A 22-year follow-up of the nonsurgical expansion of maxillary and mandibular arches in a young adult: Are the outcomes stable, relapsed, or unstable with aging? Jos e Valladares-Neto, a Karine Evangelista, b Hianne Miranda de Torres, b Matheus Melo Pithon, c and Maria Alves Garcia Santos Silva d Goi^ ania, Goi as, and Jequi e, Bahia, Brazil Adult maxillary and mandible arch expansion without a surgical approach can be uncertain when long-term sta- bility is considered. This case report describes the treatment of a 19-year-old woman with an Angle Class I malocclusion with constricted maxillary and mandibular arches. The patient's main complaint was mandibular anterior crowding. The treatment plan included expansion of the mandibular arch concurrent with semirapid maxillary expansion. An edgewise appliance was used to adjust the final occlusion. Smile esthetics and dental alignment were improved without straightening the profile. This outcome was followed up with serial dental casts for 22 years after treatment. At the end of that period, the occlusion and tooth alignment were clinically satisfac- tory, further supported by mandibular fixed retention. However, the transverse widths were continuously and gradually reduced over time, superposing orthodontic transverse relapse and natural arch constriction caused by aging. (Am J Orthod Dentofacial Orthop 2016;150:521-32) S uccessful orthodontic treatment is also referred to as long-term stability. However, orthodontic relapse and physiologic changes with age can pro- duce dental arch instability. Longitudinal studies have shown that tooth position can be physiologically changed with aging in untreated subjects because of progressive arch constriction. 1-3 These 2 phenomena are probably superposed in treated subjects during the postretention period. 4 As regards the transverse dimension, constricted arch problems have been solved through expansion, and increments in arch dimensions have been clearly demonstrated. 5,6 However, most studies on maxillary and mandibular arch expansion have dealt with subjects in the mixed and early permanent dentitions, and only a few authors have studied long-term results. 5,7-9 In young adults, the prognoses for rapid maxillary expansion and semirapid maxillary expansion (SRME) in terms of palatal suture opening are uncertain due to the rigidity of the skeletal components with advancing maturity. 10 This prevents or limits the extent of suture opening and results in a greater dentoalveolar than a skeletal response, with an unpredictable long-term outcome. 11 On the other hand, the response of mandib- ular arch expansion is only dentoalveolar, and it has been recommended in the case of a constricted arch. 6,8 Nevertheless, the changes in mandibular arch form have controversial results and could adversely affect long- term stability and treatment outcomes. 12 In contrast, other studies have shown that mandibular arch forms can be successfully expanded in the early stages. 5,8,9 Because dental and skeletal long-term stability is a key objective in orthodontics, and the tendency toward relapse is a real problem superposed by changes caused a Adjunct professor, Division of Orthodontics, School of Dentistry, Federal Univer- sity of Goi as, Goi^ ania, Goi as, Brazil. b Postgraduate student (PhD), School of Dentistry, Federal University of Goi as, Goi^ ania, Goi as, Brazil. c Professor, Department of Orthodontics, School of Dentistry, Southwest Bahia State University, Jequi e, Bahia, Brazil. d Professor, Department of Stomatologic Sciences, School of Dentistry, Federal University of Goi as, Goi^ ania, Goi as, Brazil. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Address correspondence to: Jos e Valladares-Neto, Division of Orthodontics, Federal University of Goi as, Avenida Universit aria esquina com 1 a Avenida, s/n, Setor Universit ario, CEP: 74.605-220, Goi^ ania, Goi as, Brazil; e-mail, jvalladares@uol.com.br. Submitted, May 2015; revised and accepted, October 2015. 0889-5406/$36.00 Ó 2016 by the American Association of Orthodontists. All rights reserved. http://dx.doi.org/10.1016/j.ajodo.2015.10.030 521 CASE REPORT