Journal of Dental Research 2015, Vol. 94(5) 650–658 © International & American Associations for Dental Research 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/0022034515573272 jdr.sagepub.com Clinical Review Introduction Dental caries manifests as a continuum of disease states of increasing severity and tooth destruction, ranging from sub- clinical changes to lesions with dentinal involvement (Featherstone 2004; Kidd and Fejerskov 2004). The initial stages of caries are asymptomatic, with symptoms starting after the carious lesion has progressed into dentine (Selwitz et al. 2007). The current standard for caries detection in epide- miologic surveys in most countries is the World Health Organization (WHO; 1997, 2013) criteria, which measure car- ies at cavitation level. Common caries indices measure past and present disease experience. Caries experience reflects lifetime prevalence and, though important to understand the natural history of the dis- ease, gives no information on levels of current active disease, which is arguably more important for the assessment of disease burden and planning dental care services. Current methods to assess disease burden are based on disability (Kassebaum et al. 2014a). The rational is the assumption that treated diseases do not cause burden and that past caries experience (DMFT) reflects both treated and untreated caries. Despite this impor- tant distinction, to date most reviews on caries epidemiology have focused only on caries experience (WHO 2003; Marthaler 2004; Thomson 2004; Griffin et al. 2005; Bagramian et al. 2009). Although it is accepted that lifetime prevalence of den- tal caries experience measured by the DMF index has declined in the last 40 y in many developed countries (Marthaler 2004; Bernabé and Sheiham 2014) and that individuals are suscepti- ble to caries throughout life (Thomson 2004; Griffin et al. 2005; Broadbent et al. 2013), the epidemiology of untreated caries is not yet fully understood. The goal of the Global Burden of Disease (GBD) 2010 study has been to systematically produce comparable estimates of the burden of 291 diseases and injuries and their associated 1,160 sequelae from 1990 to 2010. A key aspect of the GBD study was to enforce consistency between disease estimates of mortality and other epidemiologic parameters (prevalence, 573272JDR XX X 10.1177/0022034515573272Journal of Dental ResearchGlobal Burden of Untreated Caries review-article 2015 1 Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA 2 Department of Anesthesiology and Pain Medicine, University of Washington and Seattle Children’s Hospital, Seattle, WA, USA 3 Division of Population and Patient Health, King’s College London Dental Institute, London, UK 4 Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK A supplemental appendix to this article is published electronically only at http://jdr.sagepub.com/supplemental. Corresponding Author: W. Marcenes, Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary, University of London, Turner Street, London E1 2AD, UK. Email: w.marcenes@qmul.ac.uk Global Burden of Untreated Caries: A Systematic Review and Metaregression N.J. Kassebaum 1,2 , E. Bernabé 3 , M. Dahiya 4 , B. Bhandari 4 , C.J.L. Murray 1 , and W. Marcenes 4 Abstract We aimed to consolidate all epidemiologic data about untreated caries and subsequently generate internally consistent prevalence and incidence estimates for all countries, 20 age groups, and both sexes for 1990 and 2010. The systematic search of the literature yielded 18,311 unique citations. After screening titles and abstracts, we excluded 10,461 citations as clearly irrelevant to this systematic review, leaving 1,682 for full-text review. Furthermore, 1,373 publications were excluded following the validity assessment. Overall, 192 studies of 1,502,260 children aged 1 to 14 y in 74 countries and 186 studies of 3,265,546 individuals aged 5 y or older in 67 countries were included in separate metaregressions for untreated caries in deciduous and permanent teeth, respectively, using modeling resources from the Global Burden of Disease 2010 study. In 2010, untreated caries in permanent teeth was the most prevalent condition worldwide, affecting 2.4 billion people, and untreated caries in deciduous teeth was the 10th-most prevalent condition, affecting 621 million children worldwide. The global age-standardized prevalence and incidence of untreated caries remained static between 1990 and 2010. There is evidence that the burden of untreated caries is shifting from children to adults, with 3 peaks in prevalence at ages 6, 25, and 70 y. Also, there were considerable variations in prevalence and incidence between regions and countries. Policy makers need to be aware of a predictable increasing burden of untreated caries due to population growth and longevity and a significant decrease in the prevalence of total tooth loss throughout the world from 1990 to 2010. Keywords: global health, decay, root caries, prevalence, incidence, epidemiology