Mandibular Behavior with Slow and Rapid Maxillary Expansion in Skeletal Class II Patients - A Long-Term Study

Objective: To evaluate anteroposterior and vertical mandibular changes in skeletal class II patients treated with slow or rapid maxillary expansions at 10-year follow-up. Materials and Methods: The sample consisted of 70 patients divided into two groups, treated with (1) a cervical headgear (CHG) with expansion of the inner bow or (2) a Haas-type rapid maxillary expansion (RME) appliance in conjunction with CHG (RME-CHG). The CHG group consisted of 40 patients (18males and 22 females, with an average age of 10.6 years at pretreatment [T1], 13.6 years at posttreatment [T 2], and 23.6 years at postretention [T3]), and the RME-CHG group consisted of 30 patients (14males and 16 females with an average age of 10.4 years at T1, 14.0 years at T2, and 24.6 years at T3). Results: The profiles of SNB, B-Hor, and Pog-Hor showed significant increases for all treatment phases in both groups. The SN-Go-Gn angle showed no significant decrease from T1 to T2 and a significant decrease from T2 to T3. Conclusions: For the entire sample (CHG + RMECHG) the profile analysis between the phases showed mean increases in B-Ver and Pog-Ver for both phases.