Authors' response

Abstract

We greatly appreciate the clinical interest in our recently published article. We believe that an evidence-based orthodontic practice should be our goal and we appreciate the opportunity to clarify some points of our work. We want to point out some aspects regarding Dr Gopalakrishnan's concern on the possibility that the outcome variables evaluated in the study (changes in position and inclination of the maxillary incisors) may be influenced by the magnitude and duration of force exerted by the nickel-titanium open-coil springs. First, the possibility of a greater space requirement to align the maxillary incisors was controlled as an inclusion criterion; specifically, patients included in this study did not require a space >3 mm (minor needs). Therefore, a large protrusion of incisors should not be expected after orthodontic treatment because we tried to recover only the space of eruption for the impacted canines, which was almost maintained by the presence of the deciduous canines. In addition, all patients were diagnosed as having Class I malocclusion with adequate intercuspation and without great space requirements. For this reason, all patients were treated without premolar extractions. Second, initial diagnosis and planning of approximately how many millimeters the maxillary incisors may protrude after the impacted canines have been placed in their final position in the dental arch should be routinely performed, even more in patients with a maxillary impacted canine who do not require premolar extractions. These steps should be taken considering the tooth's greater width regarding deciduous canines and with an emphasis on bilateral canine impaction. It has been reported that the impacted canines are associated with a certain degree of retroclined incisors that should be corrected at the time of the canine traction.1Baratieri C. Canongia A.C. Bolognese A.M. Relationship between maxillary canine intra-alveolar position and maxillary incisor angulation: a cone beam computed tomography study.Braz Dent J. 2011; 22: 146-150Crossref PubMed Google Scholar, 2Alessandri Bonetti G. Incerti Parenti S. De Rinaldis S. Marini I. Association between the inclination of the lateral incisors and the position of the erupting canines on panoramic radiographs.Acta Odontol Scand. 2011; 69: 222-228Crossref PubMed Scopus (7) Google Scholar, 3Alqerban A. Jacobs R. Fieuws S. Willems G. Radiographic predictors for maxillary canine impaction.Am J Orthod Dentofacial Orthop. 2015; 147: 345-354Abstract Full Text Full Text PDF PubMed Scopus (40) Google Scholar In our study, the patients did not have an initial diagnosis of dentoalveolar protrusion. Thus, some protrusion was acceptable. The necessary spaces for canine traction were prepared without the need of overcorrection because of the occlusal characteristics of the patients. Third, all patients were treated by the same orthodontist who was experienced in the traction of maxillary impacted canines. The treatment protocol was standardized and controlled, considering the individual characteristics of each patient, beginning with the traction after the canine crowns were separated from the roots of the maxillary incisors. When the required spaces were obtained, the traction was initiated. In cases of bilateral impaction, the traction was started simultaneously. The force exerted by the nickel-titanium open-coil springs to prepare the spaces ranged between 50 g of force and 100 g of force, and the duration of their active use was approximately 2 months, independently on the unilateral or bilateral condition.4Arriola-Guillén L.E. Ruíz-Mora G.A. Rodríguez-Cárdenas Y.A. Aliaga-Del Castillo A. Días-Da Silveira H.L. Root resorption of maxillary incisors after traction of unilateral vs bilateral impacted canines with reinforced anchorage.Am J Orthod Dentofacial Orthop. 2018; 154: 645-656Abstract Full Text Full Text PDF Scopus (11) Google Scholar, 5Arriola-Guillén L.E. Ruíz-Mora G.A. Rodríguez-Cárdenas Y.A. Aliaga-Del Castillo A. Boessio-Vizzotto M. Dias-Da Silveira H.L. Influence of impacted maxillary canine orthodontic traction complexity on root resorption of incisors: a retrospective longitudinal study.Am J Orthod Dentofacial Orthop. 2019; 155: 28-39Abstract Full Text Full Text PDF Scopus (14) Google Scholar, 6Arriola-Guillén L.E. Rodríguez-Cárdenas Y.A. Ruíz-Mora G.A. Aliaga-Del Castillo A. Schilling J. Dias-Da Silveira H.L. Three-dimensional evaluation of the root resorption of maxillary incisors after the orthodontic traction of bicortically impacted canines: case reports.Prog Orthod. 2019; 20: 13Crossref Scopus (4) Google Scholar, 7Rodríguez-Cárdenas Y.A. Ruíz-Mora G.A. Aliaga-Del Castillo A. Dias-Da Silveira H.L. Arriola-Guillén LE. Root and alveolar bone changes in first premolars adjacent to the traction of buccal versus palatal maxillary impacted canines.PLoS One. 2019; 14: e0226267Crossref Scopus (2) Google Scholar Finally, all of these controlled variables raise the possibility of associating the change in the maxillary incisor position and inclination after maxillary impacted canine traction. However, studies in human subjects cannot be adequately controlled, and some variables could influence the outcome variables. Therefore, more studies should be performed. We thank you for reading our article and for the opportunity to discuss the study further. Space requirement and force are important factors in incisor positionAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 157Issue 6PreviewI read with great interest the article on changes in maxillary incisor inclination and position in patients with impacted canines by Chávez-Alvarez et al (Chávez-Alvarez C, Arriola-Guillén LE, Rodríguez-Cárdenas YA, Ruíz-Mora GA, Fiori-Chincaro G, Dias-Da Silveira HL, et al. Changes in maxillary incisor inclination and position after traction of unilateral vs bilateral maxillary impacted canines in nonextraction treatment: A cone-beam computed tomography study. 2019;156:767-78) in the December 2019 issue. Full-Text PDF