Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), Oporto, Portugal.
Centre of Mathematics, University of Minho, Campus de Azurém, 4800-058, Guimarães, Portugal.
Int J Implant Dent. 2021 Sep 1;7(1):81. doi: 10.1186/s40729-021-00368-1.
Crown-to-implant ratio and crown height space, associated with the use of short implants, have been related with marginal bone loss. However, it is unclear which of the two entities would play the most important role on the bone remodelling process. Using a finite element analysis, the present work aims to help clarifying how those two factors contribute for the stress generation at the marginal bone level. A numerical model (reference model), with a crown-to-implant ratio of 4, was double validated and submitted to a numerical calculation. Then, it was modified in two different ways: (a) by decreasing the prosthetic height obtaining crown-to-implant ratios of 3, 2.5 and 2 and (b) by increasing the implants length obtaining a crown-to-implant ratio of 2.08. The new models were also submitted to numerical calculations.
The reference model showed a marginal bone stress of 96.9 MPa. The increase in the implants' length did not show statistically significant differences in the marginal bone stress (p-value = 0.2364). The decrease in the prosthetic height was accompanied with a statistically significant decrease in the marginal bone stresses (p-value = 2.2e- 16).
The results represent a paradigm change as the crown height space appears to be more responsible for marginal bone stress than the high crown-to-implant ratios or the implants' length. New prosthetic designs should be attempted to decrease the stress generated at the marginal bone level.
与使用短种植体相关的冠-植体比和冠高度空间与边缘骨丧失有关。然而，目前尚不清楚这两个因素中哪一个对骨重塑过程起着最重要的作用。本研究采用有限元分析，旨在帮助阐明这两个因素如何对边缘骨水平的应力产生产生影响。建立了一个具有 4 的冠-植体比的数值模型（参考模型），对其进行了双重验证，并提交数值计算。然后，通过两种不同的方式对其进行了修改：（a）通过减小修复体高度获得冠-植体比为 3、2.5 和 2，（b）通过增加种植体长度获得冠-植体比为 2.08。新模型也提交给数值计算。
参考模型的边缘骨的最大应力为 96.9 MPa。增加种植体长度并没有在边缘骨的最大应力上显示出统计学差异（p 值=0.2364）。修复体高度的降低伴随着边缘骨的最大应力的统计学显著降低（p 值=2.2e-16）。
研究结果代表了一种范式的改变，因为冠高度空间似乎比高冠-植体比或种植体长度更能引起边缘骨的应力。应该尝试新的修复体设计以降低边缘骨水平的应力。
