Mandibular response after rapid maxillary expansion in class II growing patients: a pilot randomized controlled trial

Abstract

BackgroundThe aim of this pilot randomized controlled trial (RCT) was to evaluate the sagittal mandibular response induced by rapid maxillary expansion (RME) therapy in mixed dentition patients with class II malocclusion, comparing the effects of bonded RME and banded RME with a matched untreated class II control group.MethodsThis RCT was designed in parallel with an allocation ratio of 1:1:1. The sample consisted of 30 children with a mean age of 8.1 ± 0.6 years who were randomly assigned to three groups: group 1 treated with bonded RME, group 2 treated with banded RME, and group 3 the untreated control group. All patients met the following inclusion criteria: early mixed dentition, class II molar relationship, transverse discrepancy ≥ 4 mm, overjet ≥ 5 mm, and prepubertal skeletal maturity stage (CS1–CS2). The expansion screw was activated one quarter of a turn per day (0.25 mm) until overcorrection was reached. For each subject, lateral cephalograms and plaster casts were obtained before treatment (T1) and after 1 year (T2). A randomization list was created for the group assignment, with an allocation ratio of 1:1:1. The observer who performed all the measurements was blinded to group assignment. The study was single-blinded in regard to statistical analysis.ResultsRME was effective in the correction of maxillary deficiency. Class II patients treated with both types of RME showed no significant improvement of the anteroposterior relationship of the maxilla and the mandible at both skeletal and occlusal levels. The acrylic splint RME had significant effects on reducing the skeletal vertical dimension and the gonial angle.ConclusionsThe orthopedic expansion did not affect the sagittal relationship of class II patients treated in the early mixed dentition when compared with the untreated control group. Additional studies with a larger sample are warranted to elucidate individual variations in dento-skeletal mandibular response to the maxillary expansion protocol in class-II-growing patients.Trial registration ClinicalTrials.gov NCT03159962.

Three-Dimensional Evaluation of Slow Maxillary Expansion with Leaf Expander vs. Rapid Maxillary Expansion in a Sample of Growing Patients: Direct Effects on Maxillary Arch and Spontaneous Mandibular Response

“…The maxillary deficit does not self-correct during the growth, thus, slow maxillary expansion (SME) or rapid maxillary expansion (RME) could be performed with the intent to correct it. As reported by several authors, widening the maxilla with maxillary expansion often leads to spontaneous forward posturing and to spontaneous expansion of the mandible [9][10][11][12]. This is because the palatal expansion acts on the balance of forces between the tongue and cheek on lower arch.…”

Systematic review of major considerations of rapid maxillary expansion

“…5 Thus, the most accepted age for performing NSARME varies widely according to the literature, being proposed for patients with a maximum age of 14 years in women and 16 years in men, according to. 6 Some authors were successful with the age range between 15 and 54 years, using the NSARME technique with a Haas expander in a 19-year-old patient, contradicting the authors who affirmed the efficacy of the technique only in patients with incomplete bone maturation. 1,9 Therefore, there is no consensus in the literature regarding a fixed age for NSARME indication.…”

“…4,5 From the Haas dental orthodontic expander, many others were developed, including the modified Haas and the Hyrax apparatus. 6 The latter is a supported dento expander that leads to greater posterior dentoalveolar inclinations, if compared as Haas expander. 6 In this scenario, the choice of a breaker for maxillary correction is important and can be selected by the main predictors such as bone structure, alveolar processes, the presence or absence of dental elements, the hygiene of the patient, the dentition to be mixed or not, the need for a greater anterior or posterior increase, dentoalveolar inclinations, interdental distances, vertical destabilization and age.…”

“…6 The latter is a supported dento expander that leads to greater posterior dentoalveolar inclinations, if compared as Haas expander. 6 In this scenario, the choice of a breaker for maxillary correction is important and can be selected by the main predictors such as bone structure, alveolar processes, the presence or absence of dental elements, the hygiene of the patient, the dentition to be mixed or not, the need for a greater anterior or posterior increase, dentoalveolar inclinations, interdental distances, vertical destabilization and age. 1,7 Although it is a satisfactory procedure in children and adolescents, the technique of rapid non-surgical expansion presents failures in adult patients, because with skeletal maturation, the response to expansion forces is diminished.…”

Correction to: Mandibular response after rapid maxillary expansion in class II growing patients: a pilot randomized controlled trial

“…In the publication of this article [ 1 ] there is an error in the Methods section. This has now been included in this correction.…”