Organo-chemical modification of titanium alloy and zirconia surfaces to achieve tight gingival adhesion (GingiSeal)

使用种植牙的口腔康复为治疗牙齿脱落的患者提供了几种选择，从而为他们提供了更好的生活质量。除了种植体与牙槽骨的整合外，周围软组织与种植体上构造（基台）材料表面的附着也起着至关重要的作用。然而，种植体周围的粘膜与天然牙齿有显著的差异。在种植体支持的修复中，粘膜和牙齿之间的天然“密封”是由所谓的连接上皮保证的。因此，细菌更容易渗透到种植体和牙槽骨之间的界面，并随后在种植体和牙槽骨之间的界面引发病理过程。在GingiSeal研究项目的第一阶段，通过自组装单层（SAM）修饰基牙材料氧化锆（Y-TZP）和已建立的钛合金（Ti6Al4V），并在合适的交联剂的帮助下与细胞外基质（ECM）蛋白进一步功能化。人类牙龈成纤维细胞的体外实验表明，与未经处理的表面相比，有机化学修饰表面显著增强了细胞粘附、细胞增殖、细胞扩散和整合素表达。除了在体外模拟口腔状况（这是该项目第一阶段仍需完成的任务）之外，还出现了一些重要的问题。在项目的第二阶段，研究功能化基牙表面与牙龈上皮细胞之间的粘附机制是非常重要的。此外，质谱法将用于确定交联剂如何与ECM的蛋白质相互作用。此外，细菌DNA的含量在不同的修饰表面将通过qPCR测定。此外，将利用生物打印技术制备牙龈粘膜的三维体外模型。然后将由各种细菌菌株组成的生物膜应用于修饰/未修饰基台材料和生物打印粘膜替代品之间的界面。3D模型将用于确定打印软组织对改良基台材料的附着力增加是否对细菌不渗透。为此，将进行活死染色，通过ELISA检测打印的牙龈粘膜细胞因子的释放，并使用乳酸脱氢酶（LDH）试验分析生物膜诱导的细胞毒性。如果项目进展顺利，生物打印体外3D模型的实验结果将为两年后设想的临床试点研究奠定基础。

Oral rehabilitation using dental implants provides several options for treating patients with tooth loss, thereby offering them better quality of life. In addition to the integration of the implant into the alveolar bone, the attachment of the surrounding soft tissue to the material surface of the implant's supraconstruction (abutment) plays an essential role. However, the peri-implant mucosa exhibits significant differences compared to that of a natural tooth. The natural ”seal” at the interface between mucosa and tooth, which is ensured by the so-called junctional epithelium, is missing in an implant-supported restoration. Thus, bacteria can easier penetrate into the interface and can subsequently provoke pathological processes at the interface between implant and alveolar bone. In the first phase of the research project GingiSeal, the abutment materials zirconia (Y-TZP) and the established titanium alloy (Ti6Al4V) were modified by self-assembled monolayers (SAM) and further functionalized with proteins of the extracellular matrix (ECM) with the help of a suitable cross linker. In-vitro experiments with human gingival fibroblasts have shown significantly enhanced cell adhesion, cell proliferation, cell spreading, and integrin expression on the organo-chemically modified surfaces compared to untreated surfaces. In addition to the mimicry of oral conditions in-vitro, which are tasks still to be completed within the first phase of the project, important further questions have arisen. In the second phase of the project, the exact adhesion mechanisms between the functionalized abutment surfaces and gingival epithelial cells is of importance. Furthermore, mass spectrometry will be used to determine how the crosslinker interacts with the proteins of the ECM. Furthermore, the bacterial DNA content on the differently modified surfaces will be determined via qPCR. In addition, a three-dimensional in vitro model of a gingival mucosa will be fabricated using bioprinting technology. A biofilm consisting of various bacteria strains is then applied to the interface between the modified/unmodified abutment material and the bioprinted mucosa substitute. The 3D model will be used to determine whether increased adhesion of the printed soft tissue to the modified abutment materials is impermeable to bacteria. For this purpose, live-dead staining will be performed, cytokine release from the printed gingival mucosa will be investigated by ELISA, and biofilm-induced cytotoxicity will be analyzed using a lactate dehydrogenase (LDH) assay. If the project progresses positively, the findings from the experiments with the bioprinted in vitro 3D model will form the foundation for a clinical pilot study envisaged after the two years.