Fig. 2

Ranking levels of the external apical root resorption by Levander and Malmgren [10]. Grade 0: absence of root resorption; grade 1: mild resorption, root with its normal length, and only an irregular contour; grade 2: moderate resorption, small area of root loss with the apex exhibiting an almost straight contour; grade 3: accentuated resorption, loss of almost one third of root length; and grade 4: extreme resorption, loss of more than one third of the root length