Mouth breathing children and cephalometric pattern: does the stage of dental development matter?

To test the hypothesis that there is no difference in the cephalometric pattern between mouth breathing children with primary dentition and mixed dentition.

Cephalometric measurements of 126 mouth breathing children (MB) were compared to 126 nasal breathing controls (NB). Both groups were divided into deciduous dentition (mean age 4 years, 8 months) and mixed dentition (mean age 7 years, 9 months) groups.

A statistically significant difference was observed in the dentofacial patterns of MB children compared to NB children. The total length of the mandible was smaller in MB compared to NB children. However, this difference was found only in subjects with mixed dentition. The length of the mandibular corpus is similar in MB and NB children, although older MB children with mixed dentition had significantly smaller measurements. The lower anterior facial height was higher in MB compared to NB children, but this difference was evident only in younger children with primary dentition. Mandibular plane angle, Y-axis angle and lower anterior facial height to total anterior facial height ratio were greater, and posterior facial height to total anterior facial height ratio was smaller in MB than NB children, indicating that mouth breathers had a more vertical facial growth pattern. However, no differences were found in the vertical growth pattern associated with the stage of dental development. The ANB angle was not associated with the maturational status of occlusion. Linear measurements and the gonial angle were significantly different between children with primary and mixed dentition, but such differences were associated with normal vertical growth.

The present investigation rejected the null hypothesis and showed significant cephalometric differences between primary and mixed dentition MB children. Mouth breathing children in the mixed dentition have a smaller mandible (in terms of total length and corpus length) than nasal breathers. In children with primary dentition, the lower anterior facial height is higher in MB than in NB children. There was no significant association between the stage of dental development of mouth breathing children (either in the primary or mixed dentition) and the other cephalometric patterns.