HISTOMORPHOMETRIC ANALYSIS OF OSTEOCLASTIC RESORPTION IN BONE DIRECTLY INVADED BY GINGIVAL SQUAMOUS-CELL CARCINOMA

Whole frontal sections of the mandibular bone from 18 patients with gi ngival squamous cell carcinoma showing direct bone invasion were prepa red for histometrical analysis by a non-decalcified grinding method. T he osteoclast cytoplasmic area in tumor sites was larger and its relat ive frequency distribution was broader than that of osteoclasts in non -tumor sites. The index of bone resorption was significantly increased , while that of bone formation was decreased, in the tumor sites compa red to the non-tumor sites (P<0.01). In the tumor sites, the indices o f bone resorption and formation in the group showing greatest chemothe rapy and radiation therapy effects (CRE) were significantly different from those in the group with low CRE (P<0.01). A history of irradiatio n therapy was associated with significantly decreased bone resorption (P<0.05).