MEDIUM-TERM EFFECTS OF RAPID MAXILLARY EXPANSION ON NASAL CAVITY AND PHARYNGEAL AIRWAY VOLUMES CONSIDERING AGE AS A FACTOR: A RETROSPECTIVE STUDY

Objectives. The medium-term effects of rapid maxillary expansion (RME) on nasal\r\ncavity (NC) and upper airway (UA) dimensions based on chronological age are still\r\nunclear. This retrospective study evaluated the medium-term changes occurring in the\r\nNC and pharyngeal airways (PA) after RME in two distinct age-based cohorts. Methods.\r\nThis retrospective study included 48 subjects who underwent RME grouped in two\r\ncohorts: a 6-9-year-old group (EEG group: early expansion group - 25 subjects) and an\r\n11-14-year-old group (LEG group: late expansion group - 23 subjects). NC and PA\r\nvolumes were analyzed from CBCT imaging segmentation before RME (T0) and twelve\r\nmonths after RME (T1). The amount of maxillary expansion (PW) and minimal crosssectional area (CSmin) were also considered. Results. All PAs’ volumetric sub-regions,\r\nCSmin and PW showed a significant volumetric increment (p<0.05). Inter-group\r\ncomparisons showed significant differences (p<0.05) for nasopharynx and CSmin\r\nparameters (p<0.05), while no significant changes were recorded for the other UA’s subregions and PW (p>0.05). According to a deviation analysis, part of the UA increase\r\n(more marked for the nasopharynx area) may have occurred due to reduced\r\nadenotonsillar tissues, which were larger in the EEG group. Conclusions. Twelve\r\nmonths after treatment, clinicians should not expect changes in the UAs dimensions to\r\nbe solely related to treatment effects of RME; instead, normal craniofacial growth\r\nchanges and spontaneous regression of the adenotonsillar tissue could represent the most\r\nsignificant factors influencing UAs changes. Clinical Significance. From the clinical\r\nperspective, the results of the present study encourage caution when considering the\r\ntherapeutic effects of RME on airways dimensions.