Effects of extraction versus non-extraction treatment on oropharyngeal airway volume

Abstract

Objective: To compare the effects of extraction vs nonextraction orthodontic treatments on oropharyngeal airway volume. Materials and Methods: An existing patient database was screened for pretreatment (T0) and posttreatment (T1) cone beam computed tomography (CBCT) scans and complete medical histories. Twenty patients treated with removal of four premolars (ExtG) and 20 controls (NExtG), were matched for age, gender, ethnicity, height, weight, body mass index, and oropharyngeal (OP) volumes, among other variables. Constructed lateral cephalograms (three skeletal and four dental variables) and OP volumes were measured at T0 and T1 using Dolphin Imaging 11.0. Independent sample t-tests were used to compare the groups at T0 and the outcome variables at T1. Paired sample t-tests were used to compare the mean changes from T0 to T1. Statistical significance was set at P # .05. Results: Changes from T0 to T1 were found to be significant in both groups for CoA, CoGn, U1-FH, and IMPA. In the ExtG alone, U1-Na Perp and L1-Na Perp were also significantly different from T0 to T1. Despite the observed differences, no significant differences were found at the end of treatment between the mean OP volumes for either group (12,675.6 6 4483.6 for ExtG; 12,002.7 6 2857.0 for NExtG, P . .05). Similarly, the mean changes in OP volume (1082.6 mm 3 and 1701.1 mm 3 for ExtG and NExtG, respectively) and increase in mean minimal constricted axial areas (17.4 mm 2 and 1.9 mm 2 for ExtG and NExtG, respectively, P . .05) from T0 to T1 were not significant for the two groups. Conclusion: Extraction of four premolars with retraction of incisors does not affect OP airway volume.

Effect of retraction of anterior teeth on pharyngeal airway and hyoid bone position in Class I bimaxillary dentoalveolar protrusion

“…The authors supported their negative finding to mandibular growth. In their study, 10 anchorage reinforcement system was not specified, while in our study, TPA/Nance button with headgears was applied for Group A type of anchorage similar to the study by Wang et al 9 who had used mini-implants/headgear, which may be the reason for the different results. In the study by Wang et al, they have not specified the distribution of patients wearing headgear/miniimplants.…”

“…adaptation leading to the decrease in the size of the upper airway. 10 According to a recent study by Valiathan et al, 10 pharyngeal airway did not change significantly after retraction of anterior teeth with extraction of four premolars in adolescents. The authors supported their negative finding to mandibular growth.…”

“…A recent study 9 showed that the orthodontic treatment with extraction of four premolars did influence oropharyngeal airway space in adults. Another study 10 showed that the same orthodontic treatment did not influence oropharyngeal airway in adolescents. This finding has been supported due to pharyngeal growth in adolescents, but specific changes at all levels of pharyngeal airway and hyoid bone were not considered.…”

“…6 The correlation between craniofacial growth pattern and pharyngeal airway was found to be doubtful. 7,8 Limited evidence-based research 9,10 is available on the correlation of the retraction of anterior teeth in bimaxillary protrusion patients undergoing extraction of four premolars and the pharyngeal airway. A recent study 9 showed that the orthodontic treatment with extraction of four premolars did influence oropharyngeal airway space in adults.…”

“…These changes are likely to influence tongue position and pharyngeal airway. 10 Literature about this aspect is still not sufficient, and therefore it is necessary to investigate the effect of retraction of anterior teeth on pharyngeal airway.…”