Evaluation of morphological relations between lower craniofacial skeletal structures and dimensions of upper respiratory tract in skeletal Classes I and III

Introduction. Review of the literature indicates the
relationship between upper airways patency and
lower jaw morphology. Aim of the study. To design
multidimensional models to describe morphological
relations of the linear and angular dimensions of
hard tissues of the lower facial skeleton and the
cervical spine (independent variables) with the
linear dimensions of the upper respiratory tract (dependent variables). The obtained models took
into consideration the age, gender and the skeletal
Class I and III of the evaluated individuals. Material
and method. The patients represented two skeletal
classes: I (n = 97; 42.4%) and III (n = 53; 23.1%).
Prior to orthodontic treatment, lateral cephalometric
radiography (LCR) was performed in all patients. The
obtained cephalometric measurements were evaluated
statistically. Results. The statistical analysis pointed
to significant differences between variables of the
URT and dimensions of the facial skeleton and the
cervical spine. It also revealed significant differences
between variables of the URT and dimensions of the
facial skeleton and the cervical spine. The independent
variable Co-Gn emerged as an important predictor
in regression of the nasopharynx. The anteroinferior
height of the face and mandibular inclination were
the factors relevant for oropharynx. Variables of
the cervical spine were significant predictors in
laryngopharyngeal models. Conclusions. The results
illustrating morphological interrelations between the
lower face and dimensions of the URT air space may
prove helpful in planning orthodontic treatment, with
or without teeth extraction, as well as orthognathic
surgeries.