Treatment of gingival recession defects with a coronally advanced flap and a xenogeneic collagen matrix: a multicenter randomized clinical trial

Aim To evaluate the clinical outcomes of the use of a xenogeneic collagen matrix (CM) in combination with the coronally advanced flap (CAF) in the treatment of localized recession defects. Material & Methods In a multicentre single-blinded, randomized, controlled, split-mouth trial, 90 recessions (Miller I, II) in 45 patients received either CAF + CM or CAF alone. Results At 6 months, root coverage (primary outcome) was 75.29% for test and 72.66% for control defects (p = 0.169), with 36% of test and 31% of control defects exhibiting complete coverage. The increase in mean width of keratinized tissue (KT) was higher in test (from 1.97 to 2.90 mm) than in control defects (from 2.00 to 2.57 mm) (p = 0.036). Likewise, test sites had more gain in gingival thickness (GT) (0.59 mm) than control sites (0.34 mm) (p = 0.003). Larger (≥3 mm) recessions (n = 35 patients) treated with CM showed higher root coverage (72.03% versus 66.16%, p = 0.043), as well as more gain in KT and GT. Conclusions CAF + CM was not superior with regard to root coverage, but enhanced gingival thickness and width of keratinized tissue when compared with CAF alone. For the coverage of larger defects, CAF + CM was more effective.