Effects of Four First Premolar Extraction on the Upper Airway Dimension in a NonGrowing Class I Skeletal Patients: A Systematic Review

Abstract

Objective: Orthodontic treatment aims not only to treat one's malocclusion and facial aesthetics but also to maintain or improve the patient's airway patency. This review aims to evaluate post-treatment changes in the position of hyoid bone and oropharyngeal airway size and dimensions associated with fixed orthodontic treatment with four first bicuspid extractions in non-growing Class I skeletal bimaxillary protrusion individuals. Methods: Electronic databases including Embase, Web of Science, PubMed, and Scopus were used to research published articles. Included studies assessed the post-treatment effects of four first bicuspid extractions with maximum anchorage on pharyngeal airway dimensions in non-growing patients. Relevant data were obtained, summarised, and analysed from the included studies. © 2020 Terese Winslow LLC, U.S. Govt. has certain rights. OSA is one of the sleep-breathing disturbances caused by collapsing of the upper airway during sleep, characterised by cessation of airflow with persistent respiratory effort, oxygen de-saturations, sleep arousals and sleep fragmentation [4]. Although OSA is a multifactorial disorder associated with obesity, age, facial morphology, airway collapsibility, and neuromuscular feedback, the size of the oropharyngeal airway is highly associated with OSA severity [5-12].Results: Six articles were selected in this systematic review after meeting the requirements of the inclusion criteria. Conclusions: Four bicuspid extractions followed by maximum anchorage involves predominant retraction of the anterior segment of the arches in non-growing skeletal Class I bimaxillary protrusion cases. Extraction of four first premolars led to retraction of the anterior segment and the retroclination of anterior teeth, which narrowed the pharyngeal airway dimensions. After such treatment, the hyoid bone position changes remain inconclusive, which warrants further studies.