Guided bone regeneration-associated tissue swelling: A digital three-dimensional assessment.

Statement of problem: Postoperative swelling following guided bone regeneration (GBR) may affect the dimensions of interim restorations and/or delivery timing. However, quantitative assessment of post-GBR swelling or its evaluation for possible impact on regenerative outcomes is lacking.

Purpose: The purpose of this prospective clinical study was to quantify post-GBR swelling and correlate it with clinical parameters and outcomes.

Material and methods: Participants (n=25) undergoing standardized extraction and GBR protocol were recruited. Site-specific swelling was measured as ridge width, height, and volume changes based on intraoral scans recorded preoperatively, immediately postoperatively (IP), and at 2 days, 7 days, 14 days, and 4 months. The parameters and outcomes assessed were gingival and mucosal thickness, flap advancement, surgery duration, wound opening, and bone gain. The Friedman 2-way analysis of variance by ranks was performed, and the Spearman correlation coefficients (ρ) were computed (α=.05).

Results: Ridge width and height peaked at 2 days (2.1 mm for both from IP; P<.001 for both) and reached IP levels by 7 days and 14 days (P>.999 and P=.888, respectively). At 4 months, both decreased significantly compared with IP (-4.2 mm and -1.9 mm respectively, P<.001). Volume increases peaked at 2 days (19%, P<.001), and peak swelling (2 days) preceded maximum wound opening (7 days). Bone width at 4 months was correlated with gingival thickness (ρ=0.45, P=.043), mucosal thickness (ρ=0.51, P=.021), and flap advancement (ρ=0.58, P=.008).

Conclusions: Following GBR, site-specific swelling peaked on postoperative day 2 and subsided by day 7 (width) or 14 (height). Soft tissue thickness and flap advancement affected post-GBR bone width.