低钙对微种植体骨结合影响的实验研究

目的 通过建立低钙动物模型来研究低钙状态对微种植体骨结合的影响.方法 将24只实验用健康哈白兔随机分为实验组和对照组,每组12只.实验组定量低钙饲料饲养,对照组正常饲料饲养,定期测量血清钙、镁、磷含量及骨密度值,当实验组骨密度值低于对照组后,进行统计学分析,差异有显著性,有统计学意义,即为低钙模型建立成功,即可进行微种植体的植入.植入后再分别将实验组和对照组随机分为A组：即刻加力组、B组：6周后加力组、C组：8周后加力组及D组：10周后加力组,以镍钛弹簧施力1.47N,于施力当天拍摄X线片,力值持续4周后进行标本制备、扫描电镜下观察.结果 实验组A组6枚种植体全部松动、脱落,种植失败;其余各组种植体在植入和施力后稳定性均良好,扫描电镜显示,对照组4组、实验组B、C、D三组均形成骨结合,且结合程度随时间的延长逐渐增强.结论 低钙实验组在微种植体植入后不可进行即刻加力,需等待＂二期负载＂,且随着＂无负载愈合期＂的延长,其骨结合程度增强,稳定性增强.

Effect of the low calcium on ossteointegration

Objective To investigate the effect of low calcium state on micro implant ossteointegration. Methods Twenty-four healthy experimental rabbits were randomly divided into experimental group and control group (12 rabbits in each group). The rabbits in experimental group were fed with quantitative calcium fodder and the animals in control group with normal diet. Regular measurement of serum calcium, magnesium, phosphorus content and BMD were carried out. When BMD of the experimental group was significantly lower than that of the control group, the microimplant was inserted. The experimental group and control group were randomly divided into subgroup A: immediate force application, subgroup B: force application after 6 weeks, subgroup C: force application after 8 weeks and subgroup D: force application after 10 weeks. The force applied was 1.47N. X-ray film was taken on the day of activation and the force value was maintained for 4 weeks.Then the animals were killed and the specimen preparation and scanning electron microscopy examination were carried out. Results In the subgroup A, six implants became loose or fell off.However, the implants in other subgroups were stable. Scanning electron microscopy examination showed that the ossteo-integration was found in control group, experimental groups B, C and D.Conclusions Immediate force application in low calcium group should be avoided. "healing period"was needed and the ossteo-integration was enhanced.