Hürzeler M B, Quiñones C R, Schüpbach P
Department of Prosthodontics, Albert-Ludwigs University, Freiburg, Germany.
Clin Oral Implants Res. 1997 Aug;8(4):323-31. doi: 10.1034/j.1600-0501.1997.080411.x.
The aim of this study was to evaluate guided bone regeneration (GBR) around dental implants placed in atrophic alveolar ridges using an experimental, nonporous bioresorbable barrier. In 8 Rhesus monkeys, the maxillary canines and lateral incisors were extracted bilaterally and the remaining alveoli were reduced to create atrophic ridges. After a healing period of 3 months, soft tissue expansion was performed using a subperiosteal tissue expander. After 1 month of tissue expansion, and IMZ implant was placed in the atrophic ridge on each side in such a way that its coronal 4 mm to 5 mm remained circumferentially exposed above the bone level. The test implants were covered with a bioresorbable barrier made of poly (D,L-lactid-co-trimethylencarbonate) in a 70/30 ratio, whereas the control implants were covered with a nonresorbable expanded polytetrafluoroethylene (e-PTFE) barrier. The e-PTFE barriers were stabilized with titanium minipins while the bioresorbable barriers were analogously fixed using bioresorbable minipins made of poly (L-lactid-co-D,L-lactid) 70/30. Clinical healing progressed uneventfully in both groups and no soft tissue dehiscences occurred. Histometric and histomorphometric analyses were performed 5 months post surgery. Both test and control implants exhibited direct bone-to-implant contact to variable extents. The mean direct mineralized bone-to-implant contact length fraction was 32% of the total implant length in the test sites and 58% in the control sites. Control sites exhibited significantly greater bone fill compared to the experimental sites (P < 0.001). Histologic observations of test specimens demonstrated a moderate inflammatory reaction related to the degradation and resorption products of the barrier. In conclusion, the nonresorbable e-PTFE GBR barrier was found to be superior to the bioresorbable barriers tested in the present investigation.
本研究的目的是使用一种实验性的无孔生物可吸收屏障，评估放置在萎缩性牙槽嵴周围的牙种植体周围引导骨再生（GBR）情况。在8只恒河猴中，双侧拔除上颌尖牙和侧切牙，并减少剩余牙槽骨以形成萎缩性牙槽嵴。经过3个月的愈合期后，使用骨膜下组织扩张器进行软组织扩张。组织扩张1个月后，在每侧的萎缩性牙槽嵴中植入一枚IMZ种植体，使其冠部4毫米至5毫米在骨水平以上周向暴露。测试种植体覆盖有由聚（D，L-丙交酯-共-三亚甲基碳酸酯）按70/30比例制成的生物可吸收屏障，而对照种植体覆盖有不可吸收的膨体聚四氟乙烯（e-PTFE）屏障。e-PTFE屏障用钛微型钉固定，而生物可吸收屏障类似地用由聚（L-丙交酯-共-D，L-丙交酯）70/30制成的生物可吸收微型钉固定。两组的临床愈合过程均顺利，未发生软组织裂开。术后5个月进行组织计量学和组织形态计量学分析。测试和对照种植体均在不同程度上表现出骨与种植体的直接接触。测试部位骨与种植体直接矿化接触长度占种植体总长度的平均比例为32%，对照部位为58%。与实验部位相比，对照部位的骨填充明显更多（P < 0.001）。测试标本的组织学观察显示，与屏障的降解和吸收产物相关的中度炎症反应。总之，发现不可吸收的e-PTFE GBR屏障优于本研究中测试的生物可吸收屏障。
