Failure of root coverage of shallow gingival recessions employing GTR and a bioresorbable membrane

The aim of the present study was to compare the postsurgical outcome of two different modes of surgical root coverage of predominantly shallow, Class I or II, gingival recessions. Fourteen facial recessions in nine patients w ere subjected to a coronally repositioned flap in combination with a biores orbable membrane, and 14 sites in 13 patients were treated with a connectiv e tissue graft employing an envelope technique. Immediately before surgery and after 6 and 12 months, gingival dimensions as well as root coverage and attachment gain were assessed. At baseline, mean recession depths amounted to 2.77 +/- 1.67 mm and 2.49 +/- 7.07 mm for patients treated with a biore sorbable membrane and a free connective tissue graft, respectively. Accepta ble and stable root coverage of 81% to 82% of baseline recession depth and 78% of its width was achieved by grafting. In contrast, guided tissue regen eration (GTR) resulted in only 50% coverage of recession depth and, after 1 2 months, only 11% of its width (P < 0.01). Logistic regression revealed th at the odds of obtaining success, ie, at least 80% root coverage, were 3.3 times greater in cases treated with a connective tissue graft (P < 0.05). I n addition, the odds ratio was 2.3 in cases of recessions below 2.5 mm comp ared to deeper recessions and 2 at canines compared to premolars. It was co ncluded that shallow recessions in the 1.5 to 3.5 mm range should not be tr eated with GTR. In these situations, predictable results are achieved with free connective tissue grafts employing an envelope technique.