Sažetak Surgical treatment of periodontal lesions on 864 sites in 26 patients was assessed. The preoperative pocket depth was between 3.5 and 4.8 mm (pocket depth < 4 mm and > 4 mm), and the attachment level between 2.8 and 5.5 mm. The effectiveness of three flap procedures (modified Widman-flap, and apical flap with and without bone resection) was compared according to pocket reduction and gain in attachment on teeth with a plaque index of 0 or 1. In contrast to many reports available, special emphasis was given to outpatient treatment in the conditions of a dental office. The patients were only once instructed on dental hygiene, so there was no professional oral hygiene control.