Abstract
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).
Highlights
Against the background of increasing use of dental implants, and an increasing prevalence of implant-associated complications, a deeper understanding of the biomolecular mechanisms in the peri-implant tissue is needed
There is only low-level evidence available on the interaction between different abutment materials with peri-implant tissues [13, 14]. It has been suggested in histological studies that the abutment materials may have an influence on the stability of peri-implant tissues [4, 5, 15], clinical studies that compared titanium to aluminum oxide abutments [16, 17] and titanium to gold-alloy abutments [18] found no significant differences in the clinical parameters
There is a lack of studies on lithium disilicate compared with titanium and zirconia as dental implant abutment material
Summary
Against the background of a high prevalence of biological peri-implant complications [3], the mechanisms of the interface between peri-implant soft tissue and transmucosal abutments are of interest. Only one recently published cross-sectional clinical study [39] has investigated the interaction of abutment materials (titanium versus zirconia) with peri-implant tissue by means of PICF marker analyses. The interaction between the three abutment materials with the peri-implant soft tissue should not be biased by different surface roughness in the present study. Each abutment material is circularly in contact with open wound edges, and the 1-month PICF sampling takes place during the early wound healing period for each of the three abutments This is a clinically relevant procedure especially for the “one abutment – one time” concept, where the definitive abutment is inserted directly after implantation (direct loading) or directly after second-stage surgery (delayed loading) without removing it again [48,49,50].
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