Impact of Implant Design on Outcomes of Simultaneous Guided Bone Regeneration for Dehiscence Defects: A Systematic Review and Meta-Analysis

•Although simultaneous guided bone regeneration is commonly performed to manage dehiscence defects during implant placement, complete defect resolution is not consistently achieved.•Compared to bone-level implants, implants with space-maintaining transmucosal collars were found to improve the vertical regeneration achieved, with no differences in the prevalence of wound healing complications.•Replicating the space-maintaining effect of these collars may improve the clinical outcomes of simultaneous GBR. This systematic review and meta-analysis aimed to determine the implications of implant design on the outcomes of simultaneous guided bone regeneration (GBR) to correct dehiscence defects. A structured search strategy was applied to MEDLINE (PubMed), Cochrane Library, and Embase, to identify prospective clinical trials involving implants with simultaneous GBR to correct dehiscence defects. Data regarding implant characteristics, GBR materials, as well as dehiscence defect dimensions at implant placement and surgical re-entry was collected. Meta-analyses were performed to estimate the pooled mean for (1) baseline dehiscence defect dimensions, (2) changes in defect dimensions at re-entry, and (3) prevalence of complete defect resolution. 4298 unique records were identified, of which 21 studies with 680 implants were included. Despite having comparable baseline defect dimensions, greater height gains were achieved by implants with machined collars (MC) than noncollared (NC) implants (4.40 mm, 95% CI [3.70, 5.11] and 3.23 mm, 95% CI [2.72, 3.75] respectively), with significant subgroup differences (P < .01). Specifically, superior outcomes were observed for MC with space-maintaining geometries. However, there were no significant differences in the changes in defect width, prevalence of complete defect resolution, or the prevalence of postsurgical complication rates (P = .15, .54, and .18 respectively). The regenerative outcomes of GBR were influenced by the implant design. Space-maintaining machined collars provide a tenting effect that improves vertical bone gain. While additional research is required to ascertain these findings and integrate choices regarding implant design into clinical decision-making, clinicians may consider replicating this effect to enhance treatment outcomes. [Display omitted]