Sukegawa Shintaro, Yamamoto Norio, Nakano Keisuke, Takabatake Kiyofumi, Kawai Hotaka, Kanno Takahiro, Nagatsuka Hitoshi, Furuki Yoshihiko
Department of Oral and Maxillofacial Surgery, Kagawa Prefectural Central Hospital, 1-2-1, Asahi-machi, Takamatsu, Kagawa 760-8557, Japan.
Department of Orthopaedic Surgery, Kagawa Prefectural Central Hospital, Takamatsu, Kagawa 60-0065, Japan.
Materials (Basel). 2020 Jul 15;13(14):3153. doi: 10.3390/ma13143153.
Osteosynthesis resorbable materials made of uncalcined and unsintered hydroxyapatite (u-HA) particles, poly-L-lactide (PLLA), are bioresorbable, and these materials have feasible bioactive/osteoconductive capacities. However, their strength and stability for fixation in mandibular condylar head fractures remain unclear. This in vitro study aimed to assess the biomechanical strength of u-HA/PLLA screws after the internal fixation of condylar head fractures. To evaluate their biomechanical behavior, 32 hemimandible replicas were divided into eight groups, each consisting of single-screw and double-screw fixations with titanium or u-HA/PLLA screws. A linear load was applied as vertical and horizontal load to each group to simulate the muscular forces in condylar head fractures. Samples were examined for 0.5, 1, 2, and 3-mm displacement loads. Two screws were needed for stable fixation of the mandibular condylar head fracture during biomechanical evaluation. After screw fixation for condylar head fractures, the titanium screws model was slightly more resistant to vertical and horizontal movement with a load for a small displacement than the u-HA/PLLA screws model. There was no statistically significant difference with load for large displacements. The u-HA/PLLA screw has a low mechanical resistance under small displacement loading compared with titanium within the limits of the mandibular head fracture model study.
由未煅烧和未烧结的羟基磷灰石（u-HA）颗粒与聚-L-丙交酯（PLLA）制成的骨合成可吸收材料具有生物可吸收性，并且这些材料具有可行的生物活性/骨传导能力。然而，它们在下颌髁突头部骨折固定中的强度和稳定性仍不清楚。这项体外研究旨在评估髁突头部骨折内固定后u-HA/PLLA螺钉的生物力学强度。为了评估它们的生物力学行为，将32个半下颌骨模型分为八组，每组由钛螺钉或u-HA/PLLA螺钉的单螺钉和双螺钉固定组成。对每组施加线性载荷作为垂直和水平载荷，以模拟髁突头部骨折中的肌肉力量。对样本进行0.5、1、2和3毫米位移载荷的检查。在生物力学评估过程中，下颌髁突头部骨折的稳定固定需要两颗螺钉。在髁突头部骨折进行螺钉固定后，与u-HA/PLLA螺钉模型相比，钛螺钉模型在小位移载荷下对垂直和水平移动的抵抗力略强。在大位移载荷下没有统计学上的显著差异。在下颌头部骨折模型研究的范围内，与钛相比，u-HA/PLLA螺钉在小位移载荷下的机械阻力较低。
