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 were subjected to a coronally repositioned flap in combination with a bioresorbable membrane, and 14 sites in 13 patients were treated with a connective 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+/-1.07 mm for patients treated with a bioresorbable membrane and a free connective tissue graft, respectively. Acceptable 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 regeneration (GTR) resulted in only 50% coverage of recession depth and, after 12 months, only 11% of its width (P < 0.01). Logistic regression revealed that 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). In addition, the odds ratio was 2.3 in cases of recessions below 2.5 mm compared to deeper recessions and 2 at canines compared to premolars. It was concluded that shallow recessions in the 1.5 to 3.5 mm range should not be treated with GTR. In these situations, predictable results are achieved with free connective tissue grafts employing an envelope technique.