Table 4.

Descriptive characteristics of orthodontic DSAs grouped by quartiles of utilization rates

	Low utilization rates	Medium low utilization rates	Medium high utilization rates	High utilization rates
Mean utilization rate per 100 Medicaid enrollees	0.66	1.58	3.40	5.81
Number of service areas in quartile	5	5	4	5
Mean population density (per square mile)	622.4	104.8	50.1	40.1
Mean geographic area (square miles)	566.0	2628.0	3344.1	5376.9
Mean total population, 2010 (n)	136,056	138,118	159,356	204,083
White population (%)	46.2	55.7	68.9	63.1
Black population (%)	13.3	4.6	4.9	5.7
Hispanic population (%)	10.2	11.5	4.4	10.1
Mean travel distance to orthodontist (miles)	8.8	26.8	23.4	28.6