Crescimento facial vertical de crianças respiradoras orais: estudo comparativo e evolutivo da avaliação cefalométrica, do comportamento mandibular rotacional e da remodelação angular

Abstract

Introduction: The association between mouth breathing and dentofacial growth has been described in literature at least since the mid-nineteenth century, but early in the beginning of the XXI century there is still a number of questions about this relationship. Despite the fact that the long facial type has been recognized as a stereotype of mouth-breathers, the investigations on the influence of different obstructive etiologic factors on the facial morphology are scarce. Little is also known about the mandibular rotation and angular remodeling of MB children before and after adeno-/tonsillectomy. Therefore, the aim of this study was to evaluate the cephalometric pattern, the mandibular rotation and angular remodeling in MB children with severe obstruction of the upper airway due to adenoid and/or tonsils hypertrophy. The specific aims were: 1) to compare the cephalometric pattern of MB children with different obstructive etiologies between each other and 2) with NB children; 3) to compare mandibular rotation and angular remodeling of MB with NB children for one year of observation, 4) to assess whether it is possible to predict the mandibular rotation and angular remodeling based on the vertical facial type of MB and NB children; 5) to evaluate whether MB children undergone surgical treatment for normalization of breathing pattern present mandibular rotation and angular remodeling similar to NB children, and especially in an unprecedented manner, to compare their mandibular rotational behavior with the mandibular rotation of untreated MB children for one year of observation. Patients and Methods: We selected MB children with adenoid hypertrophy 80% and/or tonsils hypertrophy of grades 3 or 4 subdivided in two ways: 1) MB children with diferentt causes of obstruction (group 1 adenoid hypertrophy, group 2 tonsils hypertrophy and group 3 adenoid and tonsils hypertrophy) and 2) treated MB children (adeno-/tonsillectomised) and untreated MB children. NB children were also selected. The mean of the angular cephalometric measurements and proportions were compared transversely and the measurements of the mandibular rotation and angular remodeling were compared longitudinally. Results: All measurements of interest showed a statistically significant difference when comparing MB and NB children (control group - CG) except for SNB. MB children with different causes of obstruction, separately, showed statistically significant differences when compared with the NB children (SNB was higher in group 1; ANB was higher in groups 1, 2 and 3; PFH/TAFH was lower in groups 1, 2 and 3; SNGnGO, NSGn, LAFH/TAFH were higher in groups 1 and 3 vs. CG). Comparing groups 1, 2 and 3 with each other, the differences were: SNB and PFH/TAFH were higher in group 2 than in group 1 and NSGn was lower in group 2 than in group 1. As for the longitudinal evaluation, we found no statistically significant difference between the MB and NB children in the real rotation or apparent rotation, but there was significant difference in angular remodeling over one year. The comparison between treated MB children with untreated MB children showed no differences in apparent rotation, real rotation and angular remodeling despite the latter two measurements have higher values in treated MB children than in untreated 17 Abstract MB children. Conclusions: There is a clear difference between the angular cephalometric measurements and proportions of MB and NB children regardless of the obstructive etiology; SNB and NSGn angles and the proportion PFH/TAFH are different depending on the site of airway obstruction; in MB children, due to tonsils hypertrophy, the position of the mandible was more anterior and superior than in MB children associated with adenoid hypertrophy. MB children did not show the same pattern of angular remodeling compared with NB children but it cannot be said that the MB children have different patterns of mandibular real rotation nor apparent rotation when compared with NB children and, surprisingly, MB and NB children have the same pattern of counterclockwise mandibular rotation. It is not possible to predict the mandibular rotation and angular remodeling of MB and NB children based on the vertical facial type. The treated MB children did not show a different pattern of mandibular rotation and angular remodeling from NB children and, especially, from untreated MB children.