Comparison of craniofacial morphology, head posture and hyoid bone position with different breathing patterns

The aim of this study was to evaluate differences in craniofacial morphology, head posture and hyoid bone position between mouth breathing (MB) and nasal breathing (NB) patients.

Mouth breathing patients comprised 34 skeletal Class I subjects with a mean age of 12.8 ± 1.5 years (range: 12.0-15.2 years). Thirty-two subjects with skeletal Class I relationship were included in the NB group (mean 13.5 ± 1.3 years; range: 12.2-14.8 years). Twenty-seven measurements (15 angular and 12 linear) were used for the craniofacial analysis. Additionally, 12 measurements were evaluated for head posture (eight measurements) and hyoid bone position (four measurements). Student's t-test was used for the statistical analysis. Probability values <0.05 were accepted as significant.

Statistical comparisons showed that sagittal measurements including SNA (p < 0.01), ANB (p < 0.01), A to N perp (p < 0.05), convexity (p < 0.05), IMPA (p < 0.05) and overbite (p < 0.05) measurements were found to be lower in MB patients compared to NB. Vertical measurements including SN-MP (p < 0.01) and PP-GoGn (p < 0.01), S-N (p <0.05) and anterior facial height (p < 0.05) were significantly higher in MB patients, while the odontoid proses and palatal plane angle (OPT-PP) was greater and true vertical line and palatal plane angle (Vert-PP) was smaller in MB patients compared to NB group (p < 0.05 for both). No statistically significant differences were found regarding the hyoid bone position between both groups.

The maxilla was more retrognathic in MB patients. Additionally, the palatal plane had a posterior rotation in MB patients. However, no significant differences were found in the hyoid bone position between MB and NB patients.