Erratum to “A clinical risk prediction model of orthodontic-induced external apical root resorption” [Rev Port Estomatol Med Dent Cir Maxilofac. 2014;55(2):66–72]

In the electronic and the print version of this article, on page 68, where it reads “CR2 = R2/CF”, it should read:

“CR2 = R2 × CF”.

The publisher would like to apologise for any inconvenience caused.