College of Stomatology, Hebei United University, Tangshan City 063000, China.
Bone. 2012 Jan;50(1):119-27. doi: 10.1016/j.bone.2011.10.011. Epub 2011 Oct 17.
One main problem associated with alveolar bone augmentation in implant dentistry is resorption of grafted bone, which may be further compromised by systemic skeletal disorders such as osteoporosis. Zoledronate acid (ZOL) is the most potent bisphosphonate to treat osteoporosis and therefore it is hypothesized to be able to invert the negative effect of osteoporosis on osseointegration and fixation of dental implants in autologous bone grafts. In this study, 56 rabbits received bilateral ovariectomy (OVX) (40 rabbits) or sham operation (16 rabbits). Three months later, 8 animals from each group were sacrificed for bone mineral density (BMD) examination. Then the remaining animals underwent bilateral autologous iliac bone grafting with simultaneous implantation of titanium implants in tibiae and were divided into 5 groups (n=8): Sham, OVX, Loc-ZOL (local treatment), Sys-ZOL (systemic treatment) and Loc+Sys-ZOL (local plus systemic) group. At 3 months after implantation, all animals were sacrificed and specimens were harvested for examinations. Both BMD and histological examinations of femurs showed osteoporotic changes after ovariectomy, while systemic treatment with ZOL restored mineralized bone. Micro-CT examination demonstrated that OVX group showed significant decrease of mineralized bone and implant-bone contact when compared with sham control, whereas both systemic and local treatments of ZOL significantly increased mineralized bone and implant-bone contact in ovariectomized animals. However, the best effects were observed in Loc+Sys-ZOL group (combined use of ZOL) and most of bone indices were similar to (IBCR, p>0.05) or higher than (BV/TV, Conn.D and Tb.N) (p<0.01) those of the sham group, except Tb.Th, which was still significantly lower (p<0.01), and Tb.Sp, which was further decreased (p<0.01). The aforementioned effects were also confirmed by histomorphometric analysis of bone indices on implant-bone contact and mineralized bone. In addition, biomechanical testing further supported the beneficial effect of ZOL treatment and maximal removal torque of titanium implants was observed in Loc+Sys-ZOL group. In conclusion, our study suggests that both systemic and local treatments with ZOL can invert negative effect of osteoporosis and promote osseointegration and fixation of dental implants in autologous bone grafts under osteoporotic condition. Combined systemic and local use of ZOL exerts best effects when compared to their single use.
在种植体牙科中，与牙槽骨增强相关的一个主要问题是移植物骨的吸收，而骨质疏松等系统性骨骼疾病可能会进一步损害移植物骨的吸收。唑来膦酸（ZOL）是治疗骨质疏松症最有效的双膦酸盐，因此假设它能够逆转骨质疏松症对骨整合和牙种植体在自体骨移植物中的固定的负面影响。在这项研究中，56 只兔子接受了双侧卵巢切除术（OVX）（40 只兔子）或假手术（16 只兔子）。每组的 3 个月后，有 8 只动物被处死进行骨密度（BMD）检查。然后，其余动物接受双侧自体髂骨移植，并同时在胫骨中植入钛植入物，并分为 5 组（n=8）：假手术、OVX、局部 ZOL（局部治疗）、全身 ZOL（全身治疗）和局部+全身 ZOL（局部加全身）组。植入后 3 个月，所有动物均被处死并采集标本进行检查。股骨的 BMD 和组织学检查均显示卵巢切除后出现骨质疏松变化，而全身 ZOL 治疗可恢复矿化骨。Micro-CT 检查显示，与假手术对照组相比，OVX 组的矿化骨和种植体-骨接触明显减少，而 ZOL 的全身和局部治疗均显著增加了去卵巢动物的矿化骨和种植体-骨接触。然而，在联合使用 ZOL 的 Loc+Sys-ZOL 组观察到最佳效果，大多数骨指数与（IBCR，p>0.05）或高于（BV/TV、Conn.D 和 Tb.N）（p<0.01）假手术组相似，除了 Tb.Th（p<0.01）仍然显著较低，以及 Tb.Sp（p<0.01）进一步降低。在种植体-骨接触和矿化骨的骨指数的组织形态计量学分析中也证实了上述效果。此外，生物力学测试进一步支持了 ZOL 治疗的有益效果，钛植入物的最大去除扭矩出现在 Loc+Sys-ZOL 组。总之，我们的研究表明，全身和局部使用 ZOL 均可逆转骨质疏松症的负面影响，并促进骨质疏松条件下自体骨移植物中牙种植体的骨整合和固定。与单独使用相比，联合使用全身和局部 ZOL 效果最佳。
