Effect of surface treatments of porcelain on adhesion of Candida albicans.

Surface treatment of porcelain is required to minimize the adhesion of microorganisms to surfaces of the restoration. This study sought to assess the effects of 3 different porcelain surface treatments on adhesion of Candida albicans. This in vitro experimental study was conducted on 60 porcelain disks (10 × 3 mm) randomly divided into 4 groups of 15. The nonglazed group received no surface treatment; specimens in the other 3 groups were glazed in the furnace, overglazed with liquid glaze, or polished using a polishing kit. The specimens were washed, sterilized, and separately incubated with 350 µL of Candida albicans suspension for 24 hours. Specimens were then rinsed for 20 seconds and shaken in 1 mL of saline solution for 1 minute, and 20 µL of this suspension was cultured in a plate and incubated at 37°C for 48 hours. Candida albicans colonies were counted to assess the number of microorganisms adhering to each disk. Data were analyzed with the Kruskal-Wallis test. Statistically significant differences were found among the 4 groups in terms of C albicans adherence (P = 0.001). The nonglazed porcelain had the highest and the overglazed porcelain had the lowest mean adherence value. No statistically significant difference was noted between glazed and polished specimens. Based on the obtained results, overglazing resulted in the least adhesion of C albicans, and polishing provided a surface as smooth as a glazed surface.

Hyalinizing cholecystitis with features of immunoglobulin G4-related disease-coincidence or an unrecognized association? A case report.

Hyalinizing cholecystitis (HC) is a recently described rare subtype of chronic cholecystitis characterized by dense, paucicellular collagenous transmural fibrosis, which usually replaces the mucosa and muscularis propria. Immunoglobulin (Ig)G4-associated cholecystitis is also a newly described cholecystitis variant characterized by transmural or extramural lymphoplasmacytic inflammation, lymphoid follicles, storiform fibrosis, phlebitis, and increased tissue IgG4-positive plasma cells. We describe a case of cholecystitis in an elderly white man who harbored features of both HC and IgG4-associated cholecystitis. In retrospect, the patient also had a significantly elevated serum IgG4 level. To the best of our knowledge, an association between HC and IgG4-related disease has not been previously described in the literature. Although not entirely conclusive, our observations raise the possibility that some cases of HC represent the end stage of IgG4-related disease.

Bioactivity of EndoSequence root repair material and bioaggregate.

AIM: To evaluate the bioactivity of Bioaggregate (BA), EndoSequence Root Repair Material (ERRM), and white ProRoot Mineral trioxide aggregate (MTA). METHODOLOGY: Sixty horizontal root sections with standardized canal spaces were divided randomly into 3 groups (n = 20) and filled with white ProRoot MTA (groups 1 and 2), BA (groups 3 and 4) or ERRM putty (groups 5 and 6). The specimens of groups 1, 3 and 5 (each of 10) were immersed in phosphate-buffered saline (PBS) for 1 week and those of groups 2, 4 and 6 (each of 10) for 2 months. After the experimental periods, the specimens were processed for scanning electron microscopy (SEM) observations. Precipitation of apatite crystals on the surfaces of the cements and/or at the dentine-cement interface was evaluated and analysed elementally by energy dispersive X-ray (EDX) instrument. RESULTS: Analysis of specimens revealed various surface morphologies that were dependent on the material and immersion time in PBS. The formation of precipitates was observed on the surfaces of all materials at 1 week, which increased substantially over time. After 2 months, the surface of the cements was changed dramatically and consisted of a substantially greater amount of apatite aggregates. Interfacial layers in some areas of the dentine-cement interface were found only following 2 months of immersion. Precipitates on MTA revealed high peaks of Ca, Si and O after 1 week of immersion; after 2 months, high peaks of Ca, P and O were present. Precipitates on BA and ERRM displayed high Ca, P O peaks after both 1 week and 2 months. CONCLUSION: Exposure of MTA, BA and ERRM to PBS resulted in precipitation of apatite crystalline structures that increased over time. This suggests that the tested materials are bioactive.

Albizia procera gum as an excipient for oral controlled release matrix tablet.

The purpose of this research was to develop and evaluate controlled release matrix tablets of paracetamol based on natural gum exudates of Albizia procera. Procera gum was characterized of its properties like compressibility index, angle of repose, viscosity and moisture content. The interaction between the gum and paracetamol was also studied through differential scanning calorimetry (DSC) and FTIR spectroscopy. Matrix tablets were then prepared by wet granulation method with different concentrations of procera gum and hydroxypropyl methylcellulose (HPMC) and evaluated for their physical properties like weight variation, hardness, friability and content uniformity. Dissolution study was conducted to characterize release mechanism from the matrix system and data were fitted to various kinetic models. The mechanism of drug release from both types of matrix tablets was found to be anomalous type. Results from various evaluations suggested that A. procera gum could be used as drug release retardant in controlled release matrix systems.

Early healing of nanothickness bioceramic coatings on dental implants. An experimental study in dogs.

Thick bioceramic coatings like plasma sprayed hydroxyapatite have been shown to increase the overall tissue response and biomechanical fixation of dental implants. However, the presence and potential fracture of a bone-coating-metallic substrate interface at long times after implantation led these implants to fall from favor in clinical practice. The purpose of this study was to evaluate the biomechanical fixation and biological response of Ca- and P-based, 20-50 nm thickness bioceramic deposition on a previously alumina-blasted/acid-etched Ti-6Al-4V implant surface in a dog model. Cylindrical alumina-blasted/acid-etched (AB/AE) (Control, n = 16), and Nanothickness bioceramic coated AB/AE(Nano, n = 16) implant surfaces were surgically placed in dogs proximal tibia and remained for 2 and 4 weeks in vivo. Following euthanization, the implants-in-bone were mounted in epoxy and pullout at a 0.5 mm/min rate. Following mechanical testing, the specimens were decalcified and processed (Hematoxylin and Eosin) for standard transmitted light microscopy evaluation. Percent bone-to-implant contact (BIC) to the pulled out implant surface was determined through computer software. Statistical analyses were performed by one-way ANOVA at 95% level of significance and Tukey's post-hoc multiple comparisons. No significant differences in pullout force were observed (p > 0.88): 2W Control (212.08 +/- 42.96 N), 2W Nano (224.35 +/- 42.97 N), 4W Control (207.07 +/- 42.97 N), and 4W Nano (190.15 +/- 45.94 N). No significant differences in %BIC were observed (p > 0.94): 2W Control (72.66 +/- 8.51), 2W Nano (69.44 +/- 8.51), 4W Control (70.44 +/- 8.51), and 4W Nano (69.11 +/- 9.09). It is shown that 20-50 nm thickness bioceramic depositions onto previously alumina-blasted/acid-etched substrates did not improve the biomechanical fixation and the BIC at early implantation times, and studies concerning shorter and longer implantation times are recommended for confirmation or before a conclusion can be made.

[In vitro studies about the effects of implanted materials on osteocalcin and alkaline phosphatase of rat osteoblasts].

OBJECTIVE: To evaluate the effects of the four implant materials, hydroxyl poly calcium sodium phosphate (HPA), hydroxyapatite (HA), bioglass ceramics (BGC) and titanium (Ti) on osteocalcin secreting amount and alkaline phosphatase activity of rat osteoblasts cultured in vitro, and expose the biological compatibility conditions of the implant materials as well as the index to estimate cytocompatibility. METHODS: The powders of HPA, HA, BGC and Ti were sterilized and made into extracted solutions with 199 culture medium, and the isolated osteoblasts which were taken from three-day-old Sprague-Dawley rats' calvaria, were incubated in 199 culture medium too. Then the osteoblasts were mixed and incubated into the four kinds of extracted solutions of the implant materials. After eight days of co-incubation, the cells were taken out to measure alkaline phosphatase activity with velocity analysis, and the extracellular liquid was used to estimate osteocalcin secreting amount with radioisotope analysis. RESULTS: 1. Osteocalcin secreting amount of the osteoblasts co-incubated with HPA, HA, BGC were as normal as the control, while that of other cells co-incubated with titanium was reduced (P < 0.05). 2. Alkaline phosphatase activities of all the co-incubated osteoblasts were as normal as the control. CONCLUSION: The osteocalcin secreting amount and alkaline phosphatase activity can reflect the biological compatibility of implant materials, and they may be used as indexes to evaluate biological compatibility condition of implant materials.

Benign response to particles of diamond and SiC: bone chamber studies of new joint replacement coating materials in rabbits.

Wear particles from total joint replacements are thought to accelerate prosthetic loosening. Diamond coating may improve the smoothness and wear characteristics of the femoral head component of total hip replacements, and thus increase their longevity. The brittleness of a thin diamond coat may be overcome by using an SiC-whisker diamond composite. This study describes the reactions of regenerating bone tissue to phagocytosable particles of diamond and SiC, using implanted bone harvest chambers in rabbits. The particles were dispersed in hyaluronan and introduced into a canal transversing the implant. The tissue that entered the canal during the following 3 weeks was then harvested. In previous studies using this model, particles of high density polyethylene, bone cement and chromium-cobalt all caused an inflammatory reaction and a marked decrease in the amount of ingrown bone. In the present study, neither the diamond nor the SiC particles caused any decrease in bone formation. It appears that particles of diamond and SiC are comparatively harmless.