A short-term randomized controlled trial of bilaminar techniques using tunnel versus envelope flap for root coverage in multiple mandibular anterior gingival recessions with thin gingival phenotype

OBJECTIVE: To compare clinical, aesthetic, and patient-reported outcomes of tunnel technique (TUN) versus envelope flap technique (ENV), both combined with connective tissue graft (CTG), for the treatment of multiple mandibular anterior gingival recession defects in patients with thin gingival phenotype. METHODS: Fifty-nine patients contributing 103 recession sites in teeth 33-43 were enrolled. Randomisation was performed at the patient level, and all eligible sites within the same patient received the same intervention. Thirty-four patients (59 sites) received TUN + CTG and 25 patients (44 sites) received ENV + CTG. Clinical outcomes were analysed at the site level with patient-level clustering accounted for using mixed-effects models. Root coverage percentage (RC%), complete root coverage (CRC), keratinized tissue width (KTW), gingival thickness (GT), Root Esthetic Score (RES), and patient-reported outcomes were assessed at 3 and 6 months. RESULTS: At 6 months, mean RC% in the TUN group (79.18 ± 31.49%) was significantly higher than in the ENV group (57.93 ± 37.24%; adjusted mean difference 19.8%, 95% CI 6.9-32.7; P = 0.003). CRC was achieved in 37/59 sites (62.7%) in TUN and 14/44 sites (31.8%) in ENV (adjusted OR 3.36, 95% CI 1.48-7.61; P = 0.004). Both groups showed significant gains in KTW and GT, while RES scores and patient satisfaction were consistently higher in the TUN group. CONCLUSION: Both techniques effectively improved recession defects and soft tissue phenotype in multiple mandibular anterior gingival recessions. The tunnel technique provided superior root coverage, aesthetic integration, and patient satisfaction over 6 months while maintaining a comparable operative time and favourable safety profile.