Dental School, University of Chieti-Pescara, Chieti, Italy.
J Periodontol. 2011 May;82(5):708-15. doi: 10.1902/jop.2010.100450. Epub 2010 Dec 7.
Stability of peri-implant crestal bone plays a relevant role relative to the presence or absence of interdental papilla. Several factors can contribute to the crestal bone resorption observed around two-piece implants, such as the presence of a microgap at the level of the implant-abutment junction, the type of connection between implant and prosthetic components, the implant positioning relative to the alveolar crest, and the interimplant distance. Subcrestal positioning of dental implants has been proposed to decrease the risk of exposure of the metal of the top of the implant or of the abutment margin, and to get enough space in a vertical dimension to create a harmoniously esthetic emergence profile.
The present retrospective histologic study was performed to evaluate dental implants retrieved from human jaws that had been inserted in an equicrestal or subcrestal position. A total of nine implants were evaluated: five of these had been inserted in an equicrestal position, whereas the other four had been positioned subcrestally (1 to 3 mm).
In all subcrestally placed implants, preexisting and newly formed bone was found over the implant shoulder. In the equicrestal implants, crestal bone resorption (0.5 to 1.5 mm) was present around all implants.
The subcrestal position of the implants resulted in bone located above the implant shoulder.
种植体周围骨的稳定性与是否存在牙周膜乳头密切相关。有几个因素可能导致两段式种植体周围的牙槽骨吸收，例如种植体-基台连接部位存在微间隙、种植体与修复体部件之间的连接类型、种植体相对于牙槽嵴的位置以及种植体之间的距离。将种植体置于骨下可以降低暴露种植体顶部金属或基台边缘的风险，并在垂直方向上获得足够的空间来创建协调美观的显露轮廓。
本回顾性组织学研究评估了从人类颌骨中取出的种植体，这些种植体被植入等距或骨下位置。共评估了 9 个种植体：其中 5 个种植体被植入等距位置，而另外 4 个种植体被置于骨下（1 至 3 毫米）。
所有置于骨下的种植体的种植体肩部上方都有预先存在的和新形成的骨。在等距植入的种植体中，所有种植体周围都存在牙槽骨吸收（0.5 至 1.5 毫米）。
种植体的骨下位置导致骨位于种植体肩部上方。
