SCINTIGRAPHIC EVALUATION OF HEALING RESPONSE AFTER HETEROGRAFT USAGE FOR ALVEOLAR EXTRACTION CAVITY

Objective. Reconstruction of bone defects remains an important problem in oral and maxillofacial surgery. Restoration of defect sites with V arious grafting materials is a valuable approach to the solution of th is problem. The aim of this study was to evaluate the effects of the u se of heterografts on osteoblastic activity by means of a radionuclide technique. Study design. The postextraction alveolar cavities of impa cted mandibular third molars on 22 patients were used as a healing mod el for this study. Granulated freeze-dried heterograft material of bov ine origin was used on 11 patients; the other 11 patients constituted a control group. On each patient, three-phase bone scans were performe d on postoperative days 7 and 28. Results. Although dynamic and blood pool studies showed similar patterns with respect to the mean values o f asymmetry ratios of operation sites to the contralateral sides for t he 7th- and 28th-day scans, static-phase bone scans revealed that heal ing response through osteoinduction was more prominent in the study gr oup than in the control group. A significant increase in the mean Valu e of the ratio from the first scan to the second was observed on stati c images in the study group (first scan, 1.6 +/- 0.2; second scan, 2.0 +/- 0.5; p < 0.05). However,the same ratio failed to show any signifi cant change in the control group (first scan, 1.5 +/- 0.2; second scan , 1.5 +/- 0.3; p > 0.05). Conclusion. Static-phase bone scintigraphy s howed that when freeze-dried heterograft material is used to fill alve olar extraction cavities, it stimulates osteoblastic activity which in turn leads to acceleration of the healing process and helps to mainta in the linearity of bony structure. Moreover, radionuclide study can b e used to evaluate the viability of freeze-dried heterografts in the 4 th postoperative week, at which time no additional increase in perfusi on resulting from surgical trauma was found in our series.