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Biomedical subjects

R Söremark

Publications and source records attributed to R Söremark.

At least 19 recordsLinked to original sources

Titaniumtetrafluoride for treatment of hypersensitive dentine.

Dentine hypersensitivity in cervical areas and severe dentine sensitivity in teeth prepared for restorations were treated with a titaniumtetrafluoride solution. Patients included in the study complained spontaneously about the sensitivity in intact dentine surfaces. Thirty patients with at least one tooth on each side of the maxilla and/or mandible experiencing moderate or severe sensitivity in cervical areas participated. The degree of sensitivity was determined by scraping an explorer over the dentine surface and by air blast. At least one sensitive tooth on one side of the jaw was treated with titaniumtetrafluoride, and one on the contralateral side with a placebo solution. Results were recorded after one month, four, eight and twelve months, using the explorer and the air blast. A total of 102 teeth, of which 51 were controls, were treated. About 80% responded to the treatment with the titaniumtetrafluoride solution after one month and 55-84% thereafter. No response occurred in any of the placebo-treated teeth. Twenty patients with severe sensitivity in dentine of teeth prepared for crowns were also treated with the titaniumtetrafluoride solution when trying casts and crowns and before cementation. A total of 52 teeth were treated. Desensitizing effects occurred in 75% of the patients, with 36 of the 52 prepared teeth.

Adult

Influence of phytic acid on zinc phosphate cement.

The influence of phytic acid on the properties of zinc phosphate cement was studied by adding 2-13 wt% phytic acid to the liquid. Improved mechanical strength and stability were found for some cements prepared from commercial powders when liquids with increased phytic acid content were used. The results indicate that the formation of increased amounts of zinc phytate has a favorable effect on the properties of zinc phosphate cement.

Aluminum

Abrasion of acrylic veneers by simulated toothbrushing.

The abrasion responses were tested on four acrylic veneer materials, K + B Plus, K + B 75, Isosit, and Ivocron. The studies were performed in two independent research laboratories. Two different brushing machines were used with an abrasive slurry. The results were used for comparing the degree of abrasion for the resin materials. Three analytical methods of measuring the degree of abrasive wear were used: surface profile measurement, microscopic evaluation, and measurement of loss of volume. Isosit showed the best abrasion resistance of the four materials tested.

Acrylic Resins

Nickel allergy and nickel-containing dental alloys.

Test pieces from five cobalt-chromium casting alloys intended for use in removable partial dentures were attached to the skin of 10 women with known allergy to nickel. Patch tests were also performed with nickel and cobalt salts. Nine of the 10 women showed clear-cut or strong patch test reactions to the alloy with 7% nickel, one patient also to one of the other alloys (less than 1% nickel). In five patients with contact allergy reactions to both nickel and cobalt salts mild or marked responses to some of the other alloys were observed. Corresponding observations were made in three out of the five patients with contact allergy reactions to nickel salt but not cobalt salt.

Adult

Uranium content in porcelain denture teeth and in porcelain powders for ceramic crowns.

Some porcelain denture teeth and porcelain powders marketed in Sweden haven been analyzed for the content of uranium. The fission track method and the delayed neutron technique were the methods used. Compared to results published previously the content of uranium was generally found to be lower in the brands analyzed. The denture teeth contained 23-186 ppm for Anatoform, 35-137 ppm for Myerson, 15-45 ppm for Candulor G and 20-53 ppm for Vivopearl. The baked and fired porcelain powders showed values of about 2.8 ppm at most, those in the form of powder about 25 ppm at most. The radiation dose to the mucosa of the upper lip was calculated and is discussed.

Crowns

The distribution of nickel in mice. An autoradiographic study.

Metallic restorations are corroded in the oral environment. Corrosion products penetrate into the tissues and are distributed throughout the body seeking certain organs and tissues as targets. The distribution patterns of nickel in albino mice were studied autoradiographically at various periods after an intravenous injection of 63Ni in order to locate the target organs and tissues of nickel. With short survival periods the highest uptake of 63Ni was found in the blood, kidney, urinary bladder, lung, eye and hair follicles. With long survival periods, 3 weeks, the distribution pattern was dominated by high uptake in the lung tissues, central nervous system, kidneys, hard tissues and skin. The distribution pattern in brown mice was similar to that in albino mice. However, the concentration in the eye and the skin was more pronounced. The importance of release of nickel from nickel containing dental alloys in nickel allergic patients is discussed.

Animals

Tissue accumulation of nickel released due to electrochemical corrosion of non-precious dental casting alloys.

Specimens of four non-precious dental casting alloys intended for use in the ceramic-metal technique were implanted subcutaneously in the neck region of mice. The animals were killed after 5 months. Organs and tissues were tested as regards the concentration of nickel by means of atomic absorption spectrophotometry. The study showed that due to electrochemical corrosion nickel was released from implants and accumulated in some tissues and organs.

Animals

Autoradiographic study of distribution patterns of metals which occur as corrosion products from dental restorations.

Radioactive chromium, cobalt, gold and mercury, all of which may occur as corrosion products from dental restorations, were injected in single doses via the tail vein of mice and an in vivo analysis of their distribution was performed using whole-body autoradiography. Gold seemed to be inert and went mainly to the liver and bones. The other elements studied were distributed widely in the body and remained for a long period of time in specific target organs and tissues.

Animals

Some thoughts on dental education.

It is suggested that immediately after dental school there should be a pre-registration year--a whole year of clinical training and instruction in general practice under the close supervision of a competent general practitioner/teacher. This year should end with a period of 3--4 weeks at the dental school for feedback discussion, seminars and some examinations. In order to involve every dentist, teacher, therapist, hygienist, assistant technician in a well-planned continuing educational program it seems necessary to introduce a compulsory system. It is also suggested that there should be a control system for the quality of care and individual professional performance. The demand for dental care increases. It is therefore highly desirable to utilize modern preventive measures on a broad scale, more effective and careful planning of the dental services for the individual patient and for the community as a whole and increased quality of treatment in order to reach a better prognosis and more ancillary personnel.

Curriculum

Dissolution and uptake of cadmium from dental gold solder alloy implants.

Pure metallic cadmium was irradiated by means of thermal neutrons. The irradiated cadmium (115Cd) was placed in bags of gold foil and the bags were implanted subcutaneously in the neck region of mice. Two and 3d respectively after implantation the mice were killed, the bags removed and the animals subjected to whole-body autoradiography. The autoradiograms revealed an uptake of 115Cd in liver and kidney. In another experiment specimens of a cadmium-containing dental gold solder alloy, a cadmium-free dental casting gold alloy and soldered assemblies made of these two alloys were implanted subcutaneously in the neck region of mice. The animals were killed after 6 months; cadmium analysis showed significant increases in the cadmium concentration in liver and kidney of those mice which had been given implants of gold solder alloy. The study clearly shows that due to electrochemical corrosion cadmium can be released from implants and accumulated in the kidneys and the liver.

Animals