AIM: The aim of this randomized clinical trial (RCT) was to introduce 3D digital measuring methods for evaluating the outcomes after surgical root coverage (RC) and to assess the clinical performance of the tunnel technique with subepithelial connective tissue graft (TUN) versus the coronally advanced flap (CAF) with enamel matrix derivative in the treatment of shallow localized gingival recession defects. MATERIAL AND METHODS: Twenty-four patients contributed a total of 47 Miller class I or II recessions for scientific evaluation. Clinical outcomes were evaluated at 6 and 12 months. Precise study models gained at baseline and follow-up examinations were optically scanned and virtually superimposed for digital evaluation of clinical outcome measures including percentage of RC and complete root coverage (CRC). Patient-centred outcomes were evaluated with questionnaires. Final aesthetic outcomes were assessed using the root coverage esthetic score (RES). RESULTS: At 12 months, RC was 98.4% for TUN-treated and 71.8% for CAF-treated defects (p = 0.0004). CRC was observed in 78.6% (TUN) and 21.4% (CAF) of the cases (p = 0.0070). Results for patient-centred outcomes were equivalent for both groups but evaluation of the final aesthetic outcomes using the RES revealed a significant difference (9.06 versus 6.92, p = 0.0034) in favour of TUN. CONCLUSIONS: TUN resulted in significantly better clinical outcomes compared with CAF. The new measuring method provided high accuracy and unforeseen precision in the evaluation of treatment outcomes after surgical RC.