Impact of tonsillectomy on the efficacy of Alt-RAMEC/PFM treatment protocols in children with class III malocclusion and tonsillar hypertrophy: protocol for a cluster randomised controlled trial.

INTRODUCTION: Orthodontic treatment using face mask protraction combined with an alternate rapid maxillary expansion and constriction/protraction face mask (Alt-RAMEC/PFM) protocol is effective in the early treatment of patients with class III malocclusion, but the stability of treatment outcomes represents a major concern. Previous studies have suggested that tonsillar hypertrophy can be a risk factor for class III malocclusion and tonsillectomy may prompt the normalisation of dentofacial growth. However, these studies had a low-to-moderate level of evidence. This study was designed to identify the impact of tonsillectomy before orthodontic treatment on the efficacy and stability of Alt-RAMEC/PFM protocols and the sleep quality and oral health in children with anterior crossbite and tonsillar hypertrophy. METHODS AND ANALYSIS: This is a two-arm, parallel-group, superiority cluster randomised controlled trial, with four clinics randomly assigned to the surgery-first arm and the orthodontic-first arm in a 1:1 ratio. The Alt-RAMEC protocol involves alternate activation and deactivation of the expander's jet screw over 6 weeks to stimulate maxillary suture distraction. Patients will be instructed to wear the PFM for a minimum of 14 hours per day. The primary outcomes are changes in Wits appraisal and the degree of maxillary advancement from baseline to the end of orthodontic treatment. Lateral cephalometric radiographs, polysomnography, Obstructive Sleep Apnoea-18 questionnaire and Oral Health Impact Profile-14 questionnaire will be traced, collected and measured. We will recruit 96 patients intofor the study. To assess differences, repeated multilevel linear mixed modelling analyses will be used. ETHICS AND DISSEMINATION: This study has been granted ethical approval by the Ethics Committee of the School & Hospital of Stomatology, Wuhan University (approval No. 2023-D10). Written informed consent will be obtained from the participants and their guardians. The results of the trial will be disseminated through academic conferences and journal publications. TRIAL REGISTRATION NUMBER: ChiCTR2300078833.

Functional therapy and adenotonsillectomy clinical trial for class II malocclusion (FACT-II): protocol for a randomised controlled trial.

INTRODUCTION: Class II malocclusion with mandibular retrognathia is a common complication of paediatric obstructive sleep apnoea (OSA), often accompanied by transverse maxillary deficiency. In early orthodontic treatment, a twin block (TB) is a regular functional appliance for correcting this malocclusion. For paediatric OSA, the most common risk factor is adenotonsillar hypertrophy (AHT). Untreated AHT may lead to the persistence and worsening of obstructive sleep-disordered breathing traits, including habitual mouth breathing. Additionally, the clockwise mandibular rotation associated with AHT-induced pharyngeal crowding can undermine the effectiveness and stability of TB treatment. Adenotonsillectomy (T&A) is currently the first-line treatment for paediatric OSA. This proposed trial will investigate the impact of T&A surgery timing on the efficacy and stability of TB functional treatment in children with class II mandibular retrognathia and ATH. METHODS AND ANALYSIS: This will be a single-centre, parallel-group, superiority randomised controlled trial with participants randomised to intervention (T&A followed by TB treatment) or control arms (TB treatment followed by T&A) in a 1:1 ratio. A total of 40 patients aged 8-14 years, diagnosed with class II mandibular retrognathia and co-existing ATH-induced OSA, and indicated for both T&A surgery and TB treatment, will be recruited at the School and Hospital of Stomatology, Wuhan University. The primary outcomes will be the changes in the apnoea-hypopnoea index and the point A-nasion-point B angle from baseline to postorthodontic treatment between the two groups. Secondary outcomes will include other dental, skeletal, upper airway and soft tissue changes, as well as subjective sleep-related and oral-related quality of life. Outcome changes within each group and between groups will be analysed. ETHICS AND DISSEMINATION: This study is approved by the Ethics Committee of the School and Hospital of Stomatology, Wuhan University (no. 2022-D07). The research findings will be faithfully disseminated through scientific conferences or published articles. TRIAL REGISTRATION NUMBER: ChiCTR2200061703 (https://www.chictr.org.cn).