The aim of this study was to evaluate whether an increased thickness of the gingiva through the use of a free connective tissue graft, in conjunction with a coronally advanced flap procedure, may positively influence the treatment outcome with respect to (i) root coverage and (ii) long-term stability of the position of the soft tissue margin following treatment of recession type defects. 67 consecutive patients having a total of 103 buccally located recession type defects of at least 3 mm were included in the study. After an initial phase of prophylaxis including instructions in a tooth brushing technique giving minimal apically directed forces to the gingival margin, the recession sites were surgically covered with a coronally advanced flap alone (control sites), or coronally advanced flap combined with a free connective tissue graft taken from the palate (test sites). Clinical examinations, including assessments of oral hygiene, gingival conditions, recession depth, gingival height, probing pocket depth and probing attachment loss, were performed before and 6, 12 and 24 months after surgical treatment. The mean initial recession depth for both treatment groups was about 4.0 mm (SD 1.0) with a gingival height apical to the recession of 1.0 mm (0.5). At the re-examination performed 6 months after surgical treatment, the mean recession depth had decreased to 0.2 mm in both the test and control groups. Complete root coverage was observed at 72% of the test sites and 74% of the control teeth. At teeth treated with the combined surgical procedure, the mean gain in probing attachment amounted to 3.7 mm and the mean gingival height had increased to 3.5 mm (0.6). The corresponding figures for control teeth were 3.6 mm and 1.5 mm (0.5), respectively. At the 24-month follow-up examination, the mean root coverage amounted to 98.9% (test) and 97.1% (control). 88% of the teeth in the test group showed complete root coverage compared to 80% for teeth in the control group. It was concluded that the 2 surgical procedures resulted in similar degree of root coverage and that changes of tooth brushing habits may be of greater importance than increased gingival thickness for long-term maintenance of the surgically established position of the soft tissue margin.