Osmotic swelling and residual stress are increasingly recognized as important factors in soft tissue biomechanics. Little attention has been given to residual stress in periodontal ligament (PDL) biomechanics despite its rapid growth and remodeling potential. Those tissues that bear compressive loads, e.g., articular cartilage, intervertebral disk, have received much attention related to their capacities for osmotic swelling. To understand residual stress and osmotic swelling in the PDL, it must be asked (1) to what extent, if any, does the PDL exhibit residual stress and osmotic swelling, and (2) if so, whether residual stress and osmotic swelling are mechanically significant to the PDL’s stress/strain behavior under external loading. Here, we incrementally built a series of computer models that were fit to uniaxial loading, osmotic swelling and residual stretch data. The models were validated with in vitro shear tests and in vivo tooth-tipping data. Residual stress and osmotic swelling models were used to analyze tension and compression stress (principal stress) effects in PDL specimens under external loads. Shear-to-failure experiments under osmotic conditions were performed and modeled to determine differences in mechanics and failure of swollen periodontal ligament. Significantly higher failure shear stresses in swollen PDL suggested that osmotic swelling reduced tension and thus had a strengthening effect. The in vivo model’s first and third principal stresses were both higher with residual stress and osmotic swelling, but smooth stress gradients prevailed throughout the three-dimensional PDL anatomy. The addition of PDL stresses from residual stress and osmotic swelling represents a unique concept in dental biomechanics.

渗透肿胀和残余应力越来越被认为是软组织生物力学中的重要因素。尽管牙周韧带 (PDL) 生物力学具有快速增长和重塑潜力，但很少有人关注其残余应力。那些承受压缩负荷的组织，例如关节软骨、椎间盘，因其渗透肿胀能力而受到广泛关注。要了解 PDL 中的残余应力和渗透膨胀，必须询问（1）PDL 是否在多大程度上（如果有）表现出残余应力和渗透膨胀，以及（2）如果有，残余应力和渗透膨胀是否是机械性的对 PDL 在外部载荷下的应力/应变行为具有重要意义。在这里，我们逐步建立了一系列适合单轴加载的计算机模型，渗透膨胀和残余拉伸数据。这些模型通过体外剪切试验和体内牙齿倾斜数据进行了验证。残余应力和渗透膨胀模型用于分析 PDL 试样在外部载荷下的拉伸和压缩应力（主应力）效应。在渗透条件下进行剪切失效实验并建模以确定肿胀牙周韧带的力学和失效的差异。膨胀的 PDL 中显着更高的破坏剪切应力表明渗透膨胀降低了张力，因此具有强化作用。体内模型的第一和第三主应力​​均较高，残余应力和渗透膨胀，但平滑的应力梯度在整个三维 PDL 解剖结构中占主导地位。