Abstract: Objective To evaluate the changes of dentoskeletal and soft tissue profile of the patients with skeletal class Ⅲ after maxillary protraction with rapid expansion in the primary class Ⅲ dentition. Methods Eight patients with serious skeletal class Ⅲ, 5 males and 3 females, in the primary dentition were selected. The patients present with a concave facial profile, anterior or posterior crossbite. No apparent mandibular displacement was found in all patients. Cephalograms were taken before and after maxillary protraction with expansion. Results The maxillary was protracted significantly, whereas the mandible was positioned backward significantly, with a concomitant decrease in the skeletal facial angle. The corresponding soft tissue changes displayed significant decrease in soft tissue facial angle, the skeletal and soft tissue profile showed similar increases in lower facial height. The maxillary incisors tipped labially, while the mandibular incisors tipped lingually. Lip structure changed with increased upper lip convesity and decreased lower lip convexity, the inclination of the upper and the lower lip decrease significantly. Conclusion This treatment shows that significant dentoskeletal and soft tissue changes and improvements in dentofacial profile result from 6 months of treatment with maxillary expansion and protraction.

Key words: primary dentition occlusal, skeletal crossbite, maxillary protraction