Mystery of apical root resorption

Abstract

In a July 2011 article, Bonetti et al1Bonetti G.A. Parenti S.I. Daprile G. Montevecchi M. Failure after closed traction of an unerupted maxillary permanent canine: diagnosis and treatment planning.Am J Orthod Dentofacial Orthop. 2011; 140: 121-125Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar 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.2Bonetti G.A. Zanarini M. Parenti S.I. Marini I. Gatto M.R. Preventive treatment of ectopically erupting maxillary permanent canines by extraction of deciduous canines and first molars: a randomized clinical trial.Am J Orthod Dentofacial Orthop. 2011; 139: 316-323Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar 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.3Kokich V.G. Orthodontic and nonorthodontic root resorption: their impact on clinical dental practice.J Dent Educ. 2008; 72: 895-902PubMed Google Scholar The connection between canine impaction and root resorption of the incisors is mentioned in the literature. According to Otto,4Otto R.L. Early and unusual incisor resorption due to impacted maxillary canines.Am J Orthod Dentofacial Orthop. 2003; 124: 446-449Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar 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.3Kokich V.G. Orthodontic and nonorthodontic root resorption: their impact on clinical dental practice.J Dent Educ. 2008; 72: 895-902PubMed Google Scholar Dermaut and Munck5Dermaut L.R. Munck A.D. Apical root resorption of upper incisors caused by intrusive tooth movement: a radiographic study.Am J Orthod Dentofacial Orthop. 1986; 90: 321-326Abstract Full Text PDF PubMed Scopus (122) Google Scholar 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. Failure after closed traction of an unerupted maxillary permanent canine: Diagnosis and treatment planningAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 140Issue 1PreviewThis report describes the treatment of a 13-year-old girl with unerupted maxillary permanent canines. It illustrates how recognizing an unexpected problem influenced the decision-making process. Despite 6 months of closed-eruption traction, the left canine had not erupted. However, the neighboring teeth were intruded, suggesting a diagnosis of canine ankylosis. When the site was surgically reopened, the wire chain used for the orthodontic traction appeared to be osseointegrated. It was renewed, and traction was applied for another 16 months, and the tooth was successfully brought into the arch. Full-Text PDF Author’s responseAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 141Issue 2PreviewI thank Dr Bai for his interest in our article, but I want to express a few concerns regarding his assertions. As reported on page 121, the article focused specifically on “an unexpected problem encountered during the treatment of an unerupted maxillary permanent canine” and not generally on the treatment of an unerupted maxillary permanent canine. Not even the different “ways to treat impacted canines” was part of the topic of this article. The real message from this clinical report is that, when failure of a closed traction occurs, not only tooth ankylosis, but also osseointegration of the wire chain should be considered as possible causative factors. Full-Text PDF