Introducción: Las anomalías dentomaxilares corresponden a un grupo de alteraciones que dificultan el desarrollo armónico de los maxilares, donde encontramos las anomalías transversales. La expansión rápida del maxilar (ERM) se utiliza como tratamiento de anomalías transversales, su objetivo es aumentar la distancia transversal por la separación de ambas hemiarcadas a nivel de la sutura palatina, utilizando un aparato expansor fijo y rígido. Los disyuntores más utilizados son los expansores Hass,

Objective:To determine user satisfaction with fixed orthodontic appliances during the first three checkups after installation. Materials and methods: A cross-sectional observational study was conducted with patients who started fixed orthodontic treatment in health centers in Paillaco and Valdivia. For this, a survey instrument validated in Spanish by Gacitúa et al. (2016) was used. To establish differences, the Friedman test was performed with a p<0.05 significance level. Results: Thirty-four patients participated (14.1 (SD ± 3.5) years old). The total satisfaction score was 37.94 (SD ± 7.13) points for the first month, 40.56 (SD ± 6.35) points for the second and 41.09 (SD ± 6.92) points for the third. Conclusion: General satisfaction levels with orthodontic appliances increase as the orthodontic treatment extends over time.