Rapid maxillary expansion, with traditional or novel expander?

Abstract

Rapid maxillary expansion is widely used to treat maxillary constriction.1Lagravere M.O. Major P.W. Flores-Mir C. Long-term dental arch changes after rapid maxillary expansion treatment: a systematic review.Angle Orthod. 2005; 75: 155-161PubMed Google Scholar Traditional maxillary expanders such as the hyrax have been proved to be efficient. In contrast, novel ones have been proposed, such as the maxillary expander with differential opening (EDO), aiming to promote greater expansion,2Garib D. Lauris R.C. Calil L.R. Alves A.C. Janson G. De Almeida A.M. et al.Dentoskeletal outcomes of a rapid maxillary expander with differential opening in patients with bilateral cleft lip and palate: a prospective clinical trial.Am J Orthod Dentofacial Orthop. 2016; 150: 564-574Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar which is why we read the article by Arthur César de Medeiros Alves et al with great interest (Alves ACM, Janson G, McNamara JA, Jr, et al. Maxillary expander with differential opening vs Hyrax expander: A randomized clinical trial. Am J Orthod Dentofacial Orthop 2020;157:7-18). From this article, we learned a lot about maxillary expander with differential opening and its impressive performance on dentoskeletal changes. However, we still have a few questions. First, the eligibility criteria included patients of both sexes in the mixed dentition stage, diagnosed as maxillary constriction and Class I or Class II sagittal relationships. However, the authors did not illustrate the diagnostic criteria or basis of maxillary constriction, which is the indication of applying the maxillary expanding treatment. Second, the authors concluded that the EDO could promote greater orthopedic and dental changes in the anterior region of the maxilla than a hyrax expander, based on 10-day activation of the EDO's anterior screw and 6-day activation of the hyrax expander and when both were activated 1 complete turn per day. A discussion for the difference of opening distance of screws and activation days between 2 expanders would be valuable. Finally, the time points applied in this article included preexpansion (T1), the end of active expansion phase (T2), and 6 months after the active expansion period (T3). The dimension of midpalatal suture opening was measured on radiographs taken at T2. The interincisal diastema was calculated according to the difference between the values of oral photographs obtained at T1 and T2. Maxillary arch width was measured by the changes in digital dental models between T1 and T3. We request the authors to explain the reasons why time points were not consistent. Maxillary expander with differential opening vs Hyrax expander: A randomized clinical trialAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 157Issue 1PreviewThe aim of this 2-arm parallel trial was to compare the dentoskeletal effects of the expander with differential opening (EDO) and the Hyrax expander in the mixed dentition. Full-Text PDF Authors' responseAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 157Issue 6PreviewWe thank the authors for pointing out important questions and for the opportunity to discuss our study. Full-Text PDF