Background and aimsSubstance use disorders are associated commonly with comorbid physical illness. There are fewer data on dental disease in these conditions, in spite of high rates of dry mouth (xerostomia), as well as the associated indirect or life-style effects such as poverty and lack of access to care. We compared the oral health of people with substance use disorders (SUDs) with non-using controls. MethodThis was a systematic search for studies from the last 35years of the oral health of people reporting SUDs. We used MEDLINE, PsycInfo, OVID, Google Scholar, EMBASE and article bibliographies. Results were compared with the general population. Oral health was assessed in terms of dental caries and periodontal disease using the following standardized measures: the mean number of decayed, missing and filled teeth (DMFT) or surfaces (DMFS) and probing pocket depth. Non-carious tooth loss was assessed clinically. ResultsWe identified 28 studies that had sufficient data for a meta-analysis, comprising 4086 SU patients and 28031 controls. People with SUD had significantly higher mean scores for DMFT [mean difference=5.15, 95% confidence interval (CI)=2.61-7.69 and DMFS (mean difference=17.83, 95% CI=6.85-28.8]. They had more decayed teeth but fewer restorations, indicating reduced access to dental care. Patients with SUD also exhibited greater tooth loss, non-carious tooth loss and destructive periodontal disease compared to controls. ConclusionPatients with substance use disorders have greater and more severe dental caries and periodontal disease than the general population, but are less likely to have received dental care.