Thin-phenotype lower recessions: the tunnel beats the envelope flap

In the most demanding zone for periodontal plastic surgery — multiple mandibular anterior recessions on a thin gingival phenotype — which approach delivers better coverage? This randomized controlled trial enrolled 59 patients contributing 103 recession sites (teeth 33-43). Randomisation was at patient level: 34 patients (59 sites) received the tunnel technique plus connective tissue graft (TUN + CTG), and 25 patients (44 sites) received the envelope flap plus CTG (ENV + CTG). Site-level outcomes were analysed with mixed-effects models accounting for patient clustering, at 3 and 6 months.

At 6 months, mean root coverage was significantly higher with the tunnel (79.18 ± 31.49%) than the envelope (57.93 ± 37.24%; adjusted mean difference 19.8%, 95% CI 6.9-32.7; P=0.003). Complete root coverage was achieved in 62.7% of tunnel sites versus 31.8% of envelope sites (adjusted OR 3.36, 95% CI 1.48-7.61; P=0.004). Both techniques produced significant gains in keratinized tissue width and gingival thickness, while Root Esthetic Score and patient satisfaction were consistently higher in the tunnel group — at comparable operative time and a favourable safety profile.

The clinical signal is clear: both flaps improve the recession and the soft-tissue phenotype, but in thin-phenotype lower incisors the tunnel offers more predictable and more complete coverage without an added operative cost. At 6 months this is a short-term read; longer follow-up would confirm whether the coverage advantage holds.