Hypoplasia of the middle third of the face -a morphological study.

The aim of this investigation was to examine the morphological characteristics of patients diagnosed as having hypoplasia of the middle of the face. The study group consisted of lateral skull X-rays of 31 patients, aged 8.4-18.1 years, with hypoplasia of the middle third of the face. A control group of 31 patients matched according to age and sex was used. The study group showed the following significant differences: short anterior cranial base, small cranial base angel, reduced sagittal development of the nose, straight profile, retrognathic maxilla, short maxilla, reduced sagittal depth of the nasopharynx and reduced vertical growth of the maxilla. The results indicate a reduction in dimensions of the entire nasal airway which, it is suggested, could have an adverse effect on nasal breathing. In addition, correlation analyses for the mandibular plane angle (ML/NSL) in relation to variables of importance in mode of breathing 1) the sagittal depth of the nasopharynx, and 2) the inclination of the nasal bone, have confirmed earlier studies showing that a change in the mode of breathing can affect the development of the entire craniofacial complex. The clinical aspects of these findings are discussed.