Abstract: Objective To investigate the effects of bilateral intermittent nasal obstruction on the mandibular growth and development of young rats. Methods Thirty 3-weekold SD rats were randomly distributed into three groups (n=10 each). The experimental subjects were treated with single / both nostrils occluded with nose plugs, while the internal control group was left with blank treatment. The experimental subjects were sacrificed after 4 weeks and their mandibles were detached. Ten variables of mandibles were acquired based on Xrays. Results The subjects with bilateral nasal obstruction showed significant reduced mandible and femur in size compared to unilateral nasal obstruction group and control group. However, only length of mandibular body 、height of first molar in mandible and length of femur in unilateral nasal obstruction group showed significant difference compared to control group. Conclusion The bilateral intermittent nasal obstruction may retard the development of mandibles in rats.

Key words: nasal obstruction, mandible, growth and development, rat