World traumatic dental injury prevalence and incidence, a meta-analysis-One billion living people have had traumatic dental injuries.

Traumatic dental injuries (TDIs) account for a considerable proportion of bodily injuries. Nevertheless, global TDI frequency is unknown, probably because TDI diagnosis is not standardized. This study estimated world TDI frequency. A literature search (publication years 1996-2016) was aimed at covering as many countries, communities, ethnic groups as possible, thus achieving high generalizability. In particular, non-specific keywords, no language restrictions, and large databanks were used. Observational studies reporting proportions of individuals with at least one TDI (prevalence) and who developed TDI (incidence rate) were considered. Prevalence rates to permanent dentition, primary dentition and in 12-year-olds, incidence rate to any tooth for any age, male-to-female prevalence ratio (PR) in 12-year-olds, with 95% confidence intervals (95 CIs), were extracted/calculated. Study quality, Z-score distribution, funnel plot symmetry analysis, between-study heterogeneity, sensitivity, and subgroup analyses were performed. Selected primary studies were 102 (permanent dentition; 268 755 individuals; median age, 13.8 years), 46 (primary dentition; 59 436 individuals; median age, 3.4 years), 42 (12-year-olds; 33 829 individuals), 11 (incidence rate; 233 480 person-years; median age, 7.8 years), and 31 (PR; 16 003 males, 16 006 females). World TDI frequency resulted as follows: permanent dentition prevalence 15.2% (95 CI, 13.0%-17.4%); primary dentition prevalence 22.7% (95 CI, 17.3%-28.7%); 12-year-olds prevalence 18.1% (95 CI, 15.3%-21.0%); incidence rate, 2.82 (95 CI, 2.28%-3.42%) per 100 person-years; PR, 1.43 (95 CI, 1.34%-1.52%). Differences between WHO Regions were found. This study shows that more than one billion living people have had TDI. TDI is a neglected condition which could rank fifth if it was included in the list of the world's most frequent acute/chronic diseases and injuries.