Maxillary and Mandibular Arch Response to RME: a Multicentric Randomized Controlled Trial (6vsE)

University of Genova

Status: Completed

Conditions: Posterior Crossbite

Treatments: Procedure: Rapid maxillary expansion

Study type: Interventional

Funder types: Other

Identifiers

NCT02798822

80911110

Details and patient eligibility

About

Posterior crossbite is a common clinical condition often associated with transverse maxillary deficiency and functional mandibular shift. This frequent malocclusion is not self-correcting and can lead to the development of craniofacial asymmetries and mandibular dysfunction.

The aim of the current study was to evaluate maxillary and mandibular arch widths' response to RME when it is anchored to the upper second deciduous molars or to the upper first permanent molars and to create a decision-making protocol for RME therapy in mixed-dentition patients.

Full description

The effects of rapid maxillary expansion (RME) on the maxillary complex have been highly investigated,4 reporting a maximum maxillary intermolar and intercanine width increase of 6.7 mm and 5.3 mm,5 respectively, when RME is banded on upper first permanent molars.

Literature also reported cases of periodontal and endodontic damage on RME anchoring teeth; therefore, some authors have suggested banding RME on primary teeth and reporting also different mean intermolar (3.6-4.1 mm) and intercanine width increases (5-5.9 mm).

Few studies have investigated the changes in molar dental tipping and inclinations (on average from 3° up to 16.7°) following RME but comprised difficult (ie, barium sulfate solution) and more invasive examinations such as computed tomography and cone beam computed tomography (CBCT) Few articles concerning the indirect effects on mandibular arch following RME reported a low but statistically significant increase of lower intermolar (0.66-0.97 mm) and intercanine width (0.9 mm). Since no studies in the literature have analyzed the differences in permanent vs primary molars as anchoring teeth for RME, the decision to band the permanent deciduous molars did not follow a clinical protocol, but an individual decision was made for each patient based on clinician experience.

Enrollment: 88 patients

Sex: All

Ages: 8 to 10 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients in mixed dentition
• Unilateral posterior crossbite at least of the first permanent molar
• Upper deciduous second molars available as RME anchoring teeth

Exclusion criteria

Primary exclusion criteria

• Previous orthodontic treatment
• Hypodontia in any quadrant excluding third molars
• Inadequate oral hygiene
• Temporomandibular joint disorders
• Craniofacial abnormalities
• Secondary exclusion criteria
• Lack of records
• Need for lingual arch
• Lack of consensus
• Need for other orthodontic treatment during rapid maxillary expansion

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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88 participants in 2 patient groups

RME on upper first permanent molars

Active Comparator group

Description:

Intervention/Procedure: Rapid maxillary expansion. When RME was in situ, patients started the screw activation (Snap-lock expander screw, Forestadent, Pforzheim, Germany) of one-quarter turn a day (0.22 mm) until overcorrection was achieved (ie, the occlusal surface of the first maxillary palatal cusp contacted the occlusal surface of the mandibular first molar facial cusp), and the RME remained in place for 10 months. The screw was turned for 35 ± 6 days for Gr6, and the average treatment time was 12 ± 1.3 months.

Treatment:

Procedure: Rapid maxillary expansion

RME on upper second deciduous molars

Active Comparator group

Description:

Intervention/Procedure: Rapid maxillary expansion. When RME was in situ, patients started the screw activation (Snap-lock expander screw, Forestadent, Pforzheim, Germany) of one-quarter turn a day (0.22 mm) until overcorrection was achieved (ie, the occlusal surface of the first maxillary palatal cusp contacted the occlusal surface of the mandibular first molar facial cusp), and the RME remained in place for 10 months. The screw was turned for 41 ± 8 days, and the average treatment time was 12 ± 1.3 months.

Treatment:

Procedure: Rapid maxillary expansion