Acrylic-based denture materials have several common weak points, such as shrinkage after curing, lack of strength and toxicity. In order to solve these problems, we adapted a hybrid system using acrylic polymer and polyhedraloligosilsesquioxane (POSS). The aim of the study was to investigate the biocompatibility of a reinforced acrylic-based hybrid denture composite resin with POSS. Specimens of a novel polymeric denture base resin, in which POSS was used to partially replace the commonly used base monomer, were fabricated. In order to examine changes in biocompatibility with time, fresh specimens, along with specimens soaked in distilled water for 24 and 72 h were fabricated. Three other types of acrylic denture base resins were used to prepare the resin specimens. Biocompatibility (as measured by a metabolic assay, an agar overlay test, and a mutagenesis assay) of the composites was tested. The metabolic and mutagenesis assays were conducted with pure culture medium as a control. In this study, the reinforced acrylic-based hybrid denture composite resin with POSS showed improved biocompatibility and lower mutagenicity than the control. Statistical examinations showed the cell metabolic activity of the novel polymeric denture base resin in the 72-h immersion case as having almost the same inclination as the control. We hope that these results might aid in the development of a reinforced acrylic-based denture resin.

The oxide layer that covers a titanium surface is extremely stable and appears to have excellent biocompatibility, which can result in successful osseointegration. The aim of this study was to analyse the characteristics of an oxide layer formed by anodic oxidation (anodization), and to evaluate the extent of bone healing around the anodized implant. The screw-type implants were made of commercially pure titanium (Grade 2). The Group 1 samples had a turned surface, and three other types of experimental specimens were anodized under constant voltages of 190 V (Group 2), 230 V (Group 3) and 270 V (Group 4). The surface characteristics of each sample type were inspected. Removal torque was measured after a 4-week healing period and the histomorphometric analysis was performed 6 weeks after implantation in rabbit tibiae. There was an increase in both the size and number of pores as the anodizing voltage increased. The Ra value of the Group 4 samples was higher than those in the Group 1 and 2 samples (P < 0.05). Group 3 showed a difference compared with Group 1 (P < 0.05). A thicker oxide layer, which contained crystalline (anatase) TiO(2) with the inclusion of some electrolytes (Ca, P), was formed at the higher anodizing voltage. Group 4 had higher removal torque values and percentages of bone-to-implant contact than the other groups (P < 0.05). The anodized titanium implants showed more intimate and stronger connections with peri-implant bone during early osseointegration than the turned titanium implants in this experimental model.

The oxide layer of a titanium surface is very stable, and seems to result in excellent biocompatibility and successful osseointegration. The purpose of this study was to investigate the effects of high anodic oxidation voltages on the surface characteristics of titanium implants and the biologic response of rabbit tibiae. Bone tissue responses were evaluated by removal torque tests and histomorphometric analysis. Screw-shaped implants with microthreads were made of commercially pure titanium (Grade II). We prepared anodized implants under 300 V (group I), 400 V (group II), 500 V (group III) and 550 V (group IV). The surface characteristics of specimens were inspected according to three categories: surface morphology, surface roughness and oxide layer thickness. The screw-shaped implants were installed in rabbit tibiae. The removal torque values were measured and histomorphometric analysis was done after 1- and 3-month healing periods. Data indicate that as anodic oxidation voltage increased above 300 V, oxide layer thickness increased rapidly and pore size also increased. The roughness values of the implants increased with voltage up to 500 V, but decreased at 550 V. In the removal torque test, group III showed higher values than groups I and II at a statistically significant level (P < 0.05) after a 1-month healing period. In histomorphometric analysis, groups III and IV, after a 3-month healing period, showed greater bone to implant contact ratios for the total implant surface than did group I (P < 0.05).