Three-dimensional evaluation of pharyngeal airway and maxillary arch in mouth and nasal breathing children with skeletal Class I and II.

OBJECTIVE: This study aimed to investigate whether the subjects with mouth breathing (MB) or nasal breathing (NB) with different sagittal skeletal patterns showed different maxillary arch and pharyngeal airway characteristics. METHODS: Cone-beam computed tomography scans from 70 children aged 10 to 12 years with sagittal skeletal Classes I and II were used to measure the pharyngeal airway, maxillary width, palatal area, and height. The independent t-test and the Mann-Whitney U test were used for the intragroup analysis of pharyngeal airway and maxillary arch parameters. RESULTS: In the Skeletal Class I group, nasopharyngeal airway volume (P < 0.01), oropharyngeal airway volume (OPV), and total pharyngeal airway volume (TPV) (all P < 0.001) were significantly greater in subjects with NB than in those with MB. Furthermore, intermolar width, maxillary width at the molars, intercanine width, maxillary width at the canines, and palatal area were significantly larger in subjects with NB than in those with MB (all P < 0.001). In the Skeletal Class II group, OPV, TPV (both P < 0.05) were significantly greater in subjects with NB than in those with MB. No significant differences in pharyngeal airway parameters in the MB group between subjects with Skeletal Class I and those with Skeletal Class II. CONCLUSION: Regardless of sagittal Skeletal Class I or II, the pharyngeal airway and maxillary arch in children with MB differ from those with NB. However, the pharyngeal airway was not significantly different between Skeletal Class I and II in children with MB.

A non-randomized concurrent controlled trial of myofunctional treatment in the mixed dentition children with functional mouth breathing assessed by cephalometric radiographs and study models.

OBJECTIVES: This study aimed to examine the clinical effects of myofunctional treatment on children with functional mouth breathing by cephalometric radiographs and study models. METHODS: A total of 224 children (6-10 years old; 114 males and 110 females; SNA°: 82.24 ± 1.67°; ANB°: 2.79 ± 0.80°, 28° < SN-GoGn° < 37°) formed three groups: MB-M group (mouth breathers with myofunctional treatment,n = 75); MB-N group (mouth breathers with no treatment,n = 70); NB group (nasal breathers with no treatment, n = 79). A blind evaluation of cephalometric radiographs and study models was conducted at T1(pre-study) and T2 (post-study), respectively. RESULTS: Two hundred four children (MB-M:66, MB-N:68, NB:70) completed the present study. At T1, MB-M and MB-N groups, compared to their NB counterpart, had greater anterior lower facial height(P < 0.01) and overjet(P < 0.001) but shorter overbite and maxillary canines width (P < 0.001). At T2, the MB-N group exhibited a higher ANB angle, anterior lower facial height, and overjet, but shorter overbite and maxillary canines width (P < 0.001). From T1 to T2, the anterior lower facial height increased, overbite and the maxillary canines width further decreased in the MB-N group (P < 0.001). However, in the MB-M group, the incisors were retracted, overbite increased (P < 0.001), anterior lower facial height increased insignificantly (P > 0.05), and maxillary canines width increased slightly (P < 0.05). In the NB and MB-M groups, the mandible showed a normal tendency to grow forward, whereas, in the MB-N group, the mandible showed a tendency to grow downward (P < 0.001). CONCLUSIONS: Mouth breathers demonstrated increased anterior facial height and overjet but reduced overbite and maxillary arch width, which improved significantly following myofunctional treatment. TRIAL REGISTRATION: TCTR: TCTR20220401001 . Registered 1stApril 2022-Retrospectively registered.