Authors’ response

Abstract

We thank the readers for their interest in the study and their letter. Our report was part of a dissertation project1Oh E. Upper cervical spine morphology in association with craniofacial morphology and jaw growth in children with class II and class III malocclusions. University of Copenhagen, Copenhagen2020Google Scholar together with other studies.2Oh E. Ahn S.J. Sonnesen L. Ethnic differences in craniofacial and upper spine morphology in children with skeletal class II malocclusion.Angle Orthod. 2018; 88: 283-291Crossref PubMed Scopus (17) Google Scholar, 3Oh E. Ahn S.J. Sonnesen L. Ethnic differences in craniofacial and upper spine morphology between European and Asian children with skeletal class III malocclusion.Am J Orthod Dentofacial Orthop. 2019; 156: 502-511Abstract Full Text Full Text PDF PubMed Scopus (6) Google Scholar, 4Oh E. Ahn S.J. Sonnesen L. Evaluation of growth changes induced by functional appliances in children with Class II malocclusion: superimposition of lateral cephalograms on stable structures.Korean J Orthod. 2020; 50: 170-180Crossref PubMed Scopus (6) Google Scholar Children were systematically collected for the series of studies, and ethical approval was received for the entire project. The present study included children with Class II malocclusion treated with 2 functional appliance types: combined high-pull headgear–Teuscher activator (Z-activator) and modified Andresen activator (E-activator) without a headgear. We used a standardization edge-to-edge bite registration protocol for both E- and Z-activators. Less vertical activation was introduced to minimize the rotation effects or tipping effect of teeth. In the previous article,4Oh E. Ahn S.J. Sonnesen L. Evaluation of growth changes induced by functional appliances in children with Class II malocclusion: superimposition of lateral cephalograms on stable structures.Korean J Orthod. 2020; 50: 170-180Crossref PubMed Scopus (6) Google Scholar the Z-activator group showed more retruded mandible, whereas the E-activator group presented more hypodivergent jaws than the matched control group at baseline. These differences correspond to the indications of the 2 appliances.5Teuscher U. A growth-related concept for skeletal Class II treatment.Am J Orthod. 1978; 74: 258-275Abstract Full Text PDF PubMed Scopus (101) Google Scholar However, skeletal changes induced by the 2 functional appliances were similar on a short-term and long-term basis. Therefore, children treated with the 2 appliances were pulled in the present study, and possible effects of the appliance type were statistically adjusted. Regarding the blinding, upper spine morphology and craniofacial characteristics were evaluated independently, and the observers were blinded to patients’ data in the present study. Morphologic deviations in the upper spine were evaluated by the 2 authors in all lateral cephalograms, and craniofacial characteristics and skeletal maturation were analyzed by 1 author. Twenty-five randomly selected lateral cephalograms were remeasured after 1 month to evaluate the reliability. Pertaining to the last point, evaluating the mandibular growth peak and skeletal maturation stage is critical when treating growing children with Class II malocclusion. In the present study, skeletal maturation was measured at pretreatment; postfunctional appliance; and >1-year retention after the functional appliance treatment at postpuberty, followed either with or without fixed appliances (T3), and the possible effect of the treatment timing was statistically adjusted. To eliminate bias caused by remaining growth in long-term treatment effect, children who have reached the postpubertal stage at T3 (cervical stage [CS]5-CS6) were included in the present study. In contrast, others with CS1-CS4 at T3 were excluded. We thank you again for the opportunity to answer these queries and share them with other readers. Functional appliance treatment in children with morphologic deviations in the upper spineAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 160Issue 3PreviewWe read with great interest the article by Oh et al (Oh E, Ahn S-J, Sonnesen L. Treatment effects of functional appliances in children with Class II malocclusion with and without morphologic deviations in the upper spine. Am J Orthod Dentofacial Orthop. Epub 2021 Apr 19). We appreciate and thank the authors for this interesting study on functional appliance therapy. However, we would like further clarification regarding some aspects of the study. Full-Text PDF