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Biomedical subjects

J E Ellingsen

Publications and source records attributed to J E Ellingsen.

9 recordsLinked to original sources
PubMed1991

A study on the mechanism of protein adsorption to TiO2.

The hypothesis that calcium ions adsorb to TiO2 and further to macromolecules with high affinity for Ca2+ was tested. The reaction of human serum proteins with TiO2 was examined and compared with the reaction with hydroxyapatite. The oxide covered titanium surfaces reacted with calcium when exposed to CaCl2 and calcium was identified to a depth of 17 nm into the oxide layer. Surface adsorbed serum proteins were dissolved by EDTA and analysis by the SDS-PAGE technique revealed that the surfaces of TiO2 and hydroxyapatite appeared to take up the same proteins selectively from human serum. Albumin, prealbumin and IgG were identified by immunoelectrophoresis. It is suggested that calcium binding may be one mechanism by which proteins adsorb to TiO2. It is well established that this is the case with hydroxyapatite.

Adsorption↗
PubMed1991

Chemical analysis and scanning electron microscopy of acquired pellicle formed in vivo on stannous fluoride treated enamel.

Stannous fluoride (SnF2) has been shown to be an effective caries preventive agent. After topical treatment of enamel surfaces, two reaction products have been demonstrated to precipitate on the surfaces, a larger type of globules, probably a calcium fluoride like product, and a smaller type of globules, probably a tin phosphate. The aim of the present study was to examine the amino acid composition and the formation of the acquired pellicle on SnF2-treated enamel in vivo. The chemical composition was examined by amino acid analysis of pellicle material collected in vivo from SnF2-treated enamel surfaces. Pellicle formation was examined by scanning electron microscopy on SnF2-treated enamel fragments carried in the mouth for 2 h. The results showed that pellicle material was formed in abundant amounts and covered the globular surfaces following the SnF2 treatment. The chemical analyses showed amino acid profiles with high content of acidic and neutral amino acids. The profiles were different from known amino acid profiles obtained from analyses of pellicle material collected from untreated enamel surfaces.

Amino Acids↗
PubMed1991

Induction of calcium phosphate precipitation by titanium dioxide.

Titanium powder and various titanium dioxides were tested for their capacity to reduce the induction time for calcium phosphate precipitation from supersaturated solutions. Only after a pretreatment aimed at increasing its oxide surface layer was titanium powder found to accelerate the precipitation from solutions containing 2 mmol/L CaCl2, 2 mmol/L KH2PO4, 50 mmol/L Hepes, pH 7.2, and to induce precipitation from metastable solutions containing 1.2 mmol/L CaCl2, 1.2 mmol/L KH2PO4, 50 mmol/L Hepes, pH 7.2, at 37 degrees C. Even stronger effects were found when suspensions of the titanium dioxides anatase or rutile (10-50 micrograms/mL) were added to these solutions. TiO2 appeared to serve as a reactive substrate for secondary nucleation at a wide range of calcium-to-phosphate ratios and concentrations, even in the presence of 40 mg/mL bovine serum albumin, which completely inhibited precipitation in control incubations. These results suggest that the oxide surface layer of titanium implants may induce calcium phosphate precipitation in the metal-to-bone interface, which may play a role in the integration of such implants in bone.

Calcium Phosphates↗
PubMed1991

[Frialit ceramic implants--a four-year follow-up study].

Sixty-two ceramic implants (Frialit) were installed in 53 patients with agenesia or loss of single teeth due to traumata or infection. Sixty-three per cent of the implants were operated in immediately after tooth extraction, whereas the rest were installed in a healed bony alveolar ridge. Eighty-five per cent of the implants were replacements for maxillary incisors. The average observation period was 4 years. During this period 10 implants were removed due to lack of osseointegration. Seven of these implants were lost in the healing period, the remaining 3 were removed after installation of the suprastructure. Eighty-four percent of the implants were successful after 4 years. Trauma in the maxillary region have caused fracture of the implants in 5 patients. Such incidents create therapeutic problems difficult to solve satisfactorily.

Aluminum Oxide↗
PubMed1987

Treatment of dentin with stannous fluoride--SEM and electron microprobe study.

The effect of SnF2-treatment of dentin surfaces was investigated by means of scanning electron microscopy (SEM) and electron microprobe analysis. Human dentin was treated with aqueous SnF2 solutions of concentrations varying from 1 to 10%. The treatment periods lasted for 1, 5, 10, or 60 min. Both tin and fluoride were identified on the surfaces. The concentration varied depending on the extensiveness of the treatment. Immersion in 1 M KOH for 15 h removed both tin and fluoride from the surfaces. This reaction was not observed after immersion in H2O for the same time period. Examination of the SnF2-treated dentin surfaces showed a dense layer of globular particles and in addition some larger particles. The dentinal tubules were totally covered even after the treatment with the lowest concentration of SnF2. Deposition of tin- and fluoride-containing globules on dentin surfaces may be of clinical interest. This layer may have importance both for the caries resistance of dentin and for hypersensitivity reactions.

Dental Caries↗
PubMed1986

Scanning electron microscope and electron microprobe study of reactions of stannous fluoride and stannous chloride with dental enamel.

Stannous fluoride but not stannous chloride has shown a caries inhibiting effect in animal studies. The effect of aqueous solutions of stannous fluoride and stannous chloride on dental enamel surfaces was investigated by scanning electron microscope and analytical electron microprobe. Some large globules and a continuous layer of small globules were observed after stannous fluoride treatment. The large globules were soluble in both water and alkali, whereas the small ones were only soluble in alkali. Both fluoride and tin were found to be present on the enamel surfaces by the electron microprobe after stannous fluoride treatment. The fluoride could not be detected after immersion in distilled water whereas alkali treatment removed the tin. The large fluoride-containing globules may consist of calcium fluoride as this substance is known to be slightly soluble in water and soluble in alkali. Stannous chloride treatment gave a layer of small tin-containing globules with properties similar to the layer formed on enamel treated with stannous fluoride. It is therefore suggested that the tin-containing layer is not associated with caries protection whereas calcium fluoride-like deposition on the enamel probably is a factor in the caries inhibition caused by stannous fluoride.

Dental Enamel↗
PubMed1985

Chemical plaque control and extrinsic tooth discoloration. A review of possible mechanisms.

The etiology of extrinsic tooth discolorations due to chemical, plaque-preventive agents is not fully understood. However, information from experimental investigations point to at least 3 possible mechanisms. (A) Non-enzymatic browning reactions (Maillard reactions). (B) Formation of pigmented metal (Fe, Sn)-sulfides. (C) Reaction products of food and beverage constituents and chemical, plaque-preventive compounds. Available evidence indicates that browning (A) and formation of pigmented metal sulfides (B) are the most likely causes of these discolorations while dietary factors (C) may play a modifying rôle.

Animals↗
PubMed1985

Plasma fluoride levels in man following intake of SnF2 in solution or toothpaste.

The degree and rate of fluoride absorption in five volunteers were studied after ingestion of SnF2 and NaF solutions or SnF2 toothpaste. The fluoride concentration in plasma was followed for eight hours. The relative bio-availability of fluoride was calculated and was similar for both the NaF and SnF2 solutions, although the latter solution showed a somewhat faster absorption rate. The bio-availability of fluoride from the SnF2 dentifrice was 85%.

Absorption↗