A 6-months Evaluation of Patients' Compliance and Oral Hygiene During Rapid Maxillary Expander (RME) Treatment Using "Ortodontika" Smartphone Application

The aim of this study is to evaluate the clinical use of the smartphone application "Ortodontika" for the compliance of orthodontic patients with Rapid Maxillary Expander (RME). Patients and parents consenting to participate in the study will sign the informed consent for their child. At the baseline (T0), a periodontal examination will be carried out by means of a probe (UNC probe 15; Hu-Friedy, Chicago, IL, USA) assessing Bleeding Index, Plaque Index and Modified Gingival Index on upper first incisors, first premolars/first primary molars and first molars. A professional oral hygiene will be performed using a piezoelectric instrument (Multipiezo, Mectron S.p.a, Carasco, Italy) and a manual scaler (LM23, LM-Dental, Pargas, Finland). A RME will be cemented with a glass ionomer cement (3M Multi-Cure, 3M Unitek, Monrovia, CA, USA) on the maxillary first molars and will be activated by parents on clinicians' instructions. Patients will receive an oral hygiene kit containing toothpaste (GUM Junior 7+, Sunstar Deutschland GmbH, Schonau, Germany), soft-bristled toothbrush (GUM Technique PRO toothbrush), interdental brush 0.6 and 0.8 mm of diameter (GUM TRAV-LER) and a single tufted brush (GUM End-Tuft). Orthodontic wax will be given for emergencies related to RME (GUM ORTHO wax) and 1% chlorhexidine gel (Curasept Periodontal gel, Curasept S.p.A, Saronno, VA, Italy) will be given for gingival inflammation. At this point, patients will be divided into two groups: * Control group: verbal instructions on the correct activation of the RME and on its cleaning will be given to parents at each visit, together with verbal instructions on the correct daily practices for oral hygiene; * Trial group: use of "Ortodontika" smartphone application as adjunct to verbal instructions on the correct activation of the RME to be performed by one parent, through a daily notification until T1 (end of activations); parents will have to supervise daily oral hygiene of RME and the correct daily practices for oral hygiene. A notification will be sent every 2 weeks until the end of the study to remind patients to watch the videos on oral hygiene maneuverers. Patients will be visited at the end of the activations (T1), after 1.5 months (T2), after 3 (T3) and 6 months (T6). At the recall, the periodontal indices will be evaluated and a questionnaire will be given to patients. At each recall, extra products will be given for home oral hygiene. During the study, the number of emergencies will be recorded: RME decementation, patients perceiving pain related to plaque accumulation, mucosal ulcerations due to vestibular tubes, parents that do not understand how to perform RME activations, patients asking the clinician to perform RME activations chairside. A questionnaire will be given to patients and parents belonging to both groups to evaluate awareness of orthodontic therapy aims and phases, knowledge of oral hygiene maneuverers. A questionnaire about Ortodontika application usefulness will be given only to patients and parents belonging to Trial group.