1 Conclusion:After cleft lip repair maxillary retrusion will happen.

2 But the retrusion of alveolar mandible led to chin protrusion.

3 Objective To evaluate the effects of modified vacuum-formed retainer in the treatment of mandibular retrusion.

4 Ramus height and condylar width reduced in the mandibular retrusion group, which was a result of condylar growth inhibition during adolescence.

5 Results:Both group 1 and group 2 had significant maxillary retrusion compared with group 3.

6 Results:Both complete unilateral cleft lip and palate groups had almost the same significant degree of maxillary retrusion compared with the normal control group.

7 Method In stage I treatment, rectification using a muscle stimulator plus an outward bow gag was applied to improve the condition of mandibular retrusion.