Maxillary expansion, constriction, and protraction through facial mask to correct anterior crossbite: case report

Introduction: Maxillary protraction with or without rapid maxillary expansion (RME) is the therapy of choice for early skeletal Class III malocclusion caused by maxillary deficiency. Objective: To report a clinical case of rapid maxillary expansion and constriction with maxillary protraction in boy with skeletal Class III at mixed dentition. Report: A boy aged 9 years and 3 months, with skeletal Class III malocclusion and anterior crossbite of -3mm was treated with a protocol of maxillary expansion and constriction by Hyrax expander associated with maxillary protraction by Petit facial mask. For 4 days, the expander was opened by 2/4 turn in the morning and closed by 2/4 turn in the evening. Elapsed that period, the boy wore the face mask delivering 500N force, for 14 hours per day, for 3 months. After overcorrection, the mask was used during the night delivering a 300N force. Results: The treatment achieved a 2.5mm overjet, with good maxilla-mandible transversal relationship and good facial profile. Conclusion: The protocol of maxillary expansion and constriction followed by maxillary protraction with Petit mask was effective to correct the anterior crossbite and the early skeletal Class III malocclusion caused by anterior-posterior maxillary deficiency.