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Biomedical subjects

E C Rose

Publications and source records attributed to E C Rose.

7 recordsLinked to original sources
PubMed2005

Validation of speed of sound for the assessment of cortical bone maturity.

Bone changes its structural and physical properties during maturation. In order to validate ultrasound measurements with regard to their usefulness in assessing cortical bone maturation, speed of sound (SOS) data were compared with mechanical properties (elastic modulus, bending strength, and cortical surface hardness), density and water content. Thirty pig mandibles were selected from three different age groups. Rectangular specimens of the buccal cortical bone of the body of the mandible were prepared. SOS was measured with pulsed ultrasound at a frequency of 2 MHz in all three dimensions, bone mineral density (BMD) by quantitative computed tomography, breaking strength and apparent elastic modulus in a three-point bending test to failure, water content using the lyophilization technique, and micro-indentation hardness using a modified Vickers' technique. While SOS in all three directions, BMD, surface hardness, and bending strength increased significantly (P < 0.001), bone tissue water content decreased significantly (P < 0.001) with age. Changes in the elastic modulus were not significant. Changes in SOS in the antero-posterior and apico-occlusal directions can be partly explained by BMD. In a bucco-lingual direction the increase is inadequately explained by the physical parameters investigated, and has possibly to be attributed to structural differences. Maturation of the mandible implies changes in its architectural organization, in material composition, and in the mechanical properties of cortical bone. In vitro SOS measurements reflect different structural and physical properties that are all age dependent. It thus seems feasible that age-related changes in bone maturation could be monitored by SOS measurements.

Age Factors↗
PubMed2001

Occlusal side effects caused by a mandibular advancement appliance in patients with obstructive sleep apnea.

Mandibular advancement appliances (MAA) have been established as an alternative treatment option for obstructive sleep apnea (OSA). Although the therapeutic effect of these devices has been proven both clinically and polysomnographically through various studies, there are very few follow-up examinations in existence concerning possible dental side effects caused by the MAA. However, if lifelong treatment of OSA is considered, these follow-up examinations are of utmost importance. This article presents 2 cases with unexpected dental side effects and occlusal alterations caused by MAA therapy.

Activator Appliances↗
PubMed2000

Contribution to the biological assessment of orthodontic acrylic materials. Measurement of their residual monomer output and cytotoxicity.

The acrylic materials used in orthodontics for the fabrication of removable appliances are subjected in the oral cavity to processes of change which influence their physical, mechanical and biological properties. It is therefore essential that every newly developed material must be judged in terms of its clinical value. In the present study, 2 orthodontic cold-cure acrylics, Orthocryl and Forestacryl, and 4 orthodontic photocure acrylics, Triad, Wil-O-Dont, Odontolux and Lux-A-Tech, were investigated and compared with 2 prosthetic acrylic materials: the cold-cure acrylic Palapress and the hot-cure acrylic Paladon. The quantity of residual monomers from methyl methacrylate (MAA) or urethane dimethacrylate (UDMA) eluted from the sample in a given time after the processing was estimated by high pressure liquid chromatography (HPLC). The cytotoxic properties of the materials were examined by Mosmann's proliferation-inhibition test with an established culture of fibroblasts (= MTT test). The hot-cure acrylic Paladon produced by far the smallest amount of eluted residual monomer and the least growth inhibition in the MTT test. The prosthetic cold-cure acrylic Palapress achieved significantly better results than the orthodontic cold-cure materials Orthocryl and Forestacryl. The photocure acrylics released less UDMA than did the cold-cure acrylics MMA. In the cell culture test, all the orthodontic materials examined were assessed as "slightly cytotoxic"; the prosthetic acrylics were graded under ISO-standard 10993-5 as "noncytotoxic". After soaking the plastic material in water for 3 days its cytotoxic properties, as exemplified by the cold-cure acrylic Forestacryl and the photocure acrylic Triad, were reduced, and during the following investigation no more inhibition of growth was observed. It was possible to confirm with the tests used that, for Triad, it is necessary to carefully remove the oxygen-inhibition layer of the photocure acrylic in order to improve the biological properties. The influence of the plastic material on fibroblast cultures was assessed, among other methods, by the quantity of residual monomers liberated. These were significantly reduced after soaking the manufactured substance in water for 3 days. Careful laboratory treatment of the photocure acrylics is necessary in order to improve their biological properties.

Acrylic Resins↗
PubMed1998

In vitro investigation into the biological assessment of orthodontic wires.

The alloys used in orthodontics are subject in the moist environment of the oral cavity to various corrosion processes. If the products of the corrosion are introduced into a biological system they may cause changes. In the present investigation the corrosion rate of 23 different orthodontic wires (preformed arch wires and straight wires) made from 5 different alloys were examined in a nutrient medium by ICP-AES analysis, and the influence of the corrosion products on the cytotoxicity of a fibroblast culture was investigated using Mosmann's MTT test. The nickel-titanium wires Nitinol, Sentalloy and Original Chinese Wire and the beta-titanium alloy TMA had no effect on the rate of cell proliferation. Nor did stainless steel wires inhibit growth significantly, with the exception of Australian Wire and Wildcat Wire. The manganese-steel alloys Noninium h and Mezanium caused significant reductions in growth rate, which were attributed to the manganese ions released by the corrosion. The most severe growth inhibition was caused by the Co-Cr-Ni alloy Elgiloy, and this reaction is independent of the 4 levels of resilience. The degree of growth inhibition depended upon the concentration of corrosive cobalt and nickel ions in the eluate. In spite of the differences observed, all the orthodontic wires examined are graded under ISO-standard 10993-5 as "non-cytotoxic". The degree of toxicity was found to be determined essentially by the corrosion rate of the alloy and the cytotoxic characteristics of the resulting trace elements.

Animals↗