The patient sample used in the present study comprised 16 young individuals who were referred for treatment of advanced periodontal disease. Based upon the age of the patients and the location of the diseased sites, the patients were divided into 2 groups; a juvenile periodontitis group (JP) and a post-juvenile periodontitis group (post-JP). The patients in the JP group had periodontal lesions only at first molars and incisors. All 16 subjects were in excellent general health and none had been treated with antibiotics during a period of at least 12 months prior to the 1st examination. At a baseline examination and 6, 24 and 60 months after active therapy, the diseased sites were examined regarding plaque, gingivitis, probing pocket depths, probing attachment level, recession of the gingival margin and marginal alveolar bone level. Following a case presentation and instruction in proper oral hygiene measures, the 16 subjects were subjected to periodontal treatment, utilizing a split mouth design. By random selection, the diseased sites in one side of the jaws were treated by scaling and root planing in conjunction with a "modified Widman flap" procedure, while in the contralateral jaw quadrants treatment was restricted to scaling and root planing. During the 1st 6 months following active therapy, the patients were subjected to professional tooth cleaning once every 4 weeks. Subsequently, the interval between the recall appointment was 3 months. 2 years after treatment, this maintenance care program was terminated. A final examination was performed 5 years after therapy. None of the patients involved in the trial received antibiotic treatment during the 5 years of observation. The findings of the present study revealed that the response of the periodontal tissues to therapy, both in the JP and the post-JP group of patients, was almost identical to that found for similar types of treatment in patients with adult periodontitis. The re-examinations performed after 6, 24 and 60 months following active therapy of JP and post-JP lesions revealed that excision of the granulation tissue in conjunction with flap elevation did not enhance the degree of probing pocket depth reduction, probing attachment gain and bone fill that occurred following meticulous root surface instrumentation.