The aim of the present study was to evaluate, over a period of 1 y, 3 different surgical methods for the treatment of periodontal bone defects.Thirty-six infrabone defects, at least 4 mm in depth, in non-smokers were enrolled in the study. Of these, 12 were treated with guided tissue regeneration (GTR) using a resorbable membrane with collagen, 12 with enamel matrix derivative (EMD) gel and 12 with a modified Widman flap (MWF). The pocket depth, attachment loss and gingival recession both before commencement of therapy and after an interval of 1 y are reported.The reduction in pocket depth was 4 mm, 4.4 mm, and 4.5 mm, respectively, for the control group, GTR group and EMD group. The attachment gain for the respective treatments was: MWF, 2 mm; GTR, 2.8 mm; EMD, 2.9 mm. Gingival recession was: MWF, 1.8 mm; GTR, 1.5 mm; EMD, 1.1 mm.These findings show the efficacy of the 3 methods in the treatment of bone defects, but none of the 3 emerges as being statistically superior to the others 2.