Aim: The comparison of the effects of guided-tissue regeneration (GTR) using 2 different biodegradable barriers (polylactide acetyltributyl citrate. polydioxanon) in 3- and 2-wall intrabony defects. Method: The polydioxanon barrier is an experimental membrane for GTR therapy that consists of an continuous occlusive barrier that has a layer of slings on the side that is meant to face the: mucoperiosteal flap. 15 patients provided 15 pairs of similar contralateral periodontal defects: 12 predominantly 2-wall and 18 predominantly 3-wall intrabony defects, Each defect was randomly assigned to treatment with either polylactide acetyltributyl citrate (control [c]) or polydioxanon (test [t]) devices. At baseline and 6 months after surgery clinical measurements (PII. GI, PPD, PAL-V) were performed. Results: Barrier exposure was commonly observed in both groups (control/test): 5/4 after 7 days, 9/11 after 14 days and 11/12 after 28 days postsurgically. 4 weeks after surgery. 77% of all barriers were exposed to some extent. However, both treatments revealed a significant GI reduction (p<0.05), PPD reduction [-4.63+/-1.85 mm (t), -4.17+/-1.89 mm (c); p<0.001] and PAL-V gain [3.97+/-1.17 mm (t), 3.30 mm+/-1.40 (c); p<0.001] 6 months after surgery Regarding GI and PPD reduction as well as PAL-V gain, there were neither statistically significant nor clinically relevant differences between rest and control: similar clinical results were found 6 months after surgical treatment using both biodegradable barriers. Conclusions: Based on the results of the present study, the use of both biodegradable barriers in GTR therapy may be recommended.