CONCLUSION: Our results show that average and poor oral hygiene and inadequate dental status are independent risk factors for oral and oropharyngeal squamous cell carcinoma (OOSCC), irrespective of tobacco and alcohol consumption. OBJECTIVE: To evaluate a possible relationship between oral cancer, oral hygiene, dental status, oral mucosal lesions and some lifestyle factors in a population-based case-control study. MATERIAL AND METHODS: Between September 2000 and January 2004, 132/165 (80%) of all incident cases of OOSCC and 320/396 (81%) of the intended eligible matched controls participated in the study. Cases and controls were subjected to an identical oral examination. A standardized protocol specially designed for the study was used. RESULTS: After adjusting for tobacco and alcohol consumption, average oral hygiene (OR 2.0; 95% CI 1.1-3.6) and poor oral hygiene (OR 5.3; 95% CI 2.5-11.3) emerged as significant risk factors for OOSCC. More than 20 lost teeth (OR 3.4; 95% CI 1.4-8.5), >5 defective teeth (OR 3.1; 95% CI 1.2-8.2) and poorly fitting or defective complete dentures (OR 3.8; 95% CI 1.3-11.4) were significant risk factors. Regular dental check-ups were associated with a decreased risk of OOSCC (OR 0.4; 95% CI 0.2-0.6).