Tunnel Technique for Root Coverage procedures: a systematic review and meta-analysis for short- and long-term studies

Abstract

Background: Tunneling technique (TUN) has showed its effectiveness as a root coverage procedure. However, coronally advanced flap (CAF) procedure was still superior to it and long-term comparisons were lacking. Therefore, this systematic review and meta-analysis aimed to determine the effectiveness of TUN in comparison to CAF, as well as to investigate the stability of the results on the long-term. Methods: A systematic search of the following websites: MEDLINE, EMBASE, Cochrane library, in addition to, hand-search journals till April 2022. Only randomised controlled trials, investigating TUN and its modifications compared to CAF for the treatment of gingival recessions, were considered. Subgroup analyses were performed to investigate the impact of the type of the graft that has been used and the type of the recessions. Results: We included eleven trials in our systematic review and meta-analysis. Three of which are considered to have a high risk of bias, while four had an unclear risk of bias. The rest of them had a low risk of bias. Tunneling technique achieved a total mean root coverage (mRC) of 86% for short-term and 83.5% for long-term follow-ups. An overall complete root coverage (CRC) of 59% and 54% for short-and long-term trials, respectively. In terms of mRC, CRC, clinical attachment (CAL), keratinised tissue width (KTW), gingival thickness (GT), root coverage esthetic score, and patient-centred outcomes, tunnelling and CAF had comparable results. Nevertheless, CRC, CAL gain, and KTW gain showed favourable results with CAF, when Acellular Dermal Matrix (ADM) is used as the graft. Conclusion: There is no evidence of a difference between TUN and CAF in treating gingival recessions. When a graft is considered, connective tissue graft (CTG) can enhance the attained clinical 6 outcomes for both techniques, while ADM showed better clinical outcomes with CAF. KTW and GT gain may influence the long-term stability.