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Clear Orthodontic Expander Versus Hyrax

Evaluating the Clinical Performance of a Novel Clear Orthodontic Expander Versus Hyrax: A Randomized Clinical Trial

Status
Recruiting
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07362160
Acronym
COE-Hyarx
Enrollment
40
Registered
2026-01-23
Start date
2026-02-01
Completion date
2027-02-01
Last updated
2026-04-22

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Malocclusion, Narrow Maxilla

Keywords

clear expander, hyrax, clinical trial, adolescent, thermoplastic material

Brief summary

This study will be conducted to evaluate the effectiveness of a clear expander fabricated from 2-mm biocompatible polyethylene terephthalate glycol (PETG) thermoforming material integrated with an expansion screw in achieving dental and skeletal expansion in adolescent patients, compared with the conventional Hyrax expander.

Detailed description

This will be a multicenter randomize clinical trial with two-arm parallel groups, and will be conducted at the Department of Orthodontics, College of Dentistry, University of Baghdad, as well as different specialized dental centers affiliated with the Iraqi Ministry of Health, and some private clinics. The sample size will be calculated based on previous studies with similar aim to measure the skeletal expansion. A minimum sample size of 17 patients was required, and in order to account for a 15% dropout, a total of 20 patients will be recruited for each group (new clear expander and hyrax expander). The amount of 2.5 mm or greater of maxillary sutural opening will be considered clinically effective. Two randomizations will be employed, one for the expander type and the other for the cleaning method of the new expander, a computer random generator will be used to develop a simple randomization with an equal allocation ratio (1:1) and without stratification. Data Collection and Measurements will be include, CBCT evaluation, Intraoral scan of the maxillary arch evaluation, overjet and overbite, CBCT-derived cephalometric images will be used to measure the maxillary mandibular plane angle, Microbial evaluation after using two different methods for cleaning the new clear expander and at the end of the treatment, the patient will be asked to fill out a questionnaire about the treatment, giving information about their experience and satisfaction during treatment. Data will be analyzed using the Statistical Package for Social Sciences for Windows, version 26.0, including Descriptive Statistics 9numbers, frequencies, percentages, mean, median, and standard deviations), Reliability Statistics (an intraclass correlation coefficient), and Inferential Statistics (Levene's test, Shapiro Wilk test, Paired samples t-test and Independent samples t-test).

Interventions

DEVICENew clear expander

All patients with a clear expander will be instructed to wear the appliance 24 hours a day, except during eating and cleaning. The expander will be activated twice daily (0.2 mm per turn). Patients will be provided with an instruction brochure and advised to use a reminder to ensure compliance. The expansion will continue until the desired amount of the maxillary arch expansion occurs when the maxillary first molars' palatal cusps occlude the lingual side of the mandibular first molar buccal cusps to overcome the expected relapse due to the elasticity of the palatal soft tissue.

The activation protocol for the Hyrax expander will be the same in all patients, twice daily (0.2 mm per turn). The expansion will continue until the desired amount of the maxillary arch expansion occurs when the maxillary first molars' palatal cusps occlude the lingual side of the mandibular first molar buccal cusps to overcome the expected relapse due to the elasticity of the palatal soft tissue.

Sponsors

University of Baghdad
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)

Masking description

As the study will be conducted in different clinics, all data collection and measurement will be completed with the investigator being masked to the allocation groups, though blinding of the operator will not be possible due to the appliance design/shape difference, and for the cleaning methods, blinding will be applied for the bacteriological specialist, and for the outcome assessor.

Intervention model description

hyrax expander clear orthodontic expander

Eligibility

Sex/Gender
ALL
Age
10 Years to 14 Years
Healthy volunteers
Yes

Inclusion criteria

1. Patients' age at the start of treatment will range from 10-14 years. 2. Unstable unilateral or bilateral posterior crossbite due to maxillary constriction. 3. The first molars are fully erupted. 4. Good oral health free from caries and periodontal problems at the start of treatment. 5. Good general health.

Exclusion criteria

1. Patients with obvious facial asymmetry. 2. Patients with orofacial cleft. 3. Patients with previous orthodontic treatment. 4. Patients with bad oral habits. 5. Patients with active periodontal disease.

Design outcomes

Primary

MeasureTime frameDescription
CBCT evaluationpre-treatment (T0) and immediately post-treatment (T1) around one to two monthsSkeletal and dentoalveolar measurements will be assessed using cone-beam computed tomography (CBCT). Skeletal measurements will include nasal width, midpalatal suture gap, and palatal height, measured in millimeters (mm). Dentoalveolar measurements will include vertical dental heights and maxillary width measured in millimeters (mm), as well as dental inclination measured in degrees (°). All measurements will be obtained from CBCT images using dedicated three-dimensional imaging analysis software.

Secondary

MeasureTime frameDescription
Intraoral scan of the maxillary arch evaluationpre-treatment (T0) and post-treatment (T1) around one to two monthsMaxillary transverse dental measurements will be assessed using a digital intraoral scan. The parameters evaluated will include intercanine width, interpremolar width, intermolar width, and intermolar transpalatal width, all measured in millimeters (mm) using three-dimensional digital dental model analysis software.
Clinical evaluationpre-treatment (T0) and immediately post-treatment (T1) around one to two monthsOverjet and overbite will be evaluated clinically using a calibrated orthodontic ruler, with measurements recorded in millimeters (mm).
Cephalometric analysispre-treatment (T0) and immediately post-treatment (T1) around one to two monthsCBCT-derived cephalometric images will be used to measure the maxillary mandibular plane angle in degrees (°) to evaluate the vertical relationship using cephalometric analysis software.
Microbial evaluationafter one month.Patients will be allocated into two groups according to the cleaning method: brushing with a toothbrush and aligner foam (China) or using Efferdent cleaning tablets (USA). Biofilm samples will be collected using sterile swabs with Amies transport medium (Boen Healthcare Co., Ltd., China). The outcome measure will be bacterial biofilm accumulation, assessed by bacteriological analysis based on bacterial colony counting, expressed as colony-forming units per milliliter (CFU/ml).
Patient satisfaction with the appliancearound one to two monthsAt the end of treatment, patient-reported experience and satisfaction will be assessed using a structured questionnaire. Responses will be recorded as questionnaire scores using a 3-point Likert-type scale.

Countries

Iraq

Contacts

CONTACTNoor FK Al-Khawaja, BDS, MSc
noor.alkhawaja@codental.uobaghdad.edu.iq+9647712222834
STUDY_CHAIRYassir A Yassir, Ph.D. (UK)

University of Baghdad

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Apr 23, 2026