Comparative analysis of apical root resorption induced by different intrusion mechanics: A scanning electron microscopy study

Root resorption is a frequent iatrogenic consequence of orthodontic tooth movement and this study aims to compare the extent of root resorption induced by different intrusion mechanics, including mini-screws, bite turbos and box loops, using scanning electron microscopy (SEM). The sample included 18 maxillary first premolars extracted from nine orthodontic patients undergoing first premolar extractions. Subjects were randomly assigned to three groups (n = 6 teeth per group). Following extraction, one-third of the root was embedded in acrylic, while epoxy resin replicas of the apical two-thirds were prepared using silicone impressions. The samples were electroplated with silver and examined under SEM (JEOL Ltd., Tokyo, Japan) at 20 kV, with magnifications ranging from x35 to x1000. Within the study limitations, mini-screws and turbos produced more pronounced root resorption than box loop mechanics.