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.


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 (18 males and 22 females, with an average age of 10.6 years at pretreatment [T(1)], 13.6 years at posttreatment [T(2)], and 23.6 years at postretention [T(3)]), and the RME-CHG group consisted of 30 patients (14 males and 16 females with an average age of 10.4 years at T(1), 14.0 years at T(2), and 24.6 years at T(3)).


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 T(1) to T(2) and a significant decrease from T(2) to T(3).


CONCLUSIONS
For the entire sample (CHG + RME-CHG) the profile analysis between the phases showed mean increases in B-Ver and Pog-Ver for both phases.
Lima Filho
Roberto M A
RM
robertomario@terra.com.br
de Oliveira Ruellas
Antonio Carlos
AC
D000293:Adolescent; D002508:Cephalometry; D002648:Child; D005115:Extraoral Traction Appliances; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008334:Mandible / Q000254:growth & development*; D010155:Palatal Expansion Technique / Q000295:instrumentation*; D012189:Retrospective Studies; D016896:Treatment Outcome