Clinical and Radiographic Evaluation of Guided Tissue Regeneration With Radiation-sterilized Allogenic Bone Grafts or Xenogenic Grafts for the Treatment of Intrabony Defects in Aggressive Periodontitis

Inclusion Criteria: * Diagnosis of aggressive periodontitis in line with American Academy of Periodontology classification (Lang et al. 1999) * Familial aggregation (history of periodontitis in parents or siblings) * Presence of at least two teeth with probing pocket depth (PPD) ≥ 6mm and clinical attachment level (CAL) ≥ 5 mm associated with an intrabony defect of at least 3 mm as detected in diagnostic periapical radiographs * No furcation involvement of the teeth presenting the intraosseous defects * The width of keratinized tissue on the facial aspect of the selected teeth ≥ 2 mm Exclusion Criteria: * Full-mouth plaque index ≥ 20% (Ainamo \& Bay 1975) * Full-mouth sulcus bleeding index ≥ 15% (Mühlemann \& Son 1971) * Smoking more than 10 cigarettes/day * Systemic diseases with compromised healing potential of infectious diseases * Drugs affecting periodontal health / healing * Pregnant and lactating females * Previous periodontal surgery in the area