Protracción maxilar - artículo

Original Article

Comparison of two protocols for maxillary protraction: bone anchors versus
face mask with rapid maxillary expansion
Lucia Cevidanesa; Tiziano Baccettib; Lorenzo Franchib; James A. McNamara, Jrc; Hugo De Clerckd
ABSTRACT
Objective: To test the hypothesis that there is no difference in the active treatment effects for
maxillary advancement induced by bone-anchoredmaxillary protraction (BAMP) and the active
treatment effects for face mask in association with rapid maxillary expansion (RME/FM).
Materials and Methods: This is a study on consecutively treated patients. The changes in
dentoskeletal cephalometric variables from start of treatment (T1) to end of active treatment (T2)
with an average T1–T2 interval of about 1 year were contrasted in a BAMP sample of21 subjects
with a RME/FM sample of 34 patients. All subjects were prepubertal at T1. Statistical comparison
was performed with t-tests for independent samples.
Results: The BAMP protocol produced significantly larger maxillary advancement than the RME/
FM therapy (with a difference of 2 mm to 3 mm). Mandibular sagittal changes were similar, while
vertical changes were better controlled withBAMP. The sagittal intermaxillary relationships
improved 2.5 mm more in the BAMP patients. Additional favorable outcomes of BAMP treatment
were the lack of clockwise rotation of the mandible as well as a lack of retroclination of the lower
incisors.
Conclusions: The hypothesis is rejected. The BAMP protocol produced significantly larger
maxillary advancement than the RME/FM therapy. (AngleOrthod. 2010;80:799–806.)
KEY WORDS: Class III malocclusion; Maxillary protraction; Bone anchors; Facial mask;
Cephalometrics

dental compensation components.1–5 To date, investigations have focused largely on treatment modalities
and outcomes, with inconsistencies in the timing,
duration, and type of treatment.5–19 The timing for
effective maxillary expansion and protraction withcombined rapid maxillary expansion and face mask
therapy remains limited to the deciduous or early
mixed dentitions,16 while maxillary protraction with
bone anchors and Class III elastics20–23 has been
successful in the late mixed or permanent dentition
phases. The present study evaluated the effects of
these two treatment modalities during the ideal timing
for maxillary protraction with eithertherapy, provided
that all observed patients in either group were
prepubertal (a requisite for an orthopedic impact on
maxillary sutural structures15,24).
Specifically, the purpose of this study on consecutively treated patients was to compare active treatment
effects in the skeletal maxillary and mandibular
structures, and dentoalveolar compensations for two
protocols for Class IIItreatment: bone-anchored
maxillary protraction (BAMP) and face mask therapy
in association with rapid maxillary expansion (RME/
FM).

INTRODUCTION
Class III malocclusions result from a spectrum of
cranial base, maxillary, and mandibular skeletal and
a
Assistant Professor, Department of Orthodontics, School of
Dentistry, University of North Carolina, Chapel Hill, NC.
b
Assistant Professor,Department of Orthodontics, University
of Florence, Florence, Italy; Thomas M. Graber Visiting Scholar,
Department of Orthodontics and Pediatric Dentistry, School of
Dentistry, University of Michigan, Ann Arbor, Mich.
c
Thomas M. and Doris Graber Endowed Professor of
Dentistry, Department of Orthodontics and Pediatric Dentistry,
School of Dentistry; Professor of Cell and DevelopmentalBiology, School of Medicine; Research Professor, Center for
Human Growth and Development, The University of Michigan,
Ann Arbor, Mich; Private practice, Ann Arbor, Mich.
d
Adjunct Professor, Department of Orthodontics, School of
Dentistry, University of North Carolina, Chapel Hill, NC; Private
practice, Brussels, Belgium.
Corresponding author: Dr Tiziano Baccetti, Department of
Orthodontics,...