Purpose: This study examined patterns of invasion of lower gingiva cancer into the mandible. Our goal was to clarify the most common routes for gingival squamous cell carcinoma to enter and spread within the mandible.
Patients and methods: The subjects were 176 patients with lower gingival squamous cell carcinoma who underwent mandibulectomy; all tumors were examined histopathologically. The method of mandibulectomy was decided on the basis of conventional plain radiographic and computed tomographic findings.
Results: The tumor extended to the periosteum in 33%, to the cortical bone in 23%, and to the bone marrow in 9% of the patients who underwent mandibular resection. The remaining 35% of our patients had no evidence of mandibular invasion.
Conclusion: The area of bone resorption on preoperative clinical and radiographic examinations often disagreed with the extent of mandibular invasion on histopathologic examination.