From the abstract:

"In the experiment, we vary the socio-economic status (SES) of the patient and whether a second opinion signal is sent. Furthermore, measures of market, practice and dentist characteristics are collected. We observe an overtreatment recommendation rate of 28 % and a striking heterogeneity in treatment recommendations. Furthermore, we find significantly less overtreatment recommendations for patients with higher SES compared to lower SES for standard visits, suggesting a complex role of patients' SES. Competition intensity, measured by dentist density, does not have a significant influence on overtreatment. Dentists with shorter waiting times are more likely to propose unnecessary treatment."