Date: April 2024.
Source: BMJ Open. 14(4):e079571. doi: 10.1136/bmjopen-2023-079571. PMID: 38626960; PMCID: PMC11029268.
Background: 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.
Objective: This study is designed to investigate the impact of T&A performed prior to or after indicated O/DO treatment on (1) the effectiveness and stability of TB functional treatment and (2) the sleep quality, quality of life and oral health in children with class II mandibular retrognathia and ATH comorbidity.
Materials and Methods: 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.
Conclusions: In summary, this study will serve as evidence to guide clinicians in deciding whether to perform the T&A on patients prior to functional therapy based on a wide range of objectively and subjectively measured outcomes and provide a reference for multidisciplinary management of OSA with craniofacial alterations in growing children.

Article: Functional therapy and adenotonsillectomy clinical trial for class II malocclusion (FACT-II): protocol for a randomised controlled trial.
Authors: F Guo, C Lv, B Tang, L Lin, C Zhang, J Zheng, T Zhao, H He. School and Hospital of Stomatology, Wuhan University, Wuhan, China.