Fig. 5

Frontier analysis based on SDI and ASRs of the caries of permanent teeth in 2021. The frontier is delineated in solid black color; countries and territories are represented as dots. The top 15 countries with the largest effective difference (largest ASRs gap from the frontier) are labeled in black; examples of frontier countries with low SDI (< 0.5) and low effective difference are labeled in blue, and examples of countries and territories with high SDI (> 0.85) and relatively high effective difference for their level of development are labeled in red. Red dots indicate an increase in age-standardized ASRs from 1990 to 2021; blue dots indicate a decrease in ASRs between 1990 and 2021. Abbreviations: ASRs: Age-Standardized Rates; SDI: Socio-demographic index