Incorporation of Ca, P, and Si on bioactive coatings produced by plasma electrolytic oxidation: The role of electrolyte concentration and treatment duration.

The objectives of the present study were to produce bioactive coatings in solutions containing Ca, P, and Si by plasma electrolytic oxidation (PEO) on commercially pure titanium, to investigate the influence of different electrolytes concentration and treatment duration on the produced anodic films and to evaluate biocompatibility properties. The anodic films were characterized using scanning electron microscopy, energy-dispersive spectroscopy, atomic force microscopy, and x-ray diffraction and x-ray photoelectron spectroscopies. The surface energy and roughness were also evaluated. PEO process parameters influenced the crystalline structure formation and surface topography of the anodic films. Higher Ca content produced larger porous (volcanolike appearance) and thicker oxide layers when compared to the lower content. Treatment duration did not produce any topography difference. The treatment modified the surface chemistry, producing an enriched oxide layer with bioactive elements in the form of phosphate compounds, which may be responsible for mimicking bone surface. In addition, a rough surface with increased surface energy was generated. Optimal spreading and proliferation of human mesenchymal stem cells was achieved by PEO treatment, demonstrating excellent biocompatibility of the surface. The main finding is that the biofunctionalization with higher Ca/P on Ti-surface can improve surface features, potentially considered as a candidate for dental implants.

Effect of chemical and microwave disinfection on the surface microhardness of acrylic resin denture teeth.

PURPOSE: The purpose of this study was to evaluate the effect of simulated disinfections (2% glutaraldehyde, 1% sodium hypochlorite, and microwave energy) on the surface hardness of Trilux, Biocler, Biotone, New Ace, and Magister commercial artificial teeth. MATERIALS AND METHODS: Specimens (n = 10) were made with the teeth included individually in circular blocks of acrylic resin, leaving the labial surface exposed. Cycles of simulated chemical disinfection were accomplished with the specimens immersed in the solutions at room temperature for 10 minutes, followed by tap water washing for 30 seconds and storage in distilled water at room temperature for 7 days until the next disinfection. Simulated disinfection by microwave energy was carried out in a domestic oven with 1300 W at a potency of 50% for 3 minutes with the specimens individually immersed in 150 ml of distilled water. Control (no disinfection) and the experimental groups (first and third disinfection cycles) were submitted to Knoop hardness measurements with indentations at the center of the labial tooth surface. Data were submitted to repeated measure two-way ANOVA and Tukey's test (α = 0.05). RESULTS: Biocler, Magister, and Trilux showed lower surface microhardness when submitted to microwave. Lower microhardness for Biotone was promoted by hypochlorite, while no significant difference was shown for New Ace. The third disinfection cycle significantly decreased the tooth surface hardness only for microwave. CONCLUSIONS: Different disinfection methods promoted different effects on the microhardness of different types of artificial teeth. Surface microhardness of the teeth was less affected by the simulated chemical disinfections when compared to microwaved specimens.

Effect of aluminium oxide particle sandblasting on the artificial tooth-resin bond.

AIM: The influence of tooth ridge-lap surface sandblasting with aluminium oxide particles was evaluated on the adhesion of artificial teeth to acrylic resins. METHODS: Specimens were made with the acrylic resin adhered to teeth (BioCler GII), according to an unmodified surface, glossy surface sandblasted with 50-µm particles and conventional (Classico) or microwaved (Onda Cryl) resin, and a glossy surface sandblasted with 100-µm particles and Classico or Onda Cryl resin. The shear bond test was performed in an Instron machine using a 500-N load cell and cross-speed of 1 mm/min. RESULTS: The analysis of variance revealed significant difference in the tooth-resin shear bond strength for resin, surface treatment, and interaction. For conventional resin, control, 50-, and 100-µm particles showed statistically-different values; for microwaved resin, the control showed less statistical difference when compared to 50- and 100-µm particle treatments; for between resins, only the 100-µm particle treatment showed statistically-different values, with lower values for the microwaved resin. Mixed failures (cohesive in the resin and adhesive) were predominantly observed in all groups. Mixed (cohesive in the tooth and adhesive) or adhesive failures were not observed. CONCLUSIONS: Sandblasting with different aluminium oxide particle sizes produced different effects on the shear strength values of the tooth-resin bond.