Effects of bicuspid extractions and incisor retraction on upper airway of Asian adults and late adolescents: A systematic review

Abstract

ObjectivesThis systematic review aimed to assess the effects of bicuspid extractions and incisor retraction on airway dimension, hyoid position and breathing of adults and late adolescents.MethodsThe review was conducted according to PRISMA guidelines. Eight databases including PubMed, EMBASE, Web of Science and Scopus were searched to August 2018. Minimum age of participants was 16 years. The intervention was dual‐arch bicuspid extractions with incisor retraction. Outcomes were airway dimension, hyoid position and breathing assessment.ResultsAll nine publications meeting inclusion criteria were from Asia. They were divided into three Asian subregions. All East Asian lateral cephalometric studies reported anteroposterior airway narrowing at the oropharynx and sometimes the hypopharynx. However, the narrowing was small, comparable to measurement errors, and highly variable. Two out of three East Asian computed tomography (CT) studies described reductions in airway dimensions. The single functional breathing study showed increased simulated flow resistance after incisor retraction in East Asians. South Asian studies had mixed findings, with some reporting significant airway narrowing. The single study from West Asia found no significant airway or hyoid changes.ConclusionsAirway response to bicuspid extractions and incisor retraction varied substantially when assessed with cephalometry. CT measurements present larger effect sizes and smaller variations, providing stronger evidence of airway narrowing. Orthodontic extractions for incisor retraction may be more frequently indicated in Asia, and East Asians seem particularly susceptible to airway narrowing and postero‐inferior hyoid movement with incisor retraction. Better designed CT studies are needed for confirmation due to small effect size and large variability.

Extraction vs. Nonextraction on Soft-Tissue Profile Change in Patients with Malocclusion: A Systematic Review and Meta-Analysis

“…Also, extraction leaves less space for the tongue as the arches become smaller, forcing the tongue to take a backward position, leading to airway blockage and mouth breathing problems [ 35 ]. Extraction treatment has also been associated with a higher risk for sleep apnea with its many complications due to restricted space [ 36 ]; however, this has been contested [ 37 ]. More significantly, extraction has been variably linked to chronic pain and functional bite issues resulting from retraction [ 38 – 41 ].…”

Airway changes in patients with sleep apnea using AdvanSync2 Class II correctors – a case series

“…Post pubertal Class II skeletal cases can also be treated with bicuspid extractions. Studies suggest that patients treated with therapeutic orthodontic bicuspid extractions are more prone to airway obstruction due to retraction of incisors into the tongue space [29,30]. Hence, a tailored treatment plan, as per each patient's craniofacial morphology, aesthetics and functional efficiency should be planned.…”

Apnea Obstructiva del Sueño y el Rol del Ortodoncista. Revisión bibliográfica.

“…Es relevante analizar críticamente qué es lo que la evidencia disponible dice al respecto, y con ello, evitar la desinformación, sobre todo en el ámbito ortodóncico. Las revisiones sistemáticas disponibles al respecto plantean que la realización de extracciones puede reducir las dimensiones de la orofaringe, la que se daría junto a un descenso del hueso hioides, con gran variabilidad según la etnia (43) y dependiendo de la indicación de extracción, particularmente cuando se realizan para la retracción de incisivos, no así para tratar apiñamiento (44) . Sin embargo, los artículos reportados sólo se basan en la medición de dimensiones, sin evaluar la funcionalidad con un estudio de PSG de los sujetos.…”