X-rays should be performed only when clinically appropriate, but a new study finds that dentists often take money into consideration.
Dental X-rays are the most common form of X-ray radiation most people receive. Though they are relatively common, they are a known carcinogen. To minimize exposure, X-rays are only to be given when clinically necessary. But what happens in a fee-for-service model, where more X-rays can turn into more profits?
Researchers in the United Kingdom asked this question, and came to the conclusion that the promise of more money is a factor in the number of X-rays performed. Their study, published in the Journal of Health Economics, shows that “there are significant increases in X-rays when dentists receive fee-for-service rather than salary payments and when patients are made exempt from payment.”
To find their answer, researchers examined data from the NHS in Scotland. In Scotland, dentists working in the public sector are either reimbursed in a fee-for-service model or are salaried, with income independent of services performed. Patients receiving care from public dentists are either exempt from charges or if non-exempt pay 80 percent of the treatment fee up to a certain amount.
Using claim data from 1998 to 2007 - about 1.2 million total claims covering over 200,000 patients and 3,144 dentists - the researchers discovered differences between the number of x-rays given by salaried dentists and fee-for-service dentists.
During that long period, some of those dentists switched between salaried and fee-for-service payment models, giving an even clearer picture of the number of X-rays given under each model. Dentists who switched from salary to fee-for-service were 6.3 percent more likely to give an X-ray after the change. For patients making the change from non-exempt to exempt, the likelihood of receiving an X-ray increased by 3.4 percent.
Overall, exempt patients receiving treatment from a fee-for-service dentist were 4.1 percent more likely to receive an X-ray than a non-exempt patient receiving treatment from a salaried dentist.
Also of interest, older dentists were more likely to give x-rays, while older patients were less likely to receive an X-ray.
Co-author Martin Chalkley of the Centre for Health Economics at the University of York says that “Our study clearly shows that a potentially harmful treatment is being given in varying quantities according to how dentists are paid for it and we believe this is a genuine cause for concern. Dental X-rays deliver a very small dose of radiation, but there are no safe levels - every last bit of radiation is potentially harmful. Each dentist has to weigh up the risks versus the benefits before they take the decision to X-ray and our findings indicate that this calculation is being distorted by financial incentives.”
“First do no harm – The impact of financial incentives on dental X-rays.” Published in the Journal of Health Economics DOI: 10.1016/j.jhealeco.2017.12.005