Methods: Twelve Wistar rats were used in this experiment. When they were 5 weeks old, the rats were randomly divided into 2 groups with equal number of gender. One group was removed the maxillary 1-3 molars served as P1 while the other group was no extraction served as the control; both groups were supplied with MF powder diet. The P1 rats were mated at 10 weeks old for the next generation (F1). At the age of 20 weeks, both groups were weighted and sacrificed in the CO2 chamber. The mandibles of rats were dissected and measured the length of body,ramus and angle. The F1 was treated in the same way as P1.
Results: The body weight of the extraction rats (P1 male 211.3±6.7g, female 202.5±8.3g; F1 male 208.3±5.5g, female 200.5±8.1g) were lower than the control group (male 277±7.7g, female 267±8.9g) at 20 weeks old. The ramus of mandible of the extraction rats (P1 male 9.84±0.37mm, female 9.48±0.38mm; F1 male 9.68±0.34mm, female 9.34±0.27mm) were shorter than the control group (male 12.54±0.33mm, female 12.1±0.28mm). The length of mandible of the extraction rats (P1 male 24.29±0.74mm, female 23.12±0.58mm; F1 male 24.11±0.64mm, female 23.24±0.42mm) were shorter than the control group (male 27.89±0.75mm, female 26.79±0.67mm). The mandible angle of the extraction group (P1 male 90.5±0.80°, female 91.0±0.75°; F1 male 91.25±0.85°, female 90.5±0.75°) were larger than the control group (male 80.5±0.85°, female 81.5±0.70°).
Conclusions: The reduction of mastication function decrease the body weight and mandible length, expanded the mandible angle of the rats. Masticatory dysfunction of the first generation did affect the body and mandible growth of progeny.
Keywords: Animal, Mastication and mandible