Int J Oral Maxillofac Implants. 2024 Oct 16;39(5):755-764. doi: 10.11607/jomi.10780.
Marginal bone resorption (MBR) around dental implants may sometimes be a self-limiting condition due to balancing immunologic reactions against utilized materials rather than a progressive bacterial infection. Contrary to previous assumptions from ligature-induced experimental peri-implantitis studies, a recent 8-week experiment by the present authors showed that marginal ligatures trigger an inflammatory immune response, resulting in bone resorption around implants in the absence of plaque. The present study aimed to investigate whether this inflammatory/immunologic reaction attenuates or progresses toward implant failure after a longer healing time (12 weeks).
Sterile silk ligatures were placed around the top of titanium (Ti) implants and compressed against the femoral cortical bone plate of six rabbits. A nonligated implant was used as a control. After 12 weeks of submerged healing, ground sections of implants and surrounding tissues were investigated with light microscopy. The marginal soft tissues were also analyzed using selected quantitative polymerase chain reaction (qPCR) markers.
Histologically, the ligatures were outlined by immune cells, including multinucleated giant cells (MNGCs), with adjacent fibrous encapsulation and resorbed peripheral bone that contrasted from the osseointegrated nonligated control implants. The difference in expression of qPCR markers was not significant, but > two-fold upregulation of markers CD11b, IL1β, ARG1, NCF1, and CD4 and > twofold downregulation of CD8 indicated a mild, focal inflammatory/immune response against the ligatures compared to controls, with upregulation of M1 and M2 macrophages, neutrophils, and helper T-cells as well as downregulation of killer T cells. Further, the bone formation markers OC and ALPL were > two-fold downregulated (consistent with the lack of osseointegration of the ligatures) compared to control implants.
Marginal silk ligatures trigger an inflammatory/immune response and aseptic bone resorption around implants. Compared to the previous 8-week study, the inflammatory reaction against the silk appears to attenuate with time, with only a mild persisting inflammation that may block osseointegration; instead, a fibrous tissue encapsulation-type reaction is maintained. This may explain why traditional ligature experiments have required regular exchange of ligatures for the bone resorption to progress.
种植体周围的边缘骨吸收（MBR）有时可能是一种自限性疾病，因为它是对所使用材料的免疫反应的平衡，而不是渐进性细菌感染。与先前结扎诱导的实验性种植体周围炎研究的假设相反，本研究作者最近进行的一项为期 8 周的实验表明，边缘结扎会引发炎症免疫反应，导致在没有菌斑的情况下，种植体周围发生骨吸收。本研究旨在探讨在更长的愈合时间（12 周）后，这种炎症/免疫反应是否会减弱或发展为种植体失败。
将无菌丝线结扎在钛（Ti）种植体的顶部，并压在六只兔子的股骨皮质骨板上。未结扎的种植体作为对照。在水下愈合 12 周后，用光学显微镜观察种植体和周围组织的磨片。还使用选定的定量聚合酶链反应（qPCR）标记物分析边缘软组织。
组织学上，结扎物被免疫细胞（包括多核巨细胞（MNGCs））包围，并有相邻的纤维包绕和吸收的周边骨，与非结扎对照种植体形成对比。qPCR 标记物的表达差异不显著，但 CD11b、IL1β、ARG1、NCF1 和 CD4 的表达上调>两倍，CD8 的表达下调>两倍，表明与对照相比，结扎物存在轻度、局灶性炎症/免疫反应，M1 和 M2 巨噬细胞、中性粒细胞和辅助性 T 细胞上调，杀伤性 T 细胞下调。此外，骨形成标记物 OC 和 ALPL 的表达下调>两倍（与结扎物的非骨整合一致）与对照种植体相比。
边缘丝线结扎会引发种植体周围的炎症/免疫反应和无菌性骨吸收。与之前的 8 周研究相比，丝线的炎症反应似乎随着时间的推移而减弱，只有轻度持续的炎症可能会阻止骨整合；相反，保持了纤维组织包裹反应。这可能解释了为什么传统的结扎实验需要定期更换结扎线以使骨吸收进展。
