Biomedical subjects

S Karlsson

Publications and source records attributed to S Karlsson.

294 records · Page 17Linked to original sources

PubMedDate not supplied

A clinical evaluation of ceramic laminate veneers.

The objective of this study was to make a clinical quality evaluation of resin-bonded ceramic veneers placed in general practice. Ceramic veneers were evaluated by four independent examiners according to the California Dental Association guidelines for evaluation of dental care. In addition, bleeding and margin index and mode of tooth preparation were recorded. None of the veneers had been replaced and only two had fractured. Almost all veneers received a satisfactory rating regarding surface, color, and margin integrity. More than half of the veneers had a satisfactory anatomical form. The bleeding index was comparable to that reported for other types of crowns. An equigingival or subgingival margin was most common.

Adolescent↗

PubMedDate not supplied

Recording of masticatory mandibular movements and velocity by an optoelectronic method.

In an assessment of the reproducibility of three-dimensional masticatory movements by an optoelectronic method, the tests conducted on the same individuals at different times produced results that were almost identical. However, some significant differences were found in the mandibular movement parameters when the subjects chewed different foods. This was mainly reflected in a longer opening time and higher values for the traversed 3D distance during mastication of chewing gum compared to peanuts. A movement analysis system was linked with a computer, and a program was developed for analysis of chewing parameters including mandibular velocity and dimensions. A reference system compensated for head movements. Every step in the recording procedure--calibration, collection, processing and presentation of the data--can be automatically controlled by the computer. The method proved to be precise and accurate in repeated recordings and apparently suitable for objective posttreatment and long-term evaluation of chewing performance.

Computer Systems↗

PubMedDate not supplied

High prevalence of coronary heart disease in patients with intermittent claudication. A preliminary report.

Twenty-five men aged 53-70 years, with stable intermittent claudication and similar symptoms and walking distance, were investigated with myocardial scintigraphy, duplex ultrasonography of carotid arteries and femoral angiography. Each patient was scored according to the degree of stenosis in the popliteal trifurcation and the aortoiliac and carotid arteries. Eighteen of the 25 men had coronary heart disease, which was clinically evident in nine cases and scintigraphically demonstrated in 17/24. Ischemia or infarction without clinical manifestation was located in the atrio-ventricular septal region in all nine cases. Eight of the 25 patients were shown to have carotid lesions. Significant correlation was found between lesions in the trifurcation and in the carotid arteries, but not between aortoiliac and carotid lesions. Trifurcational disease was a somewhat weaker marker for coronary heart disease. The high prevalence of coronary heart disease is noteworthy, especially the septal pathology, and further studies on the clinical significance of the findings appear to be urgently required.

Aged↗

PubMedDate not supplied

Changes of masticatory movement characteristics after prosthodontic rehabilitation of individuals with extensive tooth wear.

The masticatory cycles of 11 men (mean age 51.5 years) with extensive tooth wear were investigated before and after rehabilitation with fixed partial dentures. Parameters such as the tooth wear index (IA) and masticatory mandibular movement were recorded. Before treatment, the patients were also given a questionnaire related to possible background factors of importance to tooth wear. At baseline a mean score of 48.6 (range 0 to 100) for the tooth wear index (IA) was found. The clinical recall examination 3 years after prosthodontic rehabilitation displayed obvious wear of restorative material for two patients, and, in another patient, one of the fixed partial dentures had to be remade because of fracture of abutment teeth. Following rehabilitation, the duration of the masticatory mandibular opening movement increased and mandibular movement velocity decreased. The mandibular closing angle, near to occlusal contact, became steeper after prosthodontic treatment, indicating a changed mandibular movement pattern.

Adult↗

PubMedDate not supplied

Microhardness and surface topography of a composite resin cement after water storage.

PURPOSE: The aims of this study were to assess changes in the microhardness and surface roughness of a dual-cured composite resin cement after water storage for different periods of time. MATERIALS AND METHODS: Sixty specimens were divided into four groups comprising high- and low-viscosity cement specimens stored either dry or in water for 1 to 60 days. Microhardness and surface roughness measurements were made after 1, 7, and 60 days of storage. RESULTS: It was found that that although interactions complicated the interpretation of the results, the water-stored samples had a significantly lower microhardness compared to the dry-stored specimens for every time interval. In addition, the high-viscosity specimens had a significantly higher microhardness compared to the low-viscosity specimens. An increased microhardness was found for all groups, except for the low-viscosity, water-stored specimens after 60 days of water storage, which was attributed to an effect of the chemical postcuring process. Although difficult to evaluate from a clinical point of view, the laser profilometry analysis revealed that a significantly increased surface roughness was found after water storage and increased storage time that was possibly caused by a deterioration of the resin-matrix surface. CONCLUSION: For the permanency of the interfacial luting material, a high microhardness value seems to be important.

Analysis of Variance↗

PubMedDate not supplied

Success rate and failures for fixed partial dentures after 20 years of service: Part I.

PURPOSE: The objective of this study was to identify failures and to assess rate for fixed partial dentures constructed 20 years earlier by general practitioners in Sweden. MATERIALS AND METHODS: The original group consisted of 164 patients who had received prosthodontic treatment in 1974 comprising fixed partial dentures with at least five units. They had all been selected at random from the files of the Swedish Federal Dental Insurance Register. Twenty years later, 98 of them could be located and 72 of them agreed to participate in a clinical examination. The majority of drop-outs of the original group had died, could not be traced, or could not participate because of medical reasons. The examination focused on removed prostheses and/or units and a number of other clinically valid variables that will be reported in a forthcoming article. The 26 patients not participating in the clinical examination were interviewed by telephone. RESULTS: The examined participants had a total of 140 fixed partial dentures, 557 retainers, and 383 pontics still in service. When the number of failed and removed prostheses was calculated, a cumulative success rate of 65% was found, i.e., one third had been lost since 1974. There was no difference in failures between fixed partial dentures with or without cantilevers during the previous 8 years compared to the first 12 years in service. Loss of retention together with periodontal and esthetic problems, wear, and discoloration of acrylic veneers were the most frequently reported reasons for removal. CONCLUSIONS: The cumulative success rate for fixed partial dentures placed in 1974 was 65%. Failed prostheses had in most cases been replaced by a new fixed partial denture.

Adult↗