The purpose of the study is to compare two methods for providing brief dental office-based interventions designed to help patients quit either cigarette smoking or smokeless tobacco use, and to compare these two dental office-based interventions with usual care. This trial will evaluate the effectiveness of a unique combination of dental office intervention plus referral to the telephone help line, both of which have been demonstrated to be effective interventions for tobacco cessation. The integration of two lines of research—dental office interventions and telephone help line effectiveness—led us to propose this clinical trial as a more efficient and disseminable model of both training and practice.