Twin-block appliance had been advocated as a potential treatment option in paediatric obstructive sleep apnoea (OSA) due to their favourable effect in enhancing upper airway parameters and improving OSA symptoms. The aim of this study was to evaluate the effect of twin-block appliance therapy on upper airway parameters/dimensions and the apnoea-hypopnea indexes (AHIs) in OSA children with class II mandibular retrognathic skeletal malocclusion using cone-beam computed tomography. This prospective longitudinal study comprised 34 polysomnography-proven OSA growing children with class II mandibular retrognathic skeletal malocclusion between the ages of 8 and 12 years who had completed myofunctional twin-block therapy and matched corresponding controls. The upper airway was segmented into the nasopharynx, oropharynx, and hypopharynx, and the effect of twin-bock treatment on upper airway parameters/dimensions was assessed pre- and posttreatment using CBCT analysis, while a second standard overnight PSG was performed to determine changes in the AHI. At the nasopharynx level, minimal (nonsignificant) increases in all variables were observed within the twin-block group and between the groups (P > 0.05). At the level of the oropharynx, all variables increased significantly in the treatment group and between groups (P < 0.001), but these increases were nonsignificant in the control group. At the level of the hypopharynx, only the minimum cross-sectional area (MCA) increased significantly in the treatment group (P = 0.003). The change in MCA was also significant between the groups (P = 0.041). In addition, the upper airway length increased significantly in the twin-block group (P = 0.0154), and the AHI decreased by 74.8% (P < 0.001).

Conclusion: Correction of class II mandibular retrognathic skeletal malocclusion with twin-block appliance resulted in a significant increase in upper airway volume, MCA, anteroposterior and lateral distances of the MCA at the level of the oropharynx, MCA at the level of the hypopharynx and upper airway length, and a significant decrease in AHI, but it had no effect on nasopharynx parameters.

双阻滞矫治器因其在增强上呼吸道参数和改善 OSA 症状方面的良好作用而被提倡作为小儿阻塞性睡眠呼吸暂停 (OSA) 的潜在治疗选择。本研究的目的是使用锥形束计算机断层扫描评估双阻滞矫治器治疗对 II 类下颌后颌骨错牙合畸形 OSA 儿童上气道参数/尺寸和呼吸暂停低通气指数 (AHI) 的影响。这项前瞻性纵向研究包括 34 名经多导睡眠图证实患有 OSA 的生长发育儿童，年龄在 8 至 12 岁之间，患有 II 级下颌后颌骨错牙合，他们已完成肌功能双阻滞治疗并匹配相应的对照。将上气道分为鼻咽部、口咽部和下咽部，并使用 CBCT 分析在治疗前和治疗后评估双块治疗对上气道参数/尺寸的影响，同时进行第二个标准隔夜 PSG 以确定AHI。在鼻咽水平，双阻滞组内和组间所有变量均观察到最小（不显着）增加（ P > 0.05）。在口咽水平，所有变量在治疗组和组间均显着增加（ P <0.001），但这些增加在对照组中不显着。在下咽水平，治疗组仅最小横截面积（MCA）显着增加（ P = 0.003）。各组之间 MCA 的变化也很显着（ P = 0.041）。此外，双阻滞组的上气道长度显着增加（ P = 0.0154），AHI 降低了 74。8%（ P <0.001）。

结论：双阻滞矫治器矫正II类下颌后骨性错牙合畸形，可显着增加上气道容积、MCA、口咽水平MCA的前后向和侧向距离、下咽水平和上咽水平的MCA。气道长度和 AHI 显着降低，但对鼻咽参数没有影响。