Demineralized bone matrix and calcium-phosphate cement in bone regeneration in rats

Abstract Purpose: To compare bone regeneration in critical-sized defects in rat calvarium using demineralized bone matrix and calcium phosphate cement. Methods: Thirty Wistar rats were divided into 3 groups of 10 animals each. Two defects of 5-mm were made in the parietal bones of each animal. Group I had calcium phosphate cement placed in the experimental defect, Group II had filled with demineralized bone matrix and Group III had with the combination of the matrix and cement in equal parts. All animals had one defect left unfilled to serve as controls. Five animals in each group were sacrificed at 4 and 8 weeks. Histomorphometric analysis was used to quantify the amount of new bone within the defects. Results: The results showed that demineralized bone matrix-treated defects had significantly more new bone at 4 weeks compared to calcium phosphate cement-treated defects (p=0.03) and also had significantly more new bone at 8 weeks compared to unfilled defects (p=0.04). Conclusions: The demineralized bone matrix was superior to calcium phosphate cement in bone regeneration. It seems that calcium phosphate cement acted by inhibiting the osteogenesis when associated with a demineralized bone matrix and this combination should not be recommended.

Abstract
目的：比较脱钙骨基质（demineralized bone matrix）与磷酸钙骨水泥（calcium phosphate cement）修复大鼠颅骨临界尺寸骨缺损的骨再生效果。
方法：将30只Wistar大鼠分为3组，每组10只。于每只大鼠的顶骨制备2个5mm直径的临界尺寸骨缺损。第I组于实验缺损处植入磷酸钙骨水泥，第II组植入脱钙骨基质，第III组植入等比例混合的脱钙骨基质与磷酸钙骨水泥。所有大鼠均保留1个缺损不予填充作为空白对照。每组分别于术后4周、8周处死5只大鼠，采用组织形态计量法定量分析缺损区域内新生骨的含量。
结果：术后4周时，脱钙骨基质处理组的缺损区域新生骨量显著高于磷酸钙骨水泥处理组（p=0.03）；术后8周时，脱钙骨基质处理组的新生骨量亦显著高于空白对照组（p=0.04）。
结论：脱钙骨基质的骨再生效果优于磷酸钙骨水泥。当二者联合使用时，磷酸钙骨水泥会抑制成骨（osteogenesis）过程，因此不推荐该联合治疗方案。