This study evaluates the dentoskeletal effects of the expander with differential opening in orthodontic patients in the mixed dentition. Half of participants will undergo rapid maxillary expansion (RME) using the expander with differential opening, while the other half will undergo RME using the conventional Hyrax expander.
Recently, a rapid maxillary expander with differential opening was developed aiming to treat maxillary constrictions greater in the anterior region compared to the posterior region of the maxillary dental arch. The aim of this study is to evaluate the dentoskeletal effects of the expander with differential opening in orthodontic patients in the mixed dentition. Material and methods: Fifty patients with maxillary constriction in the mixed dentition will be prospectively and randomly allocated in one of two study groups. The experimental group will comprise 25 patients who will be submitted to rapid maxillary expansion with the expander with differential opening. The control group will be comprised by 25 individuals who will undergo rapid maxillary expander with the Hyrax expander. Digital dental models will be acquired immediately pre-expansion (T1) and six months post-expansion (T2). The Orthoanalyzer™ software will be used to measure maxillary and mandibular widths, arches perimeter, arches lengths, palatal depth, and inclinations of maxillary and mandibular canines and permanent first molars. The intergroup and interphase comparisons will be analyzed using t tests and paired t tests, respectively (p\<0.05).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
50
Twenty-five patients will be submitted to rapid maxillary expansion using the expander with differential opening. Appliance anchorage will be provided by bands adapted either on the maxillary first permanent molars or on the second deciduous molars and circumferential clamps will be bonded to the maxillary deciduous canines. If the maxillary second deciduous molars will be banded, a lingual extension wire will be placed in the partially erupted maxillary first permanent molars. Both anterior and posterior screws will be activated with a complete turn a day during 6 days. Then, only the anterior screw will be additionally activated for 4 more days. After the active period of RME, the screws will be fixed with acrylic resin and the appliance will be kept as a retainer for 6 months.
Twenty-five patients will undergo rapid maxillary expansion using conventional Hyrax expander. Bands will be adapted either on the maxillary first permanent molars or on second deciduous molars and circumferential clamps will be bonded to the maxillary deciduous canines. Similarly to the experimental group, a lingual extension wire will be placed in the partially erupted maxillary first permanent molars if the maxillary second deciduous molars will be banded. The expander screw will be activated with a complete turn a day during 6 days. After the expansion active phase, the screw will be fixed with acrylic resin and the appliance will be kept in the dental arch as a retainer for 6 months.
University of São Paulo
Bauru, São Paulo, Brazil
RECRUITINGMaxillary and mandibular inter-first permanent molar distances
Time frame: 6 months
Maxillary and mandibular inter-second deciduous molar distances
Time frame: 6 months
Maxillary and mandibular inter-first deciduous molar distances
Time frame: 6 months
Maxillary and mandibular inter-deciduous canine distances
Time frame: 6 months
Maxillary and mandibular dental arches perimeters
Time frame: 6 months
Maxillary and mandibular dental arches lengths
Time frame: 6 months
Palatal depth
Time frame: 6 months
Inclination of maxillary and mandibular first permanent molars
Time frame: 6 months
Inclination of maxillary and mandibular deciduous canines
Time frame: 6 months
Amount of interincisor diastema
Time frame: 10 days
Amount of differential expansion on the maxillary and mandibular dental arches
Time frame: 6 months
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