## 1 Introduction  
In recent years, the FDI World Dental Federation emphasized that oral health \"reflects the physiological, social and psychological attributes that are essential to the quality of life (QoL)\", and \"is influenced by the person's changing experiences, perceptions, expectations, and ability to adapt to circumstances\" [1]. In this context, orthodontic treatment planning should be based more and more on the concept of \"patient-centered care\", taking into account not only objective orthodontic results associated with an ideal occlusion, but also the patient's preferences, values, and needs [2]. Patient-reported outcome measures (PROMs) and patient-reported experience measures (PREMs) are increasingly recognized as providing valuable and essential information for achieving health system goals. Those instruments are used to assess information directly reported by the patient, without the interpretation of a clinician, that pertains to the patient's health, QoL, or functional status associated with health care or treatment [3, 4], among which satisfaction is one of the most important factors. Factors that influence patient and parental satisfaction have been extensively studied in the orthodontic literature [5; 6; 7; 8; 9; 10; 11; 12]. The systematic review authored by [PERSON] identified the most important factors that contribute to patient satisfaction: the doctor-patient relationship, the final appearance of the teeth, the doctor-staff relationship linked to quality of care and communication, and the patient's personality. In particular, clear and regular explanations enhanced the understanding of the treatment progress, thus increasing satisfaction and motivation. Furthermore, other factors likely to be associated with treatment satisfaction were treatment stability, sex (females were generally more dissatisfied with the appearance of their dentition than males), patient compliance, appliances, and treatment timing. Age was not associated with treatment outcome satisfaction [12]. Dental and skeletal malocclusions are frequent findings among growing individuals [13; 14; 15]. During growth, the goal of interceptive orthodontic treatments is to correct existing or developing skeletal, dentoalveolar, and/or muscular imbalances mostly in mixed dentition. The possible treatment approaches range from the interception of crowding problems to skeletal and facial modifications on the transversal [16], sagittal [17; 18; 19], and vertical planes. In the last decades, the use of elastodontic appliances (EAs) and clear aligners (CAs) has become widespread among orthodontists, with the aim of correcting different types of malocclusions at different ages [20; 21; 22]. These removable appliances are reported to be easy-to-use, comfortable, safe, and simple in construction and function [21; 23]. Furthermore, the use of removable appliances seems to have positive effects on oral hygiene and white spot development [24; 25]. These features make them suitable for early orthodontic treatment during the mixed dentition period. EAs are preformed, removable appliances made from silicone elastomer [26]. Their mechanism of action is a combination of neuromuscular, orthopedic, and dental effects [27]. These orthodontic devices have been suggested to treat many malocclusions, including crowding, excessive overjet, and distal bites. Furthermore, EAs normally require only minimal adjustments, allowing for less chair-side time and longer intervals between check-ups. Furthermore, retention can be carried out with the same appliance as the treatment [20]. Despite the widespread use of these devices, according to the authors' knowledge, satisfaction levels following treatment with EAs were not previously assessed in the literature. CA treatment was originally confined to adults. An aligner approach aimed at teenage patients was introduced in 2008, corresponding with the increased demand by younger patients for appliances that are both more esthetic and more comfortable than conventional fixed appliances [28].