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.