This retrospective non-randomized controlled clinical trial aimed to compare the skeletal and dentoalveolar effects of two orthopedic treatment protocols for skeletal Class III malocclusion in growing patients: a conventional tooth-borne rapid maxillary expansion combined with facemask therapy, and a hybrid skeletal anchorage expander combined with chin-plate traction. Lateral cephalometric changes before and after maxillary protraction were analyzed to assess sagittal skeletal correction and dentoalveolar effects.
Skeletal Class III malocclusion is frequently associated with maxillary growth deficiency and presents significant functional and esthetic challenges. Conventional treatment using rapid maxillary expansion combined with facemask therapy is effective but limited by patient compliance and undesirable dentoalveolar effects. The introduction of skeletal anchorage devices allows the application of orthopedic forces with reduced dental compensation and extended effectiveness beyond early growth stages. This study retrospectively evaluated growing patients (CVS1-CVS3) treated with either a tooth-borne expander and facemask or a hybrid skeletal anchorage expander combined with chin-plate traction. Cephalometric variables were measured before treatment (T0) and after completion of maxillary protraction (T1) to compare skeletal and dentoalveolar changes between protocols.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
36
Bonded acrylic splint-type Hyrax expander with hooks in the maxillary canine region. Expansion activated once daily (0.25 mm). Facemask therapy initiated two weeks after expansion onset with 400 g per side of elastic traction, directed approximately 30° downward relative to the occlusal plane, worn 14-16 hours per day.
Modified Hybrid Hyrax expander supported by first molars and anchored with miniscrews placed bilaterally in a paramedian position. Expansion activated once daily (0.25 mm). Mandibular chin-plates (bollard-type or single chin-plate depending on eruption stage) were surgically inserted, and Class III elastics delivering 400 g per side were applied following a progressive loading protocol.
Change in sagittal skeletal relationship
Changes in the cephalometric angles SNA, ANB, and Wits appraisal measured on lateral cephalograms between T0 and T1
Time frame: From baseline (T0) through study completion, an average of 1 year (T1)
Cephalometric vertical skeletal changes
o Cephalometric vertical measurements from T0 to T1, using a customized cephalometric analysis based on Steiner, Tweed, and McNamara references: Mandibular plane to SN (Sella-Nasion) angle, ANS (Anterior Nasal Spine)-PNS (Posterior Nasal Spine) to Mandibular plane angle, and ANS-PNS to SN angle
Time frame: From baseline (T0) through study completion, an average of 1 year (T1)
Cephalometric dentoalveolar changes
o Upper and lower incisor inclination changes from T0 to T1 using a customized cephalometric analysis based on Steiner, Tweed, and McNamara references: U\_SN (Upper incisor to Sella-Nasion)and IMPA (Lower Incisor Mandibular Plane Angle)
Time frame: From baseline (T0) through study completion, an average of 1 year (T1)
Treatment duration
o Time elapsed between T0 and T1
Time frame: From baseline (T0) through study completion, an average of 1 year (T1)
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