Huang B, Zhang L, Xu L, Zhu W, Witek L, Tovar N, Coelho P-G, Meng H
Department of Periodontology, Peking University, School and Hospital of Stomatology, zhongguancun nandajie No.22, Haidian District, Beijing 100081, China,
Med Oral Patol Oral Cir Bucal. 2018 Jan 1;23(1):e30-e37. doi: 10.4317/medoral.22032.
The subcrestal placement of implant platform has been considered a key factor in the preservation of crestal bone, but the influence of implant placement depth on bone remodeling combined with peri-implantitis is not fully understood. The aim of this study was to assess the effect of the crestal or subcrestal placement of implants on peri-implant bone defects of ligature-induced peri-implantitis in dogs.
Eight weeks after tooth extraction in six beagle dogs, two different types of implants (A: OsseoSpeed(TM), Astra, Molndal, Sweden; B: Integra-CP(TM), Bicon, Boston, USA) were placed at either crestal or subcrestal (-1.5 mm) positions on one side of the mandible. Ligature-induced peri-implantitis was initiated four weeks after the installation of the healing abutment connections. After 12 weeks, tissue biopsies were processed for histological analyses.
Supra-alveolar bone loss combined with a shallow infrabony defect was observed in crestal level implants while deep and wide infrabony defects were present in subcrestal level groups. Subcrestal groups showed significantly greater ridge loss, depths and widths of infrabony defects when compared to crestal groups (P <0.001).
Within the limitations of the animal study, it can be stated that the implants at subcrestal position displayed greater infra-osseous defect than implants at crestal position under an experimental ligature-induced peri-implantitis.
种植体平台的龈下放置被认为是保存牙槽嵴骨的关键因素，但种植体放置深度对骨重塑以及种植体周围炎的影响尚未完全明确。本研究的目的是评估种植体的龈上或龈下放置对犬结扎诱导性种植体周围炎种植体周围骨缺损的影响。
6只比格犬拔牙8周后，在一侧下颌骨的龈上或龈下（-1.5mm）位置植入两种不同类型的种植体（A：OsseoSpeed™，Astra，瑞典莫伦达尔；B：Integra-CP™，Bicon，美国波士顿）。在安装愈合基台连接4周后引发结扎诱导性种植体周围炎。12周后，对组织活检样本进行组织学分析。
龈上水平种植体观察到牙槽嵴上骨质流失并伴有浅的骨下缺损，而龈下水平组存在深且宽的骨下缺损。与龈上组相比，龈下组的牙槽嵴吸收、骨下缺损的深度和宽度显著更大（P<0.001）。
在动物研究的局限性范围内，可以得出结论，在实验性结扎诱导性种植体周围炎情况下，龈下位置的种植体比龈上位置的种植体显示出更大的骨下缺损。
