(A) To assess the prevalence of suboptimal oral health in adults with SMI in studies published in 1971-2009; (B) To describe approaches that promote oral health among adults with SMI. A total of 57 randomized, quasi-randomized, cross-section, and cohort studies from samples of 38-4,769 mental health consumers are identified through database, journal, and Internet searches (Cochrane, FASTSTATS, PUBMED, WHO.int). Selected studies are inclusive for the sample, reported statistical power, and external validity. Oral health adverse outcomes (xerostomia, sialorrhoea, dental caries, extracted teeth, malocclusion, periodontal disease, edentulous, oral cancer) are considered as measurable outcomes. This review suggests a substantial prevalence of suboptimal oral health (61%) among individuals with serious mental illnesses. The following outcomes are mostly met: xerostomia, gross caries, decayed teeth, and periodontal disease. Poor oral hygiene, higher intake of carbonates, poor perception of oral health self-needs, length of psychotropic treatment, and less access to dental care determine suboptimal oral health among this population. Further replication of this research should generate gender-wise ethnic cohorts, including detailed observations of environmental factors, and medical problems that contribute to suboptimal oral health. This review highlights the importance of bridging dental health education to psychiatric rehabilitation programs.