Abstract:

Objective To establish a rat model of cleft lip and palate combined with maxillary bone defect (unilateral alveolar cleft), and investigate its stability. Methods SD rats (7 weeks old) were selected, and 4 mm×4 mm ×3 mm alveolar cleft of upper mandible on the right was prepared to establish the rat model of cleft lip and palate combined with maxillary bone defect. Model rats were divided into control group (no treatment in bone defect area, n=10) and experiment group (bone wax packing for bone defect area, n=10). Model samples were prepared immediately after operation and 4 weeks and 8 weeks after operation in two groups, three dimensional reconstruction was conducted with microcomputed tomography (MicroCT), new bone formation in bone defect area was observed and quantitively detected, and the stability of model in two groups were analysed and compared. Results MicroCT three dimensional image reconstruction illustrated that large amount of new bone filled the bone defect area 8 weeks after operation in control group, and the bone defect area significantly decreased. However, only small amount of new bone formation was found in experiment group, and the bone defect area was not significantly decreased. Quantitive analysis revealed that the percents of new bone formation 4 weeks after operation in control group and experiment group were 54.35% and 16.53%, respectively, and those of 8 weeks after operation were 93.12% and 29.30%, respectively, with significant differences between two groups（P<0.05）. Conclusion The rat model of cleft lip and palate combined with maxillary bone defect (unilateral alveolar cleft) was successfully established, and bone defect area filled by bone wax packing can significantly increase the stability of the model.

Key words: alveolar cleft, bone grafting, MicroCT