LAUSR

OBJECTIVES We aimed to systematically review and meta-analyze the global, super-regional, regional and national prevalence of molar-incisor-hypomineralization (MIH) and to determine the numbers of prevalent and incident cases on different spatial scales. The review was registered (PROSPERO CRD42017063842). SOURCES Five electronic databases (Medline, EMBASE, LILACS, Web of Science, Google Scholar) were searched systematically. STUDY SELECTION Observational studies on the prevalence of MIH were included and the prevalence on different spatial scales (global, super-regional, regional, national) synthesized using random-effects meta-analyses. The prevalence was then regressed on a large set of methodological, socioeconomic and environmental variables to estimate the global burden (incident and prevalent cases) of MIH. DATA Of 2239 identified studies, 99 studies on 113,144 participants from 43 countries were included. The meta-analysis yielded a mean (95% CI) prevalence of 13.1% (11.8-14.5%), with significant differences between super-regions, regions and countries. The number of prevalent cases in 2015 was estimated at 878 (791-971) million people, while the number of incident cases in 2016 was 17.5 (15.8-19.4) million. Of these, 27.4% (23.5-31.7%) (in mean, 240 million prevalent and 4.8 million incident cases, respectively) were or will be in need of therapy due to pain, hypersensitivity or posteruptive breakdown. Heavily populated countries contribute significantly to the burden of prevalent cases, while growing countries like India, but also Pakistan or Indonesia rank first with respect to the number of incident cases. CONCLUSIONS MIH is highly prevalent across the globe. Certain (mainly low- and middle income) countries shoulder the majority of this burden. Clinical significance The consistently high prevalence and the large proportion of cases in need of care should be considered by both clinicians in their daily practice and healthcare planners and policy makers.