In a July 2011 article, Bonetti et al reported on the treatment of an unerupted maxillary permanent canine. Canines play vital roles in both dentofacial esthetics and function. Canine impaction can lead to reduced arch length and internal or external apical root resorption.

Comprehensive ways to treat impacted canines are of great importance. In general, there are 2 conventional methods. One is extraction of the deciduous canines or concomitant extraction of the deciduous canines and first molars in the early or late mixed dentition. The other is surgical exposure followed by orthodontic traction in the permanent dentition.

The latter method was applied for the patient reported in the article, and the canine was successfully brought into occlusion. However, root resorption of the 4 maxillary incisors couldn’t be ignored and could be seen clearly in Figure 2 compared with the pretreatment panoramic radiograph.

Using the definition that “moderate to severe root resorption is typically described as a greater than 20 percent reduction in the original root length,” root resorption in this patient could be classified as moderate to severe.

The connection between canine impaction and root resorption of the incisors is mentioned in the literature. According to Otto, orthodontic correction of high maxillary canines has been associated with greater root resorption of adjacent incisors because of reciprocal intrusive forces. Root resorption occurs in response to compression of the periodontal ligament, which happens with the eruption of the maxillary canines. Dermaut and Munck also believed that intrusive movement and force can cause apical root resorption.

Did the authors consider the potential jeopardy when determining the patient’s treatment plan? When the side effects were considered, why did the authors decide to continue the procedure? Has the mobility of the incisors been examined? Have the authors taken any preventive or interceptive measurements, such as a series of periapical radiographs, to monitor this problem? In the authors’ viewpoint, was the traction of the impacted canine the cause of the apical root resorption of the maxillary incisors? We would like the authors to answer these questions regarding root resorption.