Histomorphometric evaluation of bone healing with fully interconnected microporous biphasic calcium phosphate ceramics in rabbit calvarial defects / 대한치주과학회지

PURPOSE: The purpose of this study was to histomorphometrically evaluate the osteoconductivity of a new biphasic calcium phosphate ceramics with fully interconnected microporous structure. MATERIAL AND METHODS: Osseous defects created in the rabbit calvaria were filled with four different bone graft substitutes. Experimental sites were filled with a new fully interconnected microporous biphasic calcium phosphate with(BCP-2) or without(BCP-1) internal macropore of 400micrometer in diameter. MBCP(Biomatlante, France) and Bio-Oss(Geistlich Pharma, Switzerland) were used as controls in this study. Histomorphometric evaluation was performed at 4 and 8 weeks after surgery. RESULT: In histologic evaluation, new bone formation and direct bony contact with the graft particles were observed in all four groups. At 4 weeks, BCP-1(15.5%) and BCP-2(15.5%) groups showed greater amount of newly formed mineralized bone area(NB%) compared to BO(11.4%) and MBCP(10.3%) groups. The amounts of NB% at 8 weeks were greater than those of 4 weeks in all four groups, but there was no statistically significant differences in NB% between the groups. CONCLUSION: These results indicate that new bone substitutes, BCP with interconnected microporous structure and with or without internal macroporous structures, have the osteoconductivity comparable to those of commercially available bone substitutes, MBCP and Bio-Oss.

Cellular activities of osteoblast-like cells on alkali-treated titanium surface / 대한치주과학회지

No abstract available.

Comparative study on the physicochemical properties and cytocompatibility of microporous biphasic calcium phosphate ceramics as a bone graft substitute / 대한치주과학회지

OBJECTIVE: The purpose of this study was to evaluate the physicochemical properties and cytocompatibility of microporous, spherical biphasic calcium phosphate(BCP) ceramics with a 60/40 hydroxyapatite/beta-tricalcium phosphate weight ratio for application as a bone graft substitute. MATERIALS AND METHODS: Microporous, spherical BCP granules(MGSB) were prepared and their basic characteristics were compared with commercially available BCP(MBCP; Biomatlante, France) and deproteinized bovine bone mineral(Bio-Oss; Geistlich-Pharma, Switzerland, BBP; Oscotec, Korea). Their physicochemical properties were evaluated by scanning electron microscopy, X-ray diffractometry, Fourier-transform infrared spectroscopy, inductively coupled plasma atomic emission spectrometer, and Brunauer-Emmett-Teller method. Cell viability and proliferation of MC3T3-E1 cells on different graft materials were evaluated. RESULTS: MGSB granules showed a chemical composition and crystallinity similar with those in MBCP, they showed surface structure characteristic of three dimensionally, well-interconnected micropores. The results of MTT assay showed increases in cell viablity with increasing incubation times. At 4d of incubation, MGSB, MBCP and BBP showed similar values in optical density, but Bio-Oss exhibited significantly lower optical density compared to other bone substitutes(p < 0.05). MGSB showed significantly greater cell number compared to other bone substitutes at 3, 5, and 7d of incubation(p < 0.05), which were similar with those in polystyrene culture plates. CONCLUSION: These results indicated the suitable physicochemical properties of MGSB granules for application as an effective bone graft substitute, which provided compatible environment for osteoblast cell growth. However, further detailed studies are needed to confirm its biological effects on bone formation in vivo.

The effects of heat treatment on the mechanical properties of the elgiloy wire / 대한치과교정학회지

Heat treatment which removes internal stress enhances the mechanical properties of the orthodontic arch wire. The main purpose of this experiment was to investigate the effects of the heat treatment on the mechanical properties of the Elgiloy wire. The Elgiloy wire, 0.016" X 0.022" and 0.018" X 0.025", were heat treated in an electric oven for 5, 10 and 15 minutes at selected temperatures between 300 and 900degreesC. Tensile strength and load deflection rate were measured to reveal the changes of mechanical property at various con?ditions, and each specimen was observed under metallurgic microscope. Also to trace the precipitation material due to overheat treatment, a qualitative analysis was carried out with EDS system. It was found that heat treatment at a low temperature caused an increase in the tensile strength and bending resistance, and a maintenance in the fibrous in the tensile strength and bending resistance, and a maintenance in the fibrous structure of both sizes of wire. The changes observed in properties and appearance were probably due to the relief of internal stresses incurred in the metal during cold working. In both sizes of wire the tensile strength and the bending resistance continued to decrease at high temperature, and the fibrous structure continued to disappear then was not observed at 900degreesC. The carbide precipitation founded in grain boundary at 750degreesC probably was other elements carbide (Ni, Co) except Cr. The grain growth was observed at 1100degreesC. Optimum heat treatment for the 0.016" X 0.022" Elgiloy wire was 10 minutes at 500degreesC, and for the 0.018" X 0.025" Elgiloy wire it was 5 to 15 minutes at 500degreesC.