Inequality in State-based Distribution of U.S. Pediatric Dentists

Objectives: To determine evenness in state-based distribution of pediatric dentists relative to distribution of children across the United States
Methods: State-based distributions in the Year 2010 were obtained for pediatric dentists (Pediatr Dent 2015; 37:502-507), pediatricians (J Pediatr 2011; 159:1036-1040), and children less than 18 years of age (Census 2010, U.S. Census Bureau). State-based pediatrician data was reference for assessment of pediatric dentist distribution in the United States. State-based percentages for pediatric dentists, pediatricians, and children were computed to determine their proportions in the nation. For plotting of Lorenz curves, states were ranked in ascending order of state-based pediatric dentist ratios as well as pediatrician ratios per 100,000 children. State-based distributions of pediatric dentists and pediatricians were plotted relative to the line of equality (perfect distribution) for determination of Lorenz curves (Pediatrics 1997; 100:172-179). Cumulative state-based percentages of children were plotted on the x-axis. Cumulative state-based percentages of pediatric dentists and pediatricians were plotted on the y-axis commencing with the state with the lowest ratio per 100,000 children. Trapezoid rule was used to compute corresponding Gini indices for the two Lorenz curves and thereby quantify inequality in distributions of pediatric dentists and pediatricians relative to distribution of children across the United States.
Results: There were 12 times as many pediatricians (n=52,673) than pediatric dentists (n=4,453). There was uneven state-based distribution of pediatric dentists (Gini index=0.1398) relative to distribution of children but the inequality was less than that for pediatricians (Gini index=0.1511).
Conclusions: Relative to the state-based distribution of children in the United States, pediatric dentists were more evenly distributed than pediatricians.