The purpose of this study was to compare clinically and radiographically the results obtained following application of (1) commercially available demineralized freeze-dried bone allograft (DFDBA), (2) guided tissue regeneration (GTR) using a bioabsorbable polylactic acid softened with citric acid ester barrier, and (3) enamel matrix derivative gel (EMD), in the treatment of two- and three-walled intrabony defects. The study included 39 patients-12 in the DFDBA group, 12 in the GTR group, and 15 in the EMD group-each with one treated defect. Clinical measurements, Plaque Index, Gingival Index, probing depths, clinical attachment levels, and recession were comparable in the three groups at baseline. Measurements were repeated 12 months postoperative. Surgical measurements were also comparable at baseline among the groups. Radiographs were taken at baseline and 12 months later, and they were compared after reconstruction of the postoperative radiograph by a software program that produces geometric standardization. No significant differences in clinical results among the three groups were found. Radiographic assessment indicated a slight, nonsignificant difference in mean crestal bone resorption and defect fill between the groups. However, the mean improvement in intrabony depth was greater in the GTR and EMD groups than in the DFDBA group. The three regenerative procedures appeared to be equally effective in treating intrabony defects, with the exception of radiographic defect resolution, which was significantly greater in the GTR and EMD groups than in the DFDBA group.