Dental

ORIGINAL ARTICLE Sagittal changes after maxillary protraction with expansion in Class III patients in the primary, mixed, and late mixed dentitions: A longitudinal retrospective study
Marc Saadia, DDS, MS,a and Edgar Torres, DDS,b Mexico City, Mexico The purpose of this study was to determine the sagittal response of Class III patients in the primary, mixed, and late mixed dentition phasesfitted with a protraction mask and expansion. The before-and-after cephalometric records of 112 patients divided by gender were analyzed at age groups 3 to 6, 6 to 9, and 9 to 12 years to assess the maxillary, mandibular, and intermaxillary sagittal changes. Data were correlated by means of paired t tests and Scheffé multiple contrasts. The study showed: (1) descriptive statistics and thebefore-and-after results in males and females in the different age groups; (2) the changes in males and females, disregarding age; and (3) the changes at the different ages, disregarding gender. Results show no significant differences between males and females in most of the angular and linear measurements at different ages. Greater significant changes were seen in patients treated in the primary and mixeddentition phases. Females showed highly significant changes in most linear and angular measurements between the ages of 3 and 6 years (P < .0001) compared with males (P < .05 ) at the same age. Significant changes were seen in the angle between the anterior part of the maxilla and the base of the skull (SNA), the maxillary depth, and the facial convexity angles, being more active in females thanmales. In contrast, the angle between the anterior part of the mandible and the base of the skull (SNB) showed no significant changes in all age groups, with the exception of males between 3 and 6 years. Even if correction can be achieved in all age groups, we recommend that treatment be started as soon as the diagnosis is made and cooperation allows for it. Young patients show greater and fasterresults in less time. Esthetics are greatly enhanced, compliance is improved, and the possible psycho-social scars can be greatly reduced. (Am J Orthod Dentofacial Orthop 2000;117:669-80)

he management of Class III malocclusion remains one of the most challenging problems confronting the practicing dentist. Treatments in the permanent dentition can be relatively easy when the problem is confined tothe alveolar bone. However, when the deformity affects basal bones, such as with a deficient maxilla, an overgrowth of the mandible, or a combination of both, then our treatment options are greatly reduced. But when the problem is diagnosed by the parent or the dentist in the primary dentition, just to observe it worsen with time stimulated us to seek some alternatives.
LITERATURE REVIEW

TFor a long time, practitioners avoided early treatment because they believed the condition was caused by a mandibular overgrowth; since mandibular growth
From the Department of Pediatric Dentistry, Technological University of Mexico. aProfessor. bProfessor. Work performed in partial fulfillment of the requirements for master in science in Pediatric Dentistry and Orthodontics at the TechnologicalUniversity of Mexico. Reprint requests to: Dr Marc Saadia, Prado Sur 290, Lomas de chapultepec, Mexico 11000 D.F., Mexico; e-mail, msaadia@data.net.mx Copyright © 2000 by the American Association of Orthodontists. 0889-5406/2000/$12.00 + 0 8/1/103773 doi.10.1067/mod.2000.103773

could not be controlled, surgery was inevitable. They relied on cephalometric analyses that were not designed foryoung children. For example an ANB angle of 3° positive could mean a Class III malocclusion in a 4year-old vertical patient. It also was often difficult to identify the jaw that contributed to the Class III malocclusion. These variables made clinicians feel insecure, and as a result they preferred to delay treatment. The developing Class III problem generally irreversibly affected the dentofacial...