The Influence of a New Implant Neck Configuration on Hard and Soft Tissue Healing

Overview

Title: Randomized Controlled Clinical Trial comparing two dental implants with different neck configurations. Objective: To evaluate the changes in peri-implant soft tissues and marginal bone level when using a one-piece implant with a widening transgingival machined collar and a one-piece implant with a tapering transgingival machined collar. Design: The study will be a prospective parallel randomized clinical trial with a 12 month follow up conducted in 5 private dental practices. A total of 50 patients meeting the inclusion criteria will be randomized in one of the two groups to receive 1 single implant placed in healed ridges. Radiographic and clinical measurements will be taken post-insertion, baseline (post-loading) 6 and 12 months after loading. Study Hypothesis: The hypothesis of this study is that there will be no differences in the preservation of the peri-implant marginal bone level and peri-implant soft tissues between the two implant neck designs.

The study will be a prospective parallel randomized clinical trial (RCT) of approximately 20 months of duration, in which each patient will receive 1 implants placed in the posterior mandible. If the patients fulfill the inclusion criteria after implant site preparation, they will be randomized to either receive an implant with a one-piece tapering neck configuration (P) or with a widening neck configuration (TL). 52 patients, male or female, aged 18 or older, who are missing one tooth in the posterior mandible (positions 4-6). A randomization list will determine which implant type has to be inserted. This randomization list will be generated by an independent investigator. Patients will be recruited by the investigator consecutively. Prior to implant site preparation, the clinician will determine if the patient still meets the inclusion criteria at surgery in particular if the bone quantity is sufficient. Patients who do not meet the inclusion criteria will be excluded from the study and will therefore not be randomized. The patients will be randomized to receive P implant or TL implant. For both groups, impression will be taken 8 weeks post insertion. Details with regard to the prosthetic procedures and materials used for the restoration of the implants will be provided in a separate section of this protocol. Standardized peri-apical radiographs will be taken before and after prosthesis placement to document the crestal bone level at the day of loading. Standardized photographs will be taken to measure the soft tissue at the time of loading. The thickness of the soft tissue will be measured 2 mm apical to the gingival margin with a needle. Routine controls are due at 6 and 12 months post loading. Peri-apical radiographs will be taken after implant placement, before/after loading and at 12 months post loading. Final impressions will be taken at 12 months post loading to evaluate volumetric changes.