Effect of topical administration of Bisphosphponate on bone resorption under denture base

双膦酸盐(BP)S是一种高效的破骨细胞性骨吸收抑制剂。将280只Wistar大鼠随机分为3组(BP(+)组、BP(-)组和Covered组)和1个对照组。实验义齿在不受任何机械压力的情况下覆盖和接触腭部组织。BP(+)和BP(-)组设计义齿基托，在咀嚼过程中对腭部组织施加20kpa的咀嚼压力。BP(+)组在义齿植入前向义齿支持组织内注射BP 5μg，持续2周。BP(-)组注射生理盐水。对照组在整个实验过程中不进行有意治疗。注射荧光骨标记物进行骨组织学观察。义齿植入后1~10周，每隔1周取出腭部组织，用甲基丙烯酸甲酯包埋。采用组织形态计量学方法，对每个腭部第一、第二磨牙区前部50μm厚的组织切片进行组织形态计量学分析，BP(-)组和BP(+)组在1~4周和2周时腐蚀面积分别大于覆盖组。BP(+)组1~3周的腐蚀面明显小于BP(-)组。BP(-)组和BP(+)组的骨吸收量分别为51.8和10.7μm，两组比较差异有统计学意义。因此，局部应用BP减少了义齿基托下的骨吸收，并有效地保存了剩余的牙槽骨。

Bisphosphonate(BP)s are high potent inhibitors of osteoclastic bone resorption. We examined whether topical administration of BP could prevent osteoclastic bone resorption under denture base.Two hundred and eighty Wistar rats were divided into 3 denture wearing groups (BP(+),BP(-) and covered group) and 1 control group. The experimental denture was installed to cover and to contact with the palatal tissue without any mechanical pressure. In the BP(+) and BP(-) groups, the denture base was designed to exert the masticatory pressure of 20 kPa to the palatal tissue in mastication. In the BP(+) group, 5 μg of BP was injected into the denture supporting tissue for 2weeks before denture insertion. BP(-) group was injected into saline solution. For control group, intentional treatment was not received throughout the experimental period. Fluorescent bone labeling was injected for bone histomorphology. The palatal tissues were excised from 1 to 10 weeks after denture insertion at intervals of 1 week and embedded in methyl-methacrylate. The sections, ground frontally at about 50 μm-thickness at first and second molar region of each palatal tissue, were analyzed histomorphometrically using a two-dimensional graphic-analysis system.In the BP(-) and BP(+) groups, eroded surface was larger than the covered group from 1 to 4 weeks and 2 week, respectively. Eroded surface in the BP(+)group was significantly smaller than that in the BP(-) group from 1 to 3 weeks. Amount of bone resorption in the BP(-) and BP(+) groups were 51.8 and 10.7 μm, respectively, and there was a significant difference between these two groups. Therefore, topical administration of BP decreased bone resorption under denture base, and was effective for preservation of residual alveolar ridge.