Study Variables

The main predictor was child's race, as reported by the child's primary caregiver. Children were classified as White or non-White (Black, Asian, American Indian, Alaskan Native, Hawaiian, Pacific Islander, other, missing).

The outcome variable was orthodontic service utilization (no/yes). This was defined through CDT code D8660, which indicates a claim submitted by a provider for orthodontic records between January 2012 and September 30, 2012. This 9-month window served as the baseline period and the latter date of this range was selected to allow children up to three months to initiate treatment after obtaining records. CDT codes of D8010-D8080 represented initiation of orthodontic treatment.¹⁵ Children with a code of D8660 followed by a code D8010-D8080 were classified as having utilized orthodontic services and remaining children were classified as not having utilized orthodontic services.

There were four additional study variables: gender (female/male), age (6-11 years or 12-19 years) calculated as of December 31, 2012, Hispanic ethnicity (caregiver reported as Hispanic or non-Hispanic), and preventive dental care use in 2012 (no/yes). Children with any of the following CDT codes were classified as having utilized preventive dental care in 2012: D1110-1120 (dental prophylaxis), D1206 or 1208 (topical fluoride treatment), D1330 (oral hygiene instructions), or D1351 (sealant application). Each variable was conceptualized as potential effect modifiers of race and were not part of the main effects model.