It has been concluded that available evidence suggests that behavioral interventions for tobacco cessation conducted by oral health professionals incorporating an oral examination component in the dental office or community setting may increase tobacco abstinence rates among both cigarette smokers and smokeless tobacco users (Cochrane Database Syst Rev.6:CD005084.) However, efficacy of tobacco cessation for oral diseases by oral health professionals are not elucidated. There are few studies on tobacco cessation intervention by dentists but none in terms of reduction of oral diseases or further disease prevention. Association for the Japanese Academy of Maxillofacial Implants, Association for the Japanese Society of Oral and Maxillofacial Surgeons, Association for the Japanese Society of Oral Implantology, Japanese Society of Oral Medicine, Japanese Society of Periodontology, Japanese Academy of Clinical Periodontology, Japanese Society for Oral Health, Japanese Society of Dentistry for Medically Compromised Patient and Japanese Society of Oral Oncology conduct a study to verify the efficacy of tobacco cessation in patients with oral diseases; periodontitis, dental implant and oral mucosal diseases by a multicenter prospective trial.