The value of orthodontics: Do parents' willingness to pay values reflect the IOTN?

Given the limited evidence about the benefits of orthodontic treatment, many health care systems have rationed access to orthodontic care with the Index of Orthodontic Treatment Need (IOTN) being one tool used to attempt to allocate resources based on need. However, it is not clear whether patient and public valuations of different levels of need (as described by the IOTN) reflect the resource allocation decisions. The aim of this project was therefore to determine the values parents placed on correction of malocclusions at different IOTN levels using the willingness to pay (WTP) technique.

401 parents of children attending hospital-based orthodontic clinics in the North of England were recruited to complete a questionnaire eliciting WTP for the correction of seven malocclusions with different IOTN scores. In addition demographic and orthodontic history characteristics were collected. Results were analysed with appropriate pairwise significance tests and regression.

A significant difference in WTP was noted between all the possible pairs of malocclusions with the exception of overjets with moderate versus great need of treatments. At moderate levels, correction of crowding was valued less than overjet but this was reversed at great need levels. Very little of the variance in WTP was explained by the variables collected. When looking at factors affecting percentage difference between values for different pairs of malocclusions, in general, no factors predicted the magnitude of difference.

Median valuations for correction of malocclusions vary significantly for different levels of need (as judged by IOTN), with increasing levels of need generating higher values. However, there was a limited effect of demographic or orthodontic characteristics on the magnitude of percentage difference in values for correcting malocclusions different levels of need.