lavage fluid of temporomandibular joints before and 6 months after diskectomy.

The purpose was to investigate if antigenic fragments of aggrecan and cartilage oligomeric matrix protein (COMP) are detectable by enzyme-linked immunosorbent assay in lavage fluids from the temporomandibular joint (TMJ) and to examine if the relative content of these cartilage markers changes during development of osteoarthrosis (OA) after diskectomy. Lavage fluid was obtained at surgery and 6 months postoperatively in 13 patients. Computed tomography or magnetic resonance imaging was without evidence of hard-tissue changes prior to surgery in all patients. In 9 of the patients, sufficient material for analysis was obtained at both examinations. Aggrecan and COMP were detectable in all but 2 fluids, in which the COMP levels were below detection limit. The aggrecan/COMP ratio increased in all 9 patients during the 6-month period, indicating increased release of aggrecan relative to COMP fragments. The changed aggrecan/COMP ratio possibly reflects increased cartilage turnover during development of OA. Changes compatible with OA were present on computed tomography in all cases at the 6-month follow-up. This study shows that the lavage procedure is feasible for obtaining synovial fluid from the TMJ for immunochemical analyses of tissue-derived macromolecules.

Adolescent↗

PubMed1997

Bone volume in human temporomandibular autopsy joints with and without erosive changes.

The aim was to compare the trabecular bone volume (TBV) and the total bone volume (TOBV) of human temporomandibular joints (TMJ) with erosive changes with those of joints without erosive changes. We examined 35 TMJ autopsy specimens from 19 individuals aged 66 88 years. Sagittal sections of the joints were analyzed microscopically for erosive hard-tissue changes. The TBV and the TOBV of the sections were assessed with the aid of computerized image analysis. A significant increase in trabecular and total bone volume was found in condyles with erosive changes (TBV = 21%, TOBV = 54%) as compared with condyles without erosive changes (TBV = 15%, TOBV = 40%). The trabecular bone volume of the temporal component was also increased (TBV = 24%) in joints with erosive changes in the condyle as compared with joints with unaffected condyles (TBV = 16%). The findings indicate that the relative bone mass may play a role in the development of erosive changes in the TMJ.

Age Factors↗

PubMed1997

The arginine-nitric oxide pathway in thrombotic microangiopathy.

Eleven patients with thrombotic thrombocytopenic purpura (TTP) or haemolytic uremic syndrome (HUS) were investigated with respect to plasma concentrations of L-arginine, a substrate for nitric oxide (NO) and asymmetrical dimethyl arginine (ADMA), during active disease and after recovery. Plasma concentration of NO3-, the degradation product of NO, was also analyzed. The patients were treated with fresh-frozen plasma and plasmapheresis. One of the patients had experienced relapses of TTP five times during the preceding year. After treatment with p.o. arginine hydrochloride 1.5 g x 3 was started, no relapse has occurred during a 12-month period. During the active phase the plasma concentration of arginine was low and that of NO3- was very high, indicating a high NO-synthesis rate. The arginine concentration normalized on recovery. Plasma levels of ADMA, was twice normal during active disease, and did not return to normal on recovery. In conclusion, patients with TTP/HUS exhibit signs of activation of the NO-synthesis.

Adult↗

PubMed1996

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.

Aged↗

PubMed1996

Quantitative computed tomography of trabecular bone in the mandible.

OBJECTIVE: To evaluate the potential use of quantitative computed tomography (QCT) for the assessment of bone mineral density of the edentulous mandible prior to implant placement. METHODS: Ten 2 mm thick CT slices of anterior and posterior edentulous sections from 15 mandibles were obtained perpendicular to the buccal and lingual plates. The bone mineral density, expressed as the amount of calcium hydroxyapatite (mg cm-3) of the trabecular bone, was calculated using a method that takes into account the influence of fat. RESULTS: The variation of bone mineral density between mandibles was high. Anterior sections showed higher values than posterior sections and a variation was found within sections of the same mandible. CONCLUSION: CT provides a site-related measure of the bone mineral density in the mandible and appears potentially useful as a non-invasive method to determine a parameter that may reflect bone quality prior to implant placement.

Aged↗

PubMed1996

Concavity of the posterior surface of the temporomandibular condyle: clinical cases and autopsy correlation.

OBJECTIVES: To elucidate the significance of the radiographic finding of a concavity of the posterior surface of the temporomandibular condyle. METHODS: Three clinical cases with a concavity were followed up clinically and radiographically. A total of 39 temporomandibular joint (TMJ) autopsy specimens were examined by corrected sagittal tomography and seven condyles with a concavity of the posterior surface found. They were analysed microscopically together with three joints with a normal, rounded condyle. RESULTS: At follow-up tomography, two of the clinical cases revealed no change while the third patient had erosive changes after 7 months. The microscopic findings of the autopsy specimens varied. The articular cartilage in three of the seven joints with a concavity was similar to that in the normal condyles. The outer surface of the articular cartilage was sometimes uneven and the cartilage thickened, with an irregular junction between the articular cartilage and subchondral bone. In three joints the cartilage in the concavity had been replaced by granulation tissue. All seven joints had increased cellular activity in the concavity. CONCLUSIONS: The radiographic finding of a concavity in the posterior surface of the condyle is not specific. When small and well-defined it is indicative of remodelling and of osteoarthrosis when larger and with a diffuse outline.

Adult↗

PubMed1996

Evidence-based evaluation of three imaging methods for the temporomandibular disc.

OBJECTIVES: To review the literature and evaluate the evidence for the diagnostic outcome of arthrography, computed tomography (CT) and magnetic resonance imaging (MRI) in the assessment of temporomandibular joint (TMJ) disc position. METHODS: A literature search from 1978 to 1994 was conducted. Data on sensitivity, specificity, predictive values and likelihood ratios were collected and, if not available, calculated for each imaging method. Measures of observer performance were also recorded. RESULTS: In total, more than 400 publications were retrieved on imaging of TMJ disc position, 219 on arthrography, 99 on CT and 147 on MRI, with a marked decrease in recent years. The majority of the publications (54%) presented series of patients. The diagnostic outcome cold be obtained from only 7% of the studies and the observer performance from only two of these. Arthrography had the highest diagnostic outcome for the diagnosis of anterior disc position; sensitivity 0.90, specificity 0.80, positive predictive value 0.88 and negative predictive value 0.82. Corresponding figures for CT were 0.66, 0.68, 0.66 and 0.74 and for MRI 0.86, 0.63, 0.67 and 0.83. The diagnostic outcomes expressed as the likelihood ratios for positive test outcome were 4.5 for arthrography, 2.3 for MRI and 2.1 for CT. The outcomes in diagnosing sideways and rotational displacements were higher for MRI (sensitivity 0.81, specificity 0.87, positive predictive value 0.82, negative predictive value 0.88) than for arthrography (0.64, 0.83, 0.70, 0.79). The likelihood ratios were 6.2 for MRI and 3.8 for arthrography. The interobserver performance ranged between moderate to substantial for arthrography and was almost perfect for MRI. CONCLUSIONS: Based on current evidence on the diagnostic outcome, MRI seems to be the method of choice for diagnosing TMJ disc position. Arthrography has a higher diagnostic outcome for anterior disc position but the disadvantage of being an invasive method. We suggest that the quality of the evidence should be improved and that an analysis of the impact of the imaging methods on patient treatment should be performed.

Arthrography↗

PubMed1996

Energy dispersive X-ray microanalysis of the dentin in rat molars after corticosteroid treatment.

The aim of this study was to investigate whether the calcium (Ca) and phosphorus (P) composition of corticosteroid induced dentin was the same as in normally developed dentin. Seven rats were given corticosteroids intravenously and three rats served as controls. Energy dispersive X-ray microanalysis (EDX) was carried out on the axially sawn roots of the molars. Measurements were made at 20 sites, equally distributed in the buccal, mesial, lingual and distal direction. The results showed that the Ca/P ratio (weight %) was slightly above 2.0 in both the experimental and the control group, indicating that the corticosteroid induced dentin had a normal Ca/P ratio. However, different degrees of mineralization were found in different directions of the roots.

Adrenal Cortex Hormones↗

PubMed1995

Disk displacement and temporomandibular joint symptoms in orthognathic surgery patients.

The purpose of this study was to document the prevalence of disk displacement and temporomandibular joint symptoms in orthognathic surgery patients. Fifty-three consecutive patients with different types of dentofacial anomalies were examined clinically and with bilateral arthrography. Disk displacement unilaterally or bilaterally was found in 57% of the patients or 46% of the joints. Displacement with reduction was seen in 38 joints, and displacement without reduction was seen in 11 joints. Fifty-three percent of the patients had pain in the temporomandibular joint or masticatory muscles, 30% of the joints demonstrated clicking, and 4% had crepitation. No association was found between disk displacement and clinical symptoms except for an association between clicking and anterior disk displacement with reduction. Neither could an association between disk displacement and the type of dentofacial anomaly be appreciated. It was concluded that disk displacement was frequent in patients with dentofacial anomalies, but no relationship to temporomandibular joint symptoms and the type of dentofacial anomaly could be clearly demonstrated.

Adolescent↗

PubMed1995

Measurements of distances related to the mandibular canal in radiographs.

Before implant surgery in the mandibular side segment, it is of utmost interest to locate the mandibular canal in radiographs to avoid interference with the neurovascular bundle during surgery. Six mandibular specimens were radiographically examined with 2 panoramic and 3 tomographic techniques. The distances between the superior border of the canal and the alveolar crest and between the mandibular base and the inferior border of the canal were measured. In addition, the height of the canal was measured. The measurements were performed by 3 or 4 observers and compared with measurements on contact radiographs of the same areas. Tomography gave more accurate values of the above distances than panoramic techniques. The variation between observers in detecting the mandibular canal was large.

Aged↗

PubMed1995

Follow-up examination of the temporomandibular joint disk after splint therapy by magnetic resonance imaging--a case report.

A 38-year-old female patient presented with temporomandibular joint (TMJ) pain, bilateral clicking and intermittent locking. The patient was treated with a splint in order to decrease the symptoms and to obtain a proper disk-condyle relationship. The effect of the splint therapy was investigated after one month and after one year and five months using magnetic resonance imaging (MRI) with splints in place. After treatment for one year and six months, the clicking sound of the right TMJ disappeared, and she became free from locking. With the aid of MRI, it was found that the disk of the right TMJ had changed from an anterior position with reduction to a superior position. In the left TMJ, the disk changed from an anterior position without reduction to an anterior position with reduction. MRI gave important information on the disk position and the efficacy of the splint therapy.

Adult↗

PubMed1995

Clinical and radiological findings related to treatment outcome in patients with temporomandibular disorders.

OBJECTIVES: To test the hypothesis that the outcome of temporomandibular disorders (TMD) is not influenced by condylar position, asymmetry, angle or structural bone changes. METHODS: Eighty consecutive patients (60 women, 20 men) with an age range of 6-81 years, referred to the Department of Stomatognathic Physiology, were included in the study. The patients were clinically and radiologically examined before and at least 1 year after treatment. RESULTS: The most common clinical diagnoses among the patients were TMD with a neuromuscular background in 35% and osteoarthritis in 21%. Seventy-two per cent of the patients were symptom-free or better, 24% unchanged and 1% worse 1 year or more after treatment. After treatment the bone structure of the TMJ was unchanged in 83% of the patients, in 12% erosions healed and in 5% erosions developed. Almost all patients had some degree of condylar displacement on tomography before treatment. In the majority the condylar position was unchanged after treatment. CONCLUSION: No single radiographic finding was found to be related to the treatment outcome and therefore plain radiography has a minor role in the management of TMD.

Adolescent↗

PubMed1995

Temporomandibular joint disc position in arthrography. A descriptive analysis of the observer performance.

OBJECTIVES: To explore the relationship between the use of diagnostic cues and observer performance in the diagnosis of the temporomandibular joint (TMJ) disc position. METHODS: Thirty arthrographic examinations using fluoroscopy alone and combined with either transcranial radiography or tomography were selected. Seven observers assessed the examinations with the aid of reference images and written diagnostic cues for three disc diagnoses. After one month three of the observers repeated the assessments and noted how they applied the diagnostic cues. Later, they made a consensus report on how the cues were applied to each joint. RESULTS: The seven observers agreed unanimously with the reference diagnosis by fluoroscopy alone in 11 joints and in 14 when supplemented with transcranial radiography or tomography. Seven joints were given three different diagnoses by the seven observers when fluoroscopy was used alone and five when supplemented with transcranial radiography or tomography. The cues were applied with confidence in those joints where the observers were unanimous but in those with three different diagnoses, the anatomical features described in the cues were difficult to identify or the findings were ambiguous as they did not match the cues. CONCLUSIONS: It appears difficult to define radiographic cues applicable to all TMJ disc positions.

Arthrography↗

PubMed1995

Questionnaire survey on the use of dental X-ray film and equipment among general practitioners in the Swedish Public Dental Health Service.

A questionnaire was sent to all clinics in the Public Dental Health Service in Orebro County in 1989 and 1993. The survey comprised questions about X-ray film and developing technique. The questionnaire of 1993 was accompanied by questions on the type of dental X-ray film and collimator each dentist used, altogether 175 dentists. The results showed that Kodak Ektaspeed dental X-ray film was used by 53% of the dentists in 1993. The mean number of months to the expiry date for all film packages irrespective of film type increased from a mean of 7.5 months to a mean of 13 months from 1989 to 1993. Only 11% of the Ektaspeed film packages in 1989 had a base plus fog < or = 0.25, whereas the figure in 1993 was 30%. Rectangular collimation adjusted to the size-2 film (31 mm x 41 mm) was used by 36% of the dentists in 1993. In 1993, 88% of the clinics used automatic processing, and in 85% of the clinics both automatic and manual processing was used. The processing time and temperature varied greatly for both automatic and manual processing. The results indicate that film and developing procedures in Swedish general dental practice are not always in accordance with the recommendations and guidelines of the Swedish National Radiation Protection Institute (SSI) and that attempts should be made to improve dentists' behavior with regard to radiation safety. A major dose reduction would be achievable without jeopardizing diagnosis if the regulations of the SSI were followed by using the fastest available film and optimum developing procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Filtration↗

PubMed1995

Corrected sagittal tomography of the temporomandibular joint. Influence of errors in film and patient positioning on linear and angular measurements.

The aim of this study was to assess the variation in film and patient positioning in horizontally corrected sagittal tomography of the temporomandibular joint (TMJ). The influence of this variation on linear and angular measurements of some anatomic structures of the TMJ was also studied. There was no significant variation in film positioning in the tomograph, using a multi-film cassette. The variation in positioning the patient in the tomograph was significant when four dental assistants were asked to place the Frankfort plane parallel to the horizontal plane. The measurements with the film in a straight position were compared with the measurements with the film angulated, to simulate the mean variation in film and patient positioning. Linear and angular measurements of anatomic structures were performed in arthrotomograms of 58 joints, representing joints with superior disk position and joints with anterior disk position with and without reduction. There was a difference between the two measurements for four different distances and one angle independent of diagnosis. No differences could be found between patients belonging to the different diagnostic groups. The results indicate that variation in patient positioning influences linear and angular measurements of anatomic structures in TMJ arthrotomograms.

Analysis of Variance↗

PubMed1994

Observer performance and diagnostic outcome in diagnosis of the disk position of the temporomandibular joint using arthrography.

Observer performance and diagnostic outcome in the diagnosis of the disk position of the temporomandibular joint by arthrography were investigated. Three different radiographic techniques were studied: fluoroscopy, fluoroscopy in combination with lateral transcranial radiography, and fluoroscopy in combination with corrected sagittal tomography. Seven observers were asked to assess 30 joints representing three diagnoses, namely superior disk position and anterior disk position with and without reduction. The intraobserver agreement was high for all three techniques. The interobserver agreement of the seven observers when the disk position was diagnosed by fluoroscopy in combination with lateral transcranial radiography (Kappa index 0.68) was higher than that with fluoroscopy alone (Kappa index 0.54) and that with fluoroscopy in combination with corrected sagittal tomography (Kappa index 0.56). The sensitivity, specificity, and predictive values of fluoroscopy in combination with lateral transcranial radiography were also higher than those of the other radiographic techniques. Judged from this study, the observer agreement and the diagnostic outcome for arthrography with the use of the three examined techniques are high when well-defined criteria and reference images are applied.

Adolescent↗

PubMed1994

No short-term difference in outcome after temporomandibular joint arthrography alone or with immediate lavage.

Thirty-three patients with an arthrographically documented anterior disk displacement without reduction were randomly assigned to be treated with upper joint space lavage or to serve as controls in an 8-week clinical trial. Pain was evaluated by the patients on a visual analog scale at rest and after chewing gum. The clinical examination followed a standardized protocol. Improvements in pain and mouth opening were found in both the lavage and control group after 8 weeks, but there were no statistically significant differences between the treatment and control groups. It was concluded that upper joint space lavage after arthrography seems to be ineffective to decrease pain and to increase mouth opening in patients with anterior disk displacement without reduction.

Adult↗

PubMed1993

Effect on human teeth of renal transplantation: a postmortem study.

Extracted teeth from five deceased patients treated by renal transplantation were examined radiographically and histologically, and compared with teeth from healthy persons of approximately the same age. In three of the patients with a renal transplant, the radiographs showed normal pulp chamber sizes, but histologic examination revealed a widened predentin zone, approximately four times greater than in the controls. In two of the patients the radiographs showed marked reduction of the pulp chamber size. The histologic changes of these teeth were mainly an extensive amount of secondary dentin along the pulp chamber walls and the root canals, with a markedly reduced pulp space. One explanation for the difference between the patients was that patients with extensive pulp calcifications were given a higher total amount of corticosteroids than patients with a widened predentin zone.

Adult↗