There is a well-established link between oral pathology and eating disorders in the presence of self-induced vomiting. There is less information concerning this relationship in the absence of self-induced vomiting, in spite of risk factors such as psychotropic-induced dry mouth, nutritional deficiency or acidic diet.

To determine the association between eating disorder and poor oral health, including any difference between patients with and without self-induced vomiting.

A systematic search was made of Medline, PsycINFO, EMBASE and article bibliographies. Outcomes were dental erosion, salivary gland function and the mean number of decayed, missing and filled teeth or surfaces (DMFT/S).

Ten studies had sufficient data for a random effects meta-analysis (psychiatric patients n = 556, controls n = 556). Patients with an eating disorder had five times the odds of dental erosion compared with controls (95% CI 3.31–7.58); odds were highest in those with self-induced vomiting (odds ratio (OR) = 7.32). Patients also had significantly higher DMFS scores (mean difference 3.07, 95% CI 0.66–5.48) and reduced salivary flow (OR = 2.24, 95% CI 1.44–3.51).

These findings highlight the importance of collaboration between dental and medical practitioners. Dentists may be the first clinicians to suspect an eating disorder given patients' reluctance to present for psychiatric treatment, whereas mental health clinicians should be aware of the oral consequences of inappropriate diet, psychotropic medication and self-induced vomiting.

Psychiatric patients have increased comorbid physical illness. There is less information concerning dental disease in this population in spite of risk factors including diet and psychotropic side-effects (such as xerostomia).

To compare the oral health of people with severe mental illness with that of the general population.

A systematic search for studies from the past 20 years was conducted using Medline, PsycINFO, Embase and article bibliographies. Papers were independently assessed. The primary outcome was total tooth loss (edentulousness), the end-stage of both untreated caries and periodontal disease. We also assessed dental decay through standardised measures: the mean number of decayed, missing and filled teeth (DMFT) or surfaces (DMFS). For studies lacking a control group we used controls of similar ages from a community survey within 10 years of the study.

We identified 21 papers of which 14 had sufficient data (n = 2784 psychiatric patients) and suitable controls (n = 31 084) for a random effects meta-analysis. People with severe mental illness had 3.4 times the odds of having lost all their teeth than the general community (95% CI 1.6–7.2). They also had significantly higher scores for DMFT (mean difference 6.2, 95% CI 0.6–11.8) and DMFS (mean difference 14.6, 95% CI 4.1–25.1). Fluoridated water reduced the gap in oral health between psychiatric patients and the general population.

Psychiatric patients have not shared in the improving oral health of the general population. Management should include oral health assessment using standard checklists that can be completed by non-dental personnel. Interventions include oral hygiene and management of xerostomia.