Influence of Respiration in Maxillary Pattern and Facial Growth Direction

OBJECTIVES: The purpose of this transversal study was to evaluate the possible influence of respiratory pattern in maxillary development and facial growth direction. METHODS: The sample comprised lateral cephalometric radiographs of 100 white Brazilian youths, with 8 to 13 years of age, that were never submitted to orthodontic treatment, divided into two groups: 48 nasal breathers and 52 oral ones. The methodology involved the evaluation of diverse linear and angular cephalometric variables, commonly employed in McNamara, Ricketts and USP analysis. The statistical evaluation used students “t” test and test of correlation (r), with a confidence level of 95%. RESULTS: Oral breathers revealed significantly greater mean values for the following variables: ANB, ANS-PNS (length of hard palate), NS.Ocl (occlusal plane inclination in relation to anterior cranial base), GoMe.ocl (occlusal plane inclination in relation to mandibular plane), NS.GoMe (mandibular plane inclination in relation to anterior cranial base), FMA and ALFH (anterior lower face height). However, the variable ANS-PNS showed a smaller value for oral breathes in comparison with nasal ones. CONCLUSIONS: Oral breathers presented a trend towards vertical facial growth pattern, with increased lower anterior face height. Furthermore, they also exhibited a trend towards counter clockwise rotation of palatal plane, a greater anteroposterior length of hard palate, as well as a deficient relationship between maxillary and mandibular skeletal bases, which was demonstrated by an increased ANB angle.