Comparing Single Tooth Implant Placement With and Without Allogenic Soft Tissue Augmentation. A Randomized Clinical Trial.

Abstract

To explore the effect of adding an allogenic soft tissue graft at time of single implant placement using a fully digital workflow for single implant placement and restoration without making either analog or digital impressions. A prospective randomized clinical study was performed enrolling thirtynine participants requiring single tooth implant randomized into (+ graft) group which received an allogenic dermal graft at the time of implant placement (n=19), or (- graft) group (n=20). A fully digital surgical and restorative protocol was implemented. Intraoral scans were taken before implant placement (T0), at time of final crown delivery (T1) and at one-year post placement (T2). Intraoral scans were aligned using Geomagic Control X 2020 software), linear and volumetric changes in buccal tissues were measured at T0, T1 and T2. Implant survival, probing depths, and complications were recorded. Participants were asked to complete an OHIP-14 survey at T0 and T2. Marginal bone levels were measured at T0 and T2 on peri-apical x-rays. 39 participants completed surgery and restoration in incisor, canine, premolar and molar positions. Two early failures were recorded in central incisor positions (95% survival). Crown delivery without complication from the digital workflow (impressionless) was achieved for 36/39 of cases (92%) with implant depth control being implicated as the chief challenge. Thirtyseven participants attended the one-year follow-up visit. Both groups showed gain in buccal tissues thickness without significant differences between the two groups for both linear and volumetric measurements (P>0.05). Soft tissue grafting was associated with minimal added morbidity. The interproximal marginal bone changes recorded were -0.16mm mesial and - 0.12mm distal for the graft group and -0.01mm mesial and -0.11mm distal for the non-graft group (p=0.07 for mesial and 0.83 for distal). OHIP score was significantly reduced at T2 compared to T0 (P=0.003) for the entire cohort. The augmentation of alveolar mucosa on the buccal aspect of single tooth implants is associated with clinically favorable outcomes. A fully digital workflow has been validated to permit crown delivery on CAD/CAM abutments without implant impressions.