Yamada Yutaka, Nanba Koichi, Ito Koichi
Nihon University Graduate School of Dentistry, Tokyo, Japan.
Clin Oral Implants Res. 2003 Aug;14(4):455-63. doi: 10.1034/j.1600-0501.2003.00832.x.
We evaluate the effects of occlusiveness of a titanium cap on bone generation beyond the skeletal envelope. In eight rabbits, the calvarial bone was exposed and a circular groove was prepared with a trephine drill. After marrow penetration, a standardized hemispherical titanium cap, either with or without small holes (1.5 mm in diameter), was then placed into the bone and covered by a cutaneous flap. After 1 month or 3 months of healing, the animals were euthanized and examined histologically. The percentage area of newly generated tissue consisting of mineralized bone and marrow spaces in each section was calculated relative to the area bounded by the hemispherical shape of the titanium cap and the parent bone; this latter volume was taken to be 100%. Furthermore, the cross-sectional areas of generated mineralized bone expressed as percentages of the total tissue area generated within each space were determined. In the 1-month specimens, there was no statistically significant difference between the two caps in the amount of tissue generated, 54.7%+/-12.2% with holes vs. 60.4%+/-8.8% without holes (p=0.225). However, in the 3-month specimens, we observed a significant difference between the caps (55.9%+/-7.4% with holes vs. 89.9%+/-6.5% without holes, P<0.05). Also, there was a statistically significant difference between 1- and 3-month specimens in the amount of tissue generated under the cap without holes (60.4%+/-8.8% vs. 89.9%+/-6.5%, P<0.05). Although there was no significant difference in the relative amount of mineralized bone generated between the caps with holes and those without holes in the 1-month specimens (27.7%+/-4.8% vs. 30.8%+/-6.4%, P=0.225), there was a statistically significant difference between the two caps in the 3-month specimens (24.3%+/-4.1% with holes vs. 34.0%+/-8.6% without holes, P<0.05). A substantial ingrowth of fibrous connective tissue through the holes appeared to prevent further new tissue generation in a defined area adjacent to the bone surface. We concluded that total occlusiveness, sufficient stiffness of the cap, as well as the passage of time will allow predictable mineralized bone augmentation to occur in spaces beyond the skeletal envelope.
我们评估了钛帽的封闭性对骨骼包膜外骨生成的影响。在八只兔子身上，暴露颅骨，并用环钻制备一个圆形凹槽。穿透骨髓后，将一个标准化的半球形钛帽（有或没有直径1.5毫米的小孔）放入骨中，并用皮瓣覆盖。愈合1个月或3个月后，对动物实施安乐死并进行组织学检查。计算每个切片中由矿化骨和骨髓腔组成的新生成组织的面积百分比，相对于由钛帽的半球形形状和母骨界定的面积；后一个体积被视为100%。此外，确定生成的矿化骨的横截面积占每个空间内生成的总组织面积的百分比。在1个月的标本中，两种钛帽在生成的组织量上没有统计学显著差异，有孔的为54.7%±12.2%，无孔的为60.4%±8.8%（p = 0.225）。然而，在3个月的标本中，我们观察到两种钛帽之间存在显著差异（有孔的为55.9%±7.4%，无孔的为89.9%±6.5%，P<0.05）。而且，在无孔钛帽下，1个月和3个月标本在生成的组织量上也存在统计学显著差异（60.4%±8.8%对89.9%±6.5%，P<0.05）。尽管在1个月的标本中，有孔钛帽和无孔钛帽之间生成的矿化骨相对量没有显著差异（27.7%±4.8%对30.8%±6.4%，P = 0.225），但在3个月的标本中，两种钛帽之间存在统计学显著差异（有孔的为24.3%±4.1%，无孔的为34.0%±8.6%，P<0.05）。纤维结缔组织通过孔大量向内生长，似乎阻止了骨表面相邻特定区域进一步生成新组织。我们得出结论，完全封闭、钛帽足够的硬度以及时间的推移将使骨骼包膜外空间可预测地发生矿化骨增加。
