Craniofacial growth and respiration: a study on an animal model.

Aims: The aim of this study was to analyse the effects of nasal obliteration with regards to the linear dimensions of dissected hemimandibles of a homogeneous sample of young rats.

Methods: 68 pure breed male Sprague-Dawley rats, aged four weeks, were divided into four groups of 17: two control groups and two test groups. The first control group was sacrificed at the beginning of the observation period and the other one at the end. The test groups, one of which had the right nostril occluded by silicon material while the other had the left occluded, were sacrificed after eight weeks, at twelve weeks. After isolating the hemi-mandibles, four vertical and four sagittal measurements were taken; comparison was then made between the control groups and the experimental groups. The sagittal measurements are articular surface of the condyle-neck incisor (SARCIN), articular surface of the condyle-mental foramen (SARFORO), articular surface of the condyle-margo incisalis (SARMI), articular surface of the condyle-surface mesial of the first molar (SARSMM). The vertical measurements are superior condyle surface-base (SCOSUB), mesial surface of the first molar-base (SUMESM), maximum inferior arched concavity-base, (XCOARIB), maximum sigmoid notch concavity-base (XCOINSB).

Results: The sagittal and vertical measurements showed an increase in the values of the experimental group when compared to the controls.

Conclusion: An altered nasal respiration is able to influence the patterns of facial growth and in particular to induce an increase in the growth of the mandible.