Interaction of titanium, zirconia and lithium disilicate with peri-implant soft tissue: study protocol for a randomized controlled trial

BackgroundAgainst the background of increasing use of dental implants, and thus an increasing prevalence of implant-associated complications, a deeper understanding of the biomolecular mechanisms in the peri-implant tissue is needed. Peri-implant soft tissue is in direct contact with transmucosal dental implant abutments. The aim of this trial is to distinguish the biomolecular and histological interactions of various dental abutment materials with peri-implant soft tissue.Methods/DesignThe study is designed as a prospective, randomized, investigator-initiated clinical pilot trial with blinded assessment. We will ultimately include 24 eligible patients who opt for implant treatment to replace a single missing posterior tooth. Three months after implantation (submerged procedure), the study begins with the second-stage surgery. Each of the 24 patients will be given three different transmucosal abutments (zirconia, lithium disilicate, titanium) consecutively. The sequence in which the three materials are used is randomized. Peri-implant crevicular fluid is sampled weekly around the respective abutment for biomolecular analyses. After one month of wearing time, the stamping press from the second-stage surgery is used to gain a narrow gingival ring biopsy around the abutment for immunohistochemical analyses. The next abutment is then inserted. The same procedure is used for all three abutments. After sampling is completed, the patients will receive a definitive crown. The primary outcome measure of the trial is biomolecular detection of specific markers in the peri-implant crevicular fluid: matrix metalloproteinase 8, interleukin- 1β, polymorphonuclear elastase, and myeloid-related protein MRP8/14 (calprotectin). Secondary outcome measures include immunohistochemical analyses and clinical parameters.DiscussionThe study design will allow us to perform correlation analyses between the clinical indices with biomarkers’ expression in the interface of the transmucosal abutments and the peri-implant soft tissue. A deeper understanding of the three abutment materials’ interactions with peri-implant soft tissue will help us understand the formation mechanisms of implant-associated complications and then develop prevention strategies.Trial registrationThe trial is registered at the German Clinical Trial Register and the International Clinical Trials Registry Platform by the WHO under DRKS00006555 (Registered on 27 October 2014).

背景 在牙科植入物使用日益增加以及植入相关并发症患病率不断上升的背景下，需要对种植体周围组织的生物分子机制有更深入的了解。种植体周围软组织与穿黏膜牙科种植体基台直接接触。本试验的目的是区分各种牙科基台材料与种植体周围软组织的生物分子和组织学相互作用。 方法/设计 本研究设计为一项前瞻性、随机、由研究者发起且评估设盲的临床试验性研究。我们最终将纳入24名符合条件且选择植入治疗来替换单颗缺失后牙的患者。植入（埋入式手术）3个月后，研究从二期手术开始。24名患者每人将依次接受3种不同的穿黏膜基台（氧化锆、二硅酸锂、钛）。3种材料的使用顺序是随机的。每周在相应基台周围采集种植体周围龈沟液用于生物分子分析。佩戴1个月后，利用二期手术的印模器在基台周围获取窄的牙龈环形活检组织用于免疫组织化学分析。然后插入下一个基台。对所有3个基台都采用相同的程序。采样完成后，患者将接受最终的牙冠修复。试验的主要结局指标是种植体周围龈沟液中特定标志物的生物分子检测：基质金属蛋白酶8、白细胞介素 - 1β、多形核弹性蛋白酶以及髓系相关蛋白MRP8/14（钙卫蛋白）。次要结局指标包括免疫组织化学分析和临床参数。 讨论 该研究设计将使我们能够对穿黏膜基台与种植体周围软组织界面处的临床指标和生物标志物表达进行相关性分析。对3种基台材料与种植体周围软组织相互作用的更深入理解将有助于我们了解植入相关并发症的形成机制，进而制定预防策略。 试验注册 该试验已在德国临床试验注册中心以及世界卫生组织的国际临床试验注册平台注册，注册号为DRKS00006555（2014年10月27日注册）