• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권4호
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• pp.468-474
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• 2008

Purpose: Previous clinical investigations of sinus floor augmentation have demonstrated repneumatization of grafted sinus. The aim of this study is to evaluate and compare the height changes of sinus floor after grafting with deprotenized bovine bone mineral (DBBM) and beta tricalcium phosphate (TCP). Materials and methods: 34 sinuses in 28 patients were augmented with 100% DBBM or 100% TCP through lateral approaches. Sinusgraft height was measured before, immediately after, and 6 months after bone graft with panoramic radiography. Result: After 6 months, the decreases of graft heights were 14.53% for DBBM group and 15.15% for TCP group. There was no statistically significant difference. Discussion and Conclusion: Long-term stability of sinus-graft height represents an important factor for implant success. After the uses of DBBM and TCP for maxillary sinus floor augmentations, acceptable graft height maintenances were observed.

• Journal of Periodontal and Implant Science
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• 제32권3호
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• pp.489-500
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• 2002

The purpose of this study was to evaluate newly fabricated tricalcium phosphate(TCP)/chitosan microgranuls as bone substitutes. TCP/chitosan microgranules were fabricated by dropping TCP-chitosan suspension into the NaOH/ethanol solution. The size of microgranules could be controllable via airflow rate. PDGF-BB was loaded into the fabricated granules via freeze-drying methods(300 ng/20 mg). To evaluate cell proliferation, cultured osteoblasts cell lines(MC3T3-El) was dropped on the BioOss(R), chitosan microgranules, TCP/chitosan microgranules and cultured for 1, 7 , 14, and 28 days. Scanning electron microscopic observation was done after 7 days of culture and light microscopic examination was done after 28 days of culture. PDGF-BB release from the microgranules was tested. Rabbit calvarial defects(8 mm in diameter) were formed and chitosan, TCP/chitosan, PDGF-TCP/chitosan microgranules, and BioGran(R) were grafted to test the ability of new bone formation. At SEM view, the size of prepared microgranules was 250-1000 um and TCP powders were observed at the surface of TCP/chitosan microgranules. TCP powders gave roughness to the granules and this might help the attachment of osteoblasts. The pores formed between microgranules might be able to allow new bone ingrowth and vascularization. There were no significant differences in cell number among BioOss(R) and two microgranules at 28 day. Light and scanning electron microscopic examination showed that seeded osteoblastic cells were well attached to TCP/chitosan microgranules and proliferated in a multi-layer. PDGF-BB released from TCP/chitosan microgranules was at therapeutic concentration for at least 1 week. In rabbit calvarial defect models, PDGF-TCP/chitosan microgranules grafted sites showed thicker bone trabeculae pattern and faster bone maturation than others. These results suggested that the TCP/chitosan microgranules showed the potential as bone substitutes.

• 한국결정성장학회지
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• 제32권3호
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• pp.96-102
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• 2022

수산화칼슘(Ca(OH)₂)과 인산(H₃PO₄) 수용액을 반응시켜 수산화아파타이트(hydroxyapatite, HAp)를 합성하였다. 3 M 이상의 고농도 수산화칼슘원료를 전구체로 사용하고 인산 첨가속도, 반응용액 유지시간, 반응생성물에 대한 볼밀링, 합성 후 열처리 같은 합성조건을 변화시켜 HAp를 합성하였다. 인산 첨가속도에 관계없이 상온에서 합성할 경우 주된 불순물상(phase)인 DCPD(dicalcium phosphate dihydrate)가 형성되었고, 700℃ 이상 가열 시 β-TCP(tricalcium phosphate)가 합성되기 시작해 900℃에서 그 양이 최대가 되었다. 합성된 분말을 1150℃에서 소결 할 경우에도 고온안정 불순물 상인 β-TCP 상은 없어지지 않고 남아있었다. 합성 수용액에 대한 볼밀링 후 3일 간 그 용액을 유지할 경우 DCPD 상이 없는 단일 HAp 상을 얻을 수 있었으며, 유지시간 없이 합성물에 대한 볼밀링 과정만을 거친 경우에도 500℃ 이상 열처리를 통해 β-TCP 상이 없는 단일상의 HAp를 얻을 수 있었다. 이러한 추가적인 볼밀링 과정을 적용함으로써 HAp를 손쉽게 합성할 수 있었다.

• 한국세라믹학회지
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• 제40권8호
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• pp.730-734
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• 2003

This research examined the effect, which it follows in particle size distribution change of CaHPO$_4$ㆍ2$H_{2}O$ (DCPD). We used two kinds of compositions; tetracalcium phosphate (TTCP)/dicalcium phosphate dihydrate (DCPD) composition and $\alpha$-tricalcium phosphate ($\alpha$-TCP)TTCP/DCPD composition. As the result, the mean particle size of the DCPD decreased, the setting tine shortened at all compositions. The reference powder (DR), which did not milling, showed about 2 times strength value compared with other milling sample. Especially, the compressive strength of 60 : 20 : 20 sample (DR(do$_{0.5}$)=12.08 $\mu\textrm{m}$) after curing 7 days in simulated body fluid solution was 40$\pm$0.5 MPa, which was the highest. This resulted from the packing density at $\alpha$-TCP/TTCP/DCPD combination.

• 한국재료학회지
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• 제16권1호
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• pp.1-4
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• 2006

Biodegradable $\beta$-tricalcium phosphate ( $\beta$-TCP)/poly(lactide-co-glycolide) (PLGA) composites were synthesized by in-situ polymerization with microwave energy. The influence of the $\beta$-TCP content in $\beta$-TCP/PLGA composites on the molecular weight, crystallinity, microstructure and mechanical properties was investigated. As the molecular weight of composites decreased, the $\beta$-TCP content increased up to 10 wt.%, while the excess addition of the $\beta$-TCP content above 10 wt.% the molecular weight increased with increasing of the $\beta$-TCP content. This behavior would be due to the superheating effect or nonthermal effect induced by microwave energy. It was found that the bending strength and Young's modulus of the $\beta$-TCP/PLGA composites was proportional to the molecular weight of PLGA. The bending strength of the $\beta$-TCP/PLGA composites ranged from 18 to 38 MPa, while Young's modulus was in the range from 2 to 6 GPa.

• 방사선산업학회지
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• 제3권1호
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• pp.39-45
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• 2009

Three mineral phosphate solubilizing (MPS) bacteria where isolated from rhizosphere soil samples of common bean and weed plants. 16S rDNA analysis indicated that the isolate P2 and P3 are closely related to Pantoea dispersa while isolate P4 is closely related to Pantoea terrae. Isolates P2 and P3 recorded $381.60{\mu}g\;ml^{-1}$ and $356.27{\mu}g\;ml^{-1}$ of tricalcium phosphate (TCP) solubilization respectively on 3 days incubation. Isolate P4 recorded the TCP solubilization of $215.85{\mu}g\;ml^{-1}$ and the pH was dropped to 4.44 on 24 h incubation. Further incubation of P4 sharply decreased the available phosphorous to $28.94{\mu}g\;ml^{-1}$ and pH level was raised to 6.32. Gamma radiation induced mutagenesis was carried out at $LD_{99}$ dose of the wild type strains. The total of 14 mutant clones with enhanced MPS activity and 4 clones with decreased activity were selected based on solubilization index (SI) and phosphate solubilization assay. Mutant P2-M1 recorded the highest P-solubilizing potential among any other wild or mutant clones by releasing $504.21{\mu}g\;ml^{-1}$ of phosphorous i.e. 35% higher than its wild type by the end of day 5. A comparative evaluation of TCP solubilization by wild type isolates of Pantoea and their mutants, led to select three MPS mutant clones such as P2-M1, P3-M2 and P3-M4 with a potential to release >$471.67{\mu}g\;ml^{-1}$ of phosphorous from TCP. These over expressing mutant clones are considered as suitable candidates for biofertilization.

• 한국재료학회지
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• 제29권2호
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• pp.129-135
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• 2019

A powder mixture of 70 wt% $Al_2O_3$ and 30 wt% hydroxyapatite (HA) is sintered at $1300^{\circ}C$ or $1350^{\circ}C$ for 2 h at normal pressure. An $MgF_2$-added composition to make HA into fluorapatite (FA) is also prepared for comparison. The samples without $MgF_2$ show ${\alpha}$ & ${\beta}$-tricalcium phosphates (TCPs) and $Al_2O_3$ phases with no HA at either of the sintering temperatures. In the case of $1,350^{\circ}C$, a $CaAl_4O_7$ phase is also found. Densification values are 69 and 78 %, and strengths are 156 and 104 MPa for 1,300 and $1,350^{\circ}C$, respectively. Because the decomposition of HA produces a $H_2O$ vapor, fewer large pores of $5-6{\mu}m$ form at $1,300^{\circ}C$. The $MgF_2$-added samples show FA and $Al_2O_3$ phases with no TCP. Densification values are 79 and 87 %, and strengths are 104 and 143 MPa for 1,300 and $1,350^{\circ}C$, respectively. No large pores are observed, and the grain size of FA ($1-2{\mu}m$) is bigger than that of TCP ($0.7{\mu}m{\geq}$) in the samples without $MgF_2$. The resulting $TCP/Al_2O_3$ and $FA/Al_2O_3$ composites fabricated in situ exhibit strengths 6-10 times higher than monolithic TCP and HA.

• 한국세라믹학회지
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• 제33권1호
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• pp.7-16
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• 1996

${CO_3}^{2-}$ containing whisker-like hydroxyapatite powders were synthesized byhomogeneous precipitation method using urea, Dicalcium phosphate anhdrate[DCPA; $CaHPO_4$] and octacalcium phosphate [OCP; $Ca_8H_2(PO_4_)6\cdot5H_20$]were obtained as precursors and they transformed to high crystalline hydroxyapatites at pH 5.62, and 6.54 respectively. According to the condition of the final pH in the solutions for the solution products and urea contents OCP was remained. When the solution product of $Ca^{2-}$ and ${PO_4}^{3-}$ was $1.5\times 10^4$[$mM^2$] and the content of urea was 0.25 mol.$dm^{-3}$ well crystallized whisker-like hydroxyapatite tens of micrometer in length was obtained. By heat treatment DCPA and OCP were decomposed into $\beta$-tricalcium phosphate [$\beta$-TCP ; $\beta$-$Ca_3{PO_4}_2$] and $\beta$-dicalcium phosphate [$\beta$-DCP ;$\beta$-$Ca_2P_2O_4}_2$]. And well-crystallized hydroxyapatite was partially decomposed into $\beta$-TCP at $800^{\circ}C$.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권1호
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• pp.36-48
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• 2008

To repair bone defects in the oral and maxillofacial field, bone grafts including autografts, allografts, and artificial bone are used in clinical dentistry despite several disadvantages. The purpose of this study was to evaluate new bone formation and healing in rat calvarial bone defects using hydroxyapatite (HA, $Ca_{10}[PO_4]_6[OH]_2,\;Bongros^{(R)}$, Bio@ Co., KOREA) and tricalcium phosphate (${\beta}-TCP,\;Ca_3[PO_4]_2$, Sigma-Aldrich Co., USA) mixed at various ratios. Additionally, this study evaluated the effects of type I collagen (Rat tail, BD Biosciences Co., Sweden) as a basement membrane organic matrix. A total of twenty, 8-week-old, male Sprague-Dawley rats, weighing 250-300g, were divided equally into a control group (n=2) and nine experimental groups (n=2, each). Bilateral, standardized transosseous circular calvarial defects, 5.0 mm in diameter, were created. In each experimental group, the defect was filled with HA and TCP at a ratio of 100:0, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, and 0:100 with or without type I collagen. Rats were sacrificed 4 and 8 weeks post-operation for radiographic (standardized plain film, Kodak Co., USA), histomorphologic (H&E [Hematoxylin and Eosin], MT [Masson Trichrome]), immunohistochemical staining (for BMP-2, -4, VEGF, and vWF), and elementary analysis (Atomic absorption spectrophotometer, Perkin Elmer AAnalyst $100^{(R)}$). As the HA proportion increased, denser radiopacity was seen in most groups at 4 and 8 weeks. In general radiopacity in type I collagen groups was greater than the non-collagen groups, especially in the 100% HA group at 8 weeks. No new bone formation was seen in calvarial defects in any group at 4 weeks. Bridging bone formation from the defect margin was marked at 8 weeks in most type I collagen groups. Although immunohistochemical findings with BMP-2, -4, and VEGF were not significantly different, marked vWF immunoreactivity was present. vWF staining was especially strong in endothelial cells in newly formed bone margins in the 100:0, 80:20, and 70:30 ratio type I collagen groups at 8 weeks. The calcium compositions from the elementary analysis were not statistically significant. Many types of artificial bone have been used as bone graft materials, but most of them can only be applied as an inorganic material. This study confirmed improved bony regeneration by adding organic type I collagen to inorganic HA and TCP mixtures. Therefore, these new artificial bone graft materials, which are under strict storage and distribution systems, will be suggested to be available to clinical dentistry demands.

• 생명과학회지
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• 제24권6호
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• pp.642-647
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• 2014

치아과민증은 치아의 병적인 증세는 아니지만 치아뿌리가 잇몸밖으로 노출되어 외부의 자극에 대한 민감한 반응으로 환자가 통증을 느끼는 것을 말한다. 칫솔질이나 잇몸질환 등의 다양한 원인이 있으며 치료를 위해서는 자극을 줄여 주는 방법으로 치아과민치료활성이 있는 물질을 이용하거나 레진으로 들어난 치주를 도포하는 방법이 있다. 본 연구에서 수산화인회석과 인산삼칼슘을 혼합하여 만든 치약과 시중에 판매하고 있는 불소함유치약을 4주간 사용하면서 치주과민성 치료효과를 비교 조사하였다. 첨가한 수산화인회석과 인산삼칼슘의 순도는 XRD분석결과 99% 이상으로 나타났으며, 제조한 치약(Hap-TCP)에는 각각 10%와 19%(W/W) 되게 첨가하였다. 치아과민성 치료효과를 VRS값으로 조사한 결과 사용직후에는 대조군과 차이가 없었으나, 1주후에는 대조군에 비해 8% 통증감소효과가 나타났고, 2주와 4주 후에는 각각 30%와 60%정도 통증감소효과가 나타났다. 그리고 냉자극에 대한 지각과민증을 VAS값으로 조사한 결과도 초기에는 차이가 없었으나, 1주, 2주, 4주 후에 측정한 결과 기간에 따라 유의적으로 감소하였다. 4주후에는 VAS값이 3배이상 차이를 보였다. 이 결과는 현미경관찰에서도 확인이 되어진 것과 같이 수산화인회석이 확장된 상아세관들을 메우고, 구강내의 칼슘, 인 등 이온평형을 인산삼칼슘이 조절하여 메워진 상아세관을 안정적으로 자리를 잡도록 도와주는 재석회화현상으로 치아과민증상을 완화하는 것으로 확인되었다.