Bone regeneration using bone substitutes and/or bone promoters have become a widely considered adjunct to surgical endodontic therapy. Numerous bone grafting materials claimed over the years to promote osseous healing of lesions of endodontic origin. An oily Calcium Hydroxide suspension (Osteoinductal®, Osteoinductal GmbH, Muenchen, Germany), clinically proven to reduce post-extraction pain, inflammation and bleeding, has been used in this preliminary controlled study to promote bone healing in surgically treated periapical lesions. 16 lesions with diameters varying between 7-20 mm were randomly treated either with apicoectomy, curettage and Osteoinductal® (treatment group), or with apicoectomy and curettage alone (control group). Standardized radiographs were taken before and two months after the surgery. The Osteoinductal® group displayed an excellent clinical healing. Evaluation was made on the radiographs at two months by using a computer-assisted densitometric method. Statistical analysis used the Mann-Whitney non-parametric test. Relative density between individual standard areas of sound bone and the periapical areas of surgically treated teeth varied between 50% and 108% within the Osteoinductal® group, with a mean value of 79 ± 19,7%, and between 64% and115% with a mean value of 89 ± 18,7% within the control group. The results show that the oily Calcium hydroxide suspension did not improve the relative bone density of surgically treated periapical lesions at two months, but the difference between the groups was not statistically significant. Results also indicate the limits of the densitometric analysis in groups with large dispersion of the values, and, subsequently, a strong dependence of the analysis on the initial size of the defect and on the number of cases. Keywords: periapical healing, densitometry, oily calcium hydroxide suspension