The oily Calcium Hydroxide suspension Osteoinductal ® has been documented clinically and histologically to enhance the bone regeneration in closed bone defects and to stimulate the periodontal regeneration in intrabony defects. So far, there is only one controlled clinical study to compare the effect of Osteoinductal® with the effect of the enamel matrix protein derivative Emdogain® in treating deep intrabony defects, at six months after the surgery.Aim of the study was to compare at 12 months after the surgery the treatment of deep intrabony defects with Osteoinductal®, (Osteoinductal GmbH, München, Germany) to the treatment with the enamel matrix protein derivative Emdogain® (Straumann AG, Waldenburg, Switzerland).Seventeen healthy patients, displaying a total of thirty-six intrabony defects, were randomly treated either with Osteoinductal® (test) or with Emdogain®(control). Soft tissue measurements were made at baseline and 6 months following the therapy. No differences in any of the investigated parameters were observed at baseline between the two groups.No adverse healing response was observed in any of the patients. At 12 months after the therapy, the sites treated with Osteoinductal® showed a reduction in probing pocket depth (PPD) from 8.25±1.84 mm to 3.69±0.95 mm and a change in clinical attachment level (CAL) from 9.56±1.82 mm to 5.31±1.78 mm (p=0.001). In the group treated with Emdogain®, the PPD was reduced from 7.85±1.95 mm to 3.65±1.23 mm and the CAL changed from 8.35±2.28 mm to 5.05±1.76 mm (p Keywords: intrabony periodontal defects, oily calcium hydroxide suspension, enamel matrix proteins