An oily Calcium Hydroxyde suspension (Osteoinductal®, Osteoinductal GmbH., München, Germany) was documented to induce bone regeneration in closed defects. Combined with a bone replacement material, the suspension produced statistically significant changes of the PD and CAL. The aim of this study is to evaluate the effect of Osteoinductal® alone in the treatment of deep intrabony defects, when compared to access flap (AF) surgery alone. 30 patients with one intrabony defect each were randomly treated with either AF+Osteoinductal® (test) or AF alone (control). The parameters evaluated at baseline and six months after surgery were: PI, BOP, PD, GR, CAL. Postsurgical care - administration of antibiotica (Amoxicillin 3x500 mg/die one week, 0.2% Chlorhexidine rinses twice daily for two weeks. Statistical analysis - the Wilcoxon paired test for evaluation of the changes from baseline to six months, and the Mann-Whitney U independent test for comparisons between the groups. At six months, measurements revealed in the test group a reduction in mean PD from 8.60 ± 2.06 mm to 3.27 ± 1.39 (p Keywords: oily calcium hydroxide suspension, intrabony defects