Authors’ response

Abstract

We thank the authors of this letter for their interest in our study. Regarding the rate of tooth movement, Table I reports the change from day 0 in the time-points that tooth movement was measured. As the measurements were performed every 4 weeks, the numbers reported in Table I corresponded to a rate of millimeters per month (day 0–day 28), millimeter per 2 months (day 0–day 56), and millimeter per 3 months (day 0–day 84), respectively. Dividing tooth movement into millimeters per day or millimeters per week would have given minuscule numbers that would be of no importance. We considered that reporting the numbers, as in Table I, was more meaningful for all involved in the clinical process, meaning treating clinicians and those receiving treatment. Regarding the second point, we agree this is a minor repetition. We could have included in 1 sentence that there was not any previous orthodontic treatment in the maxilla and overall. As far as the eligibility of the patients is concerned, extraction of maxillary first premolars was required as part of their orthodontic treatment irrespective of the underlying malocclusion. Researchers involved in clinical trials can appreciate the difficulties involved in patient selection and recruitment. It is thus obvious that it is not feasible to find and recruit patients with identical crowding, underlying malocclusion, skeletal pattern, etc. Extractions can also be part of various types of malocclusions of dental or skeletal origin, including patients who might require orthognathic surgery. By broadening the type of included malocclusion, the generalizability of our results is also broadened and applies to any case that might need canine retraction. The choice of mechanotherapy was completely standardized for all patients during the study. Patients agreed to participate in the study, with canine retraction being the first part of their treatment, and all other orthodontic issues were addressed at a second stage. It is reported in the Interventions section that leveling and alignment were performed before canine retraction and that day 0 was the day that canine retraction commenced. This means that all the potential confounders could not have affected mechanotherapy and rate of tooth movement during this 3-month trial. As mentioned above, leveling and alignment of the maxillary dentition was performed before canine retraction. Experienced clinicians are aware that, very often, the maxillary first molars are rotated, crowded, or even ectopic. As a result, if these teeth are not leveled and aligned, it is impossible to insert working stainless-steel wires in their tubes when using the straight-wire technique. It goes without saying that sliding mechanics for extraction space closure are performed in stainless-steel wires, and all units involved (active and reactive) have to be effectively engaged to the working wire. We also know that increasing the number of teeth in the reactive unit increases its anchorage capability.1Mistry D. Dalci O. Papageorgiou S.N. Darendeliler M.A. Papadopoulou A.K. The effects of a clinically feasible application of low-level laser therapy on the rate of orthodontic tooth movement: a triple-blind, split-mouth, randomized controlled trial.Am J Orthod Dentofacial Orthop. 2020; 157: 444-453Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar,2Proffit W.R. Fields Jr., H.W. Larson B.E. Sarver D.M. Anchorage and its control.Contemporary Orthodontics. 6th ed. Elsevier, New York2019: 265-267Google Scholar By adding the second molars to the reactive unit, stabilizing them with a Nance-transpalatal arch, and ligating together second molars, first molars and second premolars on each side, we aimed to preserve anchorage for patients who required this for their second stage of treatment while simultaneously allowing for unimpeded leveling and alignment of the first molars. Another option would have been to use temporary anchorage devices (TADs) to reinforce anchorage. Nevertheless, TAD success can be device-, patient-, site-, and technique-sensitive, with success rates ranging between 56% and 100%.3Crismani A.G. Bertl M.H. Celar A.G. Bantleon H.P. Burstone C.J. Miniscrews in orthodontic treatment: review and analysis of published clinical trials.Am J Orthod Dentofacial Orthop. 2010; 137: 108-113Abstract Full Text Full Text PDF PubMed Scopus (110) Google Scholar, 4Meursinge Reynders R.A. Ronchi L. Ladu L. van Etten-Jamaludin F. Bipat S. Insertion torque and success of orthodontic mini-implants: a systematic review.Am J Orthod Dentofacial Orthop. 2012; 142: 596-614.e5Abstract Full Text Full Text PDF PubMed Scopus (67) Google Scholar, 5Papadopoulos M.A. Papageorgiou S.N. Zogakis I.P. Clinical effectiveness of orthodontic miniscrew implants: a meta-analysis.J Dent Res. 2011; 90: 969-976Crossref PubMed Scopus (76) Google Scholar, 6Papageorgiou S.N. Zogakis I.P. Papadopoulos M.A. Failure rates and associated risk factors of orthodontic miniscrew implants: a meta-analysis.Am J Orthod Dentofacial Orthop. 2012; 142: 577-595.e7Abstract Full Text Full Text PDF PubMed Scopus (174) Google Scholar In addition, TAD complications such as damage to the periodontal ligament, cementum, or dentine are usually of minor importance but can still sometimes lead to pulp necrosis or irreparable damage to the underlying tissues.7Lv Y. Zhang Z. Su Y. Yuan P. Ma W. Huang W. et al.Healing of root and surrounding periodontium after root damage with miniscrew implants: a histomorphologic study in dogs.Clin Oral Investig. 2018; 22: 1103-1111Crossref PubMed Scopus (5) Google Scholar,8Rossi-Fedele G. Franciscatto G.J. Marshall G. Gomes M.S. Doğramacı E.J. Endodontic complications associated with orthodontic temporary anchorage devices: a systematic review of human studies.Aust Endod J. 2020; 46: 115-122Crossref PubMed Scopus (4) Google Scholar Considering all the above, possible TAD complications would delay treatment and possibly cause harm when placed into crowded interradicular spaces. This issue would have introduced another unpredictable factor that could have violated the standardization of treatment. During clinical decision-making, the design of the appliances is defined by treating clinicians and not vice versa. Although a Nance-transpalatal arch is commonly used on the maxillary first molars, it is neither the device nor the usual applications that dictate where an appliance will be anchored. Subsequently, it was decided to apply dentally supported anchorage and cement the Nance-transpalatal arch to the second molars to increase the size of the reactive unit, level and align the first molars and have a more predictable anchorage modality. Regarding point 5 by the authors, it was mentioned in the Interventions section that “Occlusal stops were placed on the first molars to prevent any interferences during retraction.” This mild bite raising was applied to all patients, even to those who might not obviously need it for standardization reasons. When we refer to “interferences,” this also includes any cross-bite present on the path of canine retraction like the one shown in the illustrated case. Finally, the illustrated case was treated with extractions in the mandibular arch, although this was irrelevant to the present study's objectives. For consistency and hospital clinic management reasons, maxillary fixed appliances were first bonded for all patients for the study's duration, and after the study completion, all further necessary procedures were performed for completion of their treatment on the basis of an individualized plan and to the best of patient care. Low-level laser therapyAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 159Issue 4PreviewWe read the article on low-level laser therapy in the April 2020 issue with great interest (Mistry D, Dalci O, Papageorgiou SN, Darendeliler MA, Papadopoulou AK. The effects of a clinically feasible application of low-level laser therapy on the rate of orthodontic tooth movement: a triple-blind, split-mouth, randomized controlled trial. Am J Orthod Dentofacial Orthop 2020;157:444-53). Full-Text PDF