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In this study, we report on the inactivation technique to apply the oral surgery by micro low-temperature and atmospheric-pressure plasma irradiation utilizing a capillary nozzle. Emission spectrum of the micro-plasma showed OH and O radical, which were affected inactivation of coliform. Vibration temperature of the micro-plasma with 7998 K was calculated from peak-intensity at emission due to N22nd positive system. Inactivation region was larger than plasma irradiation spot, and it was increasing with plasma irradiation time.

Bisphenol A (BPA) is a common ingredient in dental materials. However, its potential adverse effects on the oral cavity are unknown. The purpose of this study is to identify the genes responding to BPA in a human oral epithelial cell line using DNA microarray. Of the 10,368 genes examined, changes in mRNA levels were detected in seven genes: five were up-regulated and two were down-regulated. The expression levels of the calcium channel, voltage-dependent, L-type, alpha 1C subunit (CACNA1C), cell death activator CIDE-3 (CIDE-3), haptoglobin-related protein (HPR), importin 4 (IPO4), and POU domain, class 2 and transcription factor 3 (POU2F3) were significantly up-regulated in the cells exposed to 100 mM BPA. The spermatogenesis-associated, serine-rich 2 (SPATS2) and HSPC049 protein (HSPC049) were significantly down-regulated. The detailed knowledge of the changes in gene expression obtained using microarray technology will provide a basis for further elucidating the molecular mechanisms of the toxic effects of BPA in the oral cavity.

In this study, we report on the biocidal activity technique by needle helium plasma irradiation at atmospheric pressure using borosilicate capillary nozzle to apply for the oral surgery. The diameter of needle plasma was less than 50 m, and temperature of plasma irradiated area was less than body temperature. Needle plasma showed emission due to OH and O radical. Raman spectra and methylene blue stain showed yeast cells were inactivated by needle plasma irradiation.

A magnetized coaxial plasma gun (MCPG) is here utilized for deposition on high-melting-point metals. MCPGs have hitherto been studied mostly in the context of nuclear fusion research, for particle and magnetic helicity injection and spheromak formation. During spheromak formation, the electrode materials are ionized and mixed into the plasmoid. In this study, this ablation process by gun-current sputtering is enhanced for metallic thin-film generation. In the proposed system geometry, only ionized materials are electromagnetically accelerated by the self-Lorentz force, with ionized operating gas as a magnetized thermal plasmoid, contributing to the thin-film deposition. This reduces the impurity and non-uniformity of the deposited thin-film. Furthermore, as the ions are accelerated in a parallel direction to the injection axis, vertical implantation of the ions into the substrate surface is achieved. To test a potential application of the developed system, experiments were conducted involving the formation of a buffer layer on hard ceramics, for use in dental materials.

We have investigated the control of photocatalytic behavior under deposited conditions of non-sintered target of different molar ratios with TiO 2 and La 2 O 3 from 1:0 to 1:2 for heavily La doping, and post-annealing temperature from 600 °C to 1000 °C for crystallizing by pulsed laser deposition. We have successfully crystallized heavily La-doped TiO 2 films with post-annealing temperature over 800 °C and with molar ratio of TiO 2 :La 2 O 3 over 1:1 on a quartz substrate. Heavily La-doped TiO 2 films are observed the decomposition of methylene blue and a water-splitting reaction in photocatalytic behavior under Xe light irradiation. When stoichiometric La-doped TiO 2 (TiO 2 :La 2 O 3 = 1: 1) is synthesized with heat-treatment at 900 °C, the best results are obtained under photocatalytic behavior and pure La 2 Ti 2 O 7 crystalline were obtained.

We studied the thermal properties of cavity liners that included calcium phosphate as inorganic filler, in contrast to the conventional pulp capping agents. Therefore, thermal diffusivity, specific heat capacity, and thermal conductivity were measured. In addition, thermal conductivity results were compared with those of restorative materials and human dentin to examine thermal insulation effects. The thermal conductivity of cavity liners ranged from 0.23 to 0.28 W m(-1) K(-1), and that of pulp capping agents ranged from 0.44 to 0.48 W m(-1) K(-1). Test results indicated that the thermal conductivity of cavity liner was lower than those of human dentin, pulp capping agent, cast alloy, and composite resin for restoration, hence suggesting that cavity liner has a good thermal insulation effect.

We have developed a technique for a higher degree of polymerization at the deep area of dental restorative resins by argon ion laser irradiation. We provide an analysis of the resin materials by Raman spectroscopy and Fourier transform infrared spectroscopy.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Light-activated dental composite resins undergo polymerization and curing by free-radical initiation like auto-cured resins. We studied the polymerization and curing properties of some commercially available light activated composites by using argon-ion laser.Results are summarized as: (1) The volume of a cured resion is dependent on the wavelength, and the maximum volume is obtained at 466 and 477 nm; (2) The volume of the cured resin increases with increasing irradiation power and time; (3) The rate of polymerization shrinkage gradually increases, before the saturation and (4) A correlation was observed between light transmittance and polymerization shrinkage for the composites of hybrid and traditional types which are relatively highly filled, but not for MFR type resins containing less micro-filler.

The temperature rise was monitored during the exothermic polymerization reaction of 5 selected visible light-activated composite resins cured with 5 activator lights. In general, temperature peaks occurring at curing times of less than 31 s were higher than those peaks occurring between 31 and 60 s of cure. The speed of the exothermic reaction of visible light composite resin materials increases with increasing intensity of the light source. A higher intensity light source is more effective in curing the resins than higher temperature generated by the light source. As a variable, the resin itself, rather than the light source, had a more pronounced, effect upon the temperature rise during curing. For those visible light-cured resins that take a long time to reach their peak temperature, a prolonged exposure time is needed to achieve a proper cure.

A comparison using various composite resins and placement techniques is made of the margin quality and isotope microleakage of Class II composite resin restorations placed in extracted molars. Margin quality and isotope microleakage analyses of Class II restorations placed in extracted human molars were compared using various composite resins and placement techniques. At occlusal margins, the traditional (experimental) composite resin restoration placed by the incremental technique showed less microleakage than did the experimental (commercial) composite resin restoration placed by the bulk technique. In each group, the occlusal and proximal adaptations had significantly higher “excellent margin” than did the cervical adaptation. Thus, the marginal adaptation at the cervical aspect of conventional Class II composite resin restorations may present a problem with respect to microleakage.