Efficacy of Mini-implant Assisted Maxillary Expansion in Adolescents and Adults

Official title

Efficacy of Mini-Implant-Assisted Maxillary Expansion on Late Adolescents and Adults and Its Effects on Nasal Permeability and Airway Volume Using Three Different Activation Protocols: A Randomized Controlled Trial (MARPE_1)

Overview

Transverse maxillary deficiency is a common orthodontic issue, affecting around 10% of adults. Late adolescents and adults often require more force to expand the midpalatal suture due to its increased interdigitation. This study aims to assess the effectiveness of MARPE in this demographic and determine the best activation protocol for non-surgical maxillary expansion using mini-screw-supported appliances. Additionally, the study will evaluate the effectiveness of MARPE on nasal permeability and airway volume.

Detailed description

The study design comprised a three-arm, parallel-group randomized controlled trial (RCT) conducted at the Orthodontics clinic of Brussels University Hospital. Patients were randomly allocated into one of three groups:

1. Continuous rapid activation protocol: Patients received one activation of 0.17 mm per day until reaching the clinical goal. 2. Continuous slow activation protocol: Patients underwent two activations (0.33 mm) per day for the first 7 days, followed by one turn forward every third day (0.17 mm / 3 days). 3. Force-controlled polycyclic protocol: Patients underwent two activations (0.33 mm) per day for the first 7 days. Then, the hex nut was turned 6 sides backward, followed by 6 sides forward after 15 minutes. Additionally, the device was activated by 0.17 mm every third day.

Intervention:

All patients underwent maxillary expansion with MARPE. Four orthodontic mini-screws were inserted under local anesthesia using a surgical guide and motor. Surgical incision was not required, and predrilling was performed if necessary. The MARPE remained in place for 12 months after expansion to allow bone remodeling in the midpalatal suture. Fixed straight-wire treatment commenced 2 months after expansion termination. Patients underwent retention check-ups at 6 and 12 months post-expansion, and expansion screws and mini-screws were removed after 12 months or before orthognathic surgery, if applicable.

The specific aims of the study were to evaluate the success rate of nonsurgical maxillary expansion, compare the efficacy of the three activation protocols, assess and compare complications, analyze the correlation between success rate and Midpalatal Suture Maturation Stage (MPS), age, and sex, and measure nasal permeability variation using anterior rhinomanometry.

Interventions

• Device Mini-implants assisted maxillary expansion
  The intervention involved the placement of orthodontic mini-screws in the patient's palate, varying in diameter from 2 to 2.3 mm and in length from 11 to 15 mm. After mini-screw insertion, another intraoral scan was taken for the fabrication of the appliance. Approximately three weeks later, the expander was placed in the patient's palate, and maxillary expansion was initiated immediately afterward according to the chosen protocol.

Primary outcome measures

• MPSM: mid-palatal suture middle molars [Time frame: up to 6 months]
• ANS-ANS [Time frame: up to 6 months]
• PNS-PNS [Time frame: up to 6 months]
• UID [Time frame: up to 6 months]
• ZMA [Time frame: up to 6 months]
• LID: [Time frame: up to 6 months]
• NCW: nasal cavity width [Time frame: up to 6 months]
• MSW: midpalatal suture width [Time frame: up to 6 months]
• IMW: intermolar width [Time frame: up to 6 months]
• IPW: interpremolar width [Time frame: up to 6 months]

Secondary outcome measures (8)

• RT resistance total [Time frame: up to 6 months]
• NCV: nasal cavity volume [Time frame: up to 6 months]
• RMSV : right maxillary sinus volume [Time frame: up to 6 months]
• LMSV : left maxillary sinus volume [Time frame: up to 6 months]
• NPV nasopharynx volume [Time frame: up to 6 months]
• OPV oropharynx volume [Time frame: up to 6 months]
• OMCSA: oropharynx minimum cross-sectional area [Time frame: up to 6 months]
• AV: Accumulated volume [Time frame: up to 6 months]

Eligibility criteria

Inclusion criteria

• from the age of 16 onwards
• who presented with transverse maxillary discrepancy (unilateral, bilateral, anticipated, or constriction without crossbite).

Exclusion criteria

• history or presence of maxillofacial surgery, cleft lip and palate, craniofacial anomalies or syndromes, congenital tooth anomalies, and periodontal disease.
• Patients who had previously palatal expansion were excluded also.
• Presence of anatomic or pathological obstacle of the palatal mini-screw insertion (impacted tooth, tumor.)
• refusal of study participation

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Treatment

Study locations

Belgium · 2 centers

• Route de Lennik 900 — Anderlecht
• service dentaire et d'orthodontie de l'hopital université de bruxelles (HUB) — Anderlecht

Identifiers

NCT: NCT06449014 · Erasme_MARPE_1

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗