One-year re-entry results of guided bone regeneration around immediately placed implants with immediate or conventional loading: a case series.

The aim of this one-year, re-entry case series was to evaluate clinically the amount of bone regeneration following the placement of immediate implants in fresh extraction sockets where bone allograft has been used to treat horizontal gaps and buccal-bone dehiscence defects in periodontally compromised patients. Sixteen patients consented to participate, each having one immediate implant with > 3 mm buccal dehiscence bone defects and > or = 2 mm horizontal defects between the implant and socket wall. Peri-implant defects were treated using a demineralized freeze-dried bone allograft and a bioresorbable collagen membrane. Measurements of the vertical and horizontal bone defects were performed at 4 sites: buccally, mesially, distally and lingually, and were done at baseline and at 1-year follow-up. The mean reduction in vertical defects between baseline and re-entry for all sites was 2.42 mm (p = 0.0005). Compared to lingual sites, the buccal sites showed the greatest resolution in vertical defects dimension (6.37 mm), followed by proximal sites (0.78 mm). The overall mean reduction in horizontal defects was 1.59 mm (p < 0.0001). Compared to lingual sites, the buccal sites showed the greatest resolution in horizontal gap dimension (3.2 mm), followed by proximal sites (0.8 mm). Age, defect location in the mouth and implant length did not show significant effectson the reduction in defect dimension during the first year. A partially missing buccal plate was not a critical factor for implant success and bone regeneration of immediate implants in patients with a history of periodontal disease regardless of the time of implant loading (immediate/conventional).