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

Objectives: 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.
Methods: 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.
Results: 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.
Conclusions: 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.