Periimplantitis and soft-tissue defects of dental implants: A pilot study on the fixing of the suprastructure as a possible factor affecting aetiology

种植体周围骨的炎性破坏(种植体周围炎)是晚期种植体丢失的最常见原因。对于支持粘固性上部结构的种植体，一个可能的原因是种植体周围软组织中存在未被检测到的过量粘固剂，特别是当使用标准基牙时，当粘固剂间隙在牙龈下时。个别基牙可能不会面临这个问题，因为水泥盖子可以被建造成可以清洗，但目前还没有数据。这项先导性研究将在20名患者身上进行，比较标准基牙和个别基牙。这项初步研究的主要目的是在探索性检查的两周后，量化标准基牙和单个基牙以及种植体支持的单冠种植体周围软组织中未检测到的过剩粘固剂。对于每个基牙，将检查4个测量点(颊、舌、远中、近中)。无水泥面层和未检测到的过剩水泥面层的比例的位置和分布将以平均值和标准差显示，并以框图显示。此外，还将检查种植体周围软组织的体积变化或炎症迹象，并记录丧失固位力的情况。种植体支持的单冠制造的所有工作步骤将仅由一名牙医和一名牙科技师执行。为避免偏见，将进行随机化，研究中的所有调查将由两名经过校准的调查人员进行，他们在任何时候都没有参与牙科治疗。海德堡大学医学生物计量和信息学研究所(IMBI)将参与这项从规划到统计分析的研究。种植体周围炎的病因很多，大多未知，而且发病率正在急剧增加。这项试点研究将能够计算主要研究的样本量，这将是在法兰克福大学和海德堡大学进行的一项多中心研究，也是在现有的实践网络内进行的，以强调这项研究的临床相关性。主要研究的目的将是制定治疗建议，使种植体周围软组织中未被检测到的过量水泥得以避免，这可能是种植体周围炎的一个病因。

Inflammatory destruction of the periimplant bone (periimplantitis) is the most common reason for late implant loss. For implants supporting cemented suprastructures, a possible reason is the presence of undetected excess cement in the periimplant soft tissue, especially when standard abutments are used, when the cement gap is subgingival. Individual abutments might not face this problem, because the cement cap can be constructed so it is cleanable, but no data are yet available. This pilot-study will be conducted on 20 patients, comparing standard and individual abutments. The primary endpoint of the pilot study is to quantify undetected excess cement on standard and individual abutments and in the soft tissue around the implants with implant-supported single crowns after two weeks within an exploratory examination. For each abutment, 4 measurement points will be examined (buccal, lingual, distal, mesial). Position and distribution of the ratios of cement-free surface and surface with undetected excess cement will be shown as mean and standard deviation and displayed as box-plots. In addition, the periimplant soft tissue will be examined for volumetric changes or signs of inflammation, and cases of loss of retention will also be documented. All working steps in fabrication of the implant-supported single crowns will be performed by one dentist and one dental technician only. To avoid bias, randomization will be performed and all investigations in the study will be performed by two calibrated investigators who did not participate in the dental treatment at any time. The Institute of Medical Biometry and Informatics (IMBI) of the University of Heidelberg will be involved in the study from planning to statistical analysis. The aetiology of periimplantitis is numerous and mostly unknown, and the incidence is increasing drastically. This pilot study will enable calculation of sample size for a main study, which will be a multicentre study performed at the Universities of Frankfurt and Heidelberg, and within the existing practice network also, to emphasize the clinical relevance of this investigation. The purpose of the main study will be to formulate recommendations for treatment which enable undetected excess cement in the peri-implant soft tissue, a possible aetiological factor of periimplantitis, to be avoided.