The mouth accounts for as little as 1% of the total body area but accounts for about 5% of bodily injuries.1 Data from the 2013 Children's Dental Health Survey conducted in England, Wales and Northern Ireland found an overall prevalence of TDI to permanent incisors of 9%.2 The aim of this review was to provide a reliable global estimate of the prevalence and incident rates of traumatic dental injuries (TDIs).

As the authors highlight the methodology for the Global Burden of Diseases (GBD) studies included data from disease registries, population surveys and healthcare facility data not merely epidemiological studies. A very broad search strategy has been used to identify potential studies for inclusion in the review but there are no disease registers or population surveys covering at least 10,000 people for TDI as recommended by the GBD. Consequently, epidemiological studies provide the majority of the information used for this review as healthcare facility data are considered unreliable so not considered.

The included studies covered all the WHO regions and 39 counties globally with Brazil, India and Turkey having the most representation. Study quality was assessed using a version of the Newcastle-Ottawa scale adapted for disease frequency studies. Quality was considered fair to good for scores ≥3, and all the included studies scoring between 3-5.

Overall a good methodological approach has been taken with this review with the authors discussing some of the main issues with this type of review. These not only concern the quality of the included primary studies but also their world representativeness. Diagnostic bias can be an issue in disease frequency studies but for TDI diagnosis for most injuries is straightforward. However, classification can be more problematic as the authors highlight the existence of fifty distinct classification systems,3 although almost 50% of the included studies used the Andreasen's/WHO classification.4

Despite a number of problems with the primary data which have been clearly discussed by the authors this well conducted review provided us with a main global prevalence estimate of TDI between 13.0%-17.4%. They were also able to estimate that males were 34%-52% more likely to develop TDI than females [prevalence ratio 1.43 (95% CI 1.34-1.52)]. In addition based on the world population in 2016 it estimates that approximately 900 million individuals had had at least one TDI of any kind to permanent teeth, pointing out that based on this data TDI would rank fifth if it were included in the list of the main chronic diseases and injuries by the GBD study 2015, after caries, headache, anaemia and hearing loss.5 This would place TDI above periodontal disease and severe tooth loss.

This review very helpfully highlights the often neglected issue of traumatic dental injuries and reinforces the need for appropriate prevention interventions emergency care and ongoing management programmes for this common problem.