Demographic characteristics of orthodontic practice sites in the United States

Few studies have addressed the demographic characteristics of dental-practice sites, including orthodontic practice sites. In this study, we investigated the demographic characteristics of orthodontic practice sites in the United States. Demographic data and orthodontic practices were organized by zip codes and analyzed with discriminant analysis. The demographic characteristics associated with zip codes that contained an orthodontic practice were determined vs those without an orthodontic practice. The resulting model correctly classified 90.3% of the 30,134 zip code areas, based on the presence or absence of an orthodontic practice. The variables most closely associated with a zip code containing an orthodontic practice included number of dental practices (general practice) and population size. Several variables related to the socioeconomic status of the area were also positively related to zip codes with an orthodontic practice. Further analysis indicated a positive relationship between the model's output and its ability to predict single vs several orthodontic practices in a zip code area. A practical method for assessing the relative merits of alternate site locations is also provided.