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Updated: Jul 13, 2026
Finite Element Analysis Model for Assessing Expansion Patterns from Surgically Assisted Rapid Palatal Expansion
Published on: October 20, 2023
Long-term anteroposterior and vertical maxillary changes in skeletal class II patients treated with slow and rapid
Roberto M A Lima Filho1, Antonio C O Ruellas
1Department of Orthodontics, Universidade Federal do Rio de Janeiro, Brazil. robertomario@terra.com.br
Objective:
To evaluate a 10-year follow-up of anteroposterior and vertical maxillary changes in skeletal Class II patients treated with slow and rapid maxillary expansion methods.
Materials And Methods:
The sample consisted of 70 patients divided into two groups: (1) treated with a cervical headgear with expansion of the inner bow (CHG) and (2) using a Haas-type rapid maxillary expansion appliance in conjunction with cervical headgear (RME-CHG). The CHG group consisted of 40 patients (18 males and 22 females; average age 10.6 years at pretreatment [T1], 13.6 years at posttreatment [T2], and 23.6 years at postretention [T3]). The RME-CHG group consisted of 30 patients (14 males and 16 females; average age 10.4 years at T1, 14.0 years at T2, and 24.6 years at T3). The profiles of SNA and SN-PP angles showed no significant differences in either group at T1, T2, and T3 phases.
Results:
For the entire sample, the profile analysis between the phases showed reduction in the SNA angle from T1-T2 and an increase from T2-T3. The SN-PP angle showed an increase from T1-T2 and a decrease from T2-T3. Treatment of skeletal Class II patients with slow and rapid maxillary expansions was efficient and stable over the long-term.
Conclusions:
The profiles of SNA and SN-PP at T1, T2, and T3 achieved with slow and rapid maxillary expansions were clinically equivalent.
