在骨科與牙科臨床上針對大範圍骨缺損治療時，常使用骨移植材以促進癒合。在市售合成骨移植材 中，由氫氧基磷灰石 (hydroxyapatite, HA) 與 β- 三鈣磷酸鹽 (β-tricalcium phosphate, β-TCP) 組成的雙 相磷酸鈣 (biphasic calcium phosphate, BCP) 生醫陶瓷，為廣泛應用之合成骨移植材，但 HA 具有在 體內吸收時間較長之問題。本研究以低結晶性氫氧基磷灰石 (poor crystalline HA, PC-HA) 與 β-TCP 組成雙相磷酸鈣骨移植材，藉由動物實驗評估比較不同比例移植材在骨缺損中新骨生成速率。本實 驗室以濕式化學沈澱法分別反應生成 PC-HA 與 β-TCP 後，經過濾、混合、乾燥、壓錠、燒結、粉 碎後以不同網目篩網控制顆粒大小，備製磷酸鈣骨移植材 (PC-HA/β-TCP) ，藉由掃描式電子顯微鏡
、傅氏紅外光譜儀與 X 光繞射分析儀進行材料之物化性分析。在動物實驗時，首先對四隻米格魯成 犬拔除所有之小臼齒，等待 16 週癒合期後，對齒槽骨製造直徑 3 mm ，高 6 mm 之圓柱狀人工骨缺 損，同時將三種不同比例之 (PC-HA/β-TCP 70/30, 60/40, and 0/100) 材料植入缺損處為實驗組，以 市售 MBCP®(HA/β-TCP=60/40), Cerasorb®(β-TCP=100%) 與未放置材料組別作為空白對照組。手術 後 8 週在各區取出直徑 5 mm ，高 8 mm 圓柱狀區域進行組織切片觀察。切片結果顯示實驗室材料 與市售商品在牙科骨缺損中，皆具備良好生物相容性，且能促進骨癒合。以 one-way ANOVA 分析 新骨生成率 (ratio of new bone formation) ，結果顯示組別間具有統計上差異 (P<0.05) ，以 Duncan m ultiple range test 分析顯示有置放骨移植材料之各組之新骨生成率皆明顯優於空白對照組，另 PC-HA /β-TCP= 70/30, 60/40 之新骨生長率明顯大於 β-TCP(100%) 。由各組間之信度值 (coefficient of varian ce, CV) ，可發現 PC-HA/β-TCP= 70/30 與 60/40 之新骨生成率較 MBCP® 及 Cerasorb® 商品及空白 對照組之分布均勻，推測較適於新生骨生長。結果顯示 poor crystalline HA/β-TCP 為適合骨缺損使 用之新式雙相磷酸鈣骨移植材。
雙相磷酸鈣人工骨移植材料之體內試驗
Bone substitute materials are widely used to accelerate healing process while suffering large bone defects i n orthopedic and dental clinics. Commercial biphasic calcium phosphate (BCP), containing hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), is a widely used synthetic bone graft with the shortcoming of pr olonged resorption time. In this study, poor crystalline hydroxyapatite (PC-HA) and β-TCP were mixed in different ratios to investigate which mixing ratio could be adapted to the resorption rate of clinical applicati on for dental bony defect. After preparing PC-HA and β-TCP by wet chemical precipitation method separat ely , granular type bone grafts were collected by filtrating, freeze drying, tableting, sintering, mixing, and s ize screening. All the bone graft specimens were analyzed with scanning electric microscope (SEM), Fouri er transform infrared spectrometer (FT-IR) and X-ray diffraction (XRD). Prior to the implantation experim ents, all premolars of 4 beagles were extracted. After 16 weeks of healing period for stabilizing the wound sites in alveolar bone, 8 cylinder type of artificial bony defect (3 mm diameter, 6 mm length) were produce d, and filled with disinfected BCP of (PC-HA/β-TCP= 70/30, 60/40, 0/100) as experimental groups and co mmercial products of MBCP® (HA/β-TCP= 60/40), Cerasorb®(β-TCP=100%), and empty defect as contr ol groups. The cylinder type bone blocks (5 mm diameter, 8 mm length) were brought out at 8 weeks posto peratively for histological studies. There are significant differences of new bone formation ratio between al l experimental and control groups (one-way ANOVA, P < 0.05). The results of Duncan multiple range test also showed significant differences between treatment groups compare to empty control groups, PC-HA/
β-TCP=70/30 to β-TCP, and PC-HA/ β-TCP=60/40 to β-TCP groups. Comparison of the coefficient variati on (CV), the distribution in experimental groups of new bone formation show better evenness than groups of MBCP®, Cerasorb®, and empty controls. The results showed that BCP of experimental groups and com mercial products are biocompatible and the healing effects are better than unfilled empty control groups, in dicating BCP of PC-HA/β-TCP is a new choice for bone defects filling.
