Implant placement in irradiated bone ?Effects of hydroxyapatite after anodic oxidation and hydrothermal treatment

目的：虽然有一些关于骨结合种植体用于颌面修复的报道，但关于辐射对骨/钛界面的影响仍然知之甚少。因为在处理放射治疗后植入物插入骨中的病例时，了解这种关系非常重要。我们报告了骨/钛界面钙化的初级阶段受辐射暴露量的影响。方法：采用直径1-2 mm、长15 mm的锥形纯钛棒进行体内实验，测量其与辐照骨的结合强度。对钛的表面进行机械抛光。日本白色家兔在全身麻醉下，每侧股骨分别照射0.04Gy、0.4Gy、4Gy、40 Gy。24小时后，将三根钛棒插入钻孔中，压配至每个股骨的锥形形状。植入后2周或3周取标本，以0.5mm/mm的十字头速度进行推出试验，然后用扫描电镜和能谱仪观察标本表面（能量色散X射线荧光光谱仪）。4Gy以下的辐照剂量对骨/钛界面结合强度无明显影响，植入3周后40 Gy辐照对骨/钛界面结合强度有影响。钛界面受到辐射暴露量的影响。

Purpose:Although there have been several reports concerning the use of osseointegrated implants for maxillofacial prosthesis, little is still understood about the effects of radiation on the bone/titanium interface. Since it is quite important to know this relationship when dealing with cases where implants have been inserted into the bone after radiotherapy. We reported that the primary stage of calification on the bone/titanium interface was affected upon the amount of radiation exposure. In this study, we use the pure Ti rods in vivo experiment and measured bonding strength to irradiated bone.Method:Tapered pure titanium rods that were 1-2 mm in diameter and 15 mm in length were employed. The surface of titanium was machine polished. Under general anesthesia, approximately 0.04Gy, 0.4Gy, 4Gy, 40Gy was irradiated to each one side femoral of Japanese white rabbits. After 24hours, three titanium rods were inserted into drilled holes press-fitted to a tapered shape in the each femoral. At 2 or 3weeks after insertion, the specimens were harvested, and a push-out test was performed at a crosshead speed of 0.5 mm/mm. Afterwards, the surfaces of the specimens were observed by a SEM and EDX (Energy Dispersive X-ray Fluores cence Spectrometer).Results:Irradiation doses under 4Gy induced no significant changes of the strength between the bone/titanium interfaces.The bone bonding strength were affected upon 40Gy radiation exposure after 3weeks implantation.CONCLUSIONThe bone bonding strength between the bone/titanium interfaces were affected upon the amount of radiation exposure.