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NCT Number: NCT07362160

Clear Orthodontic Expander Versus Hyrax

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.

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Key information

Conditions

Malocclusion Narrow Maxilla Stomatognathic Diseases Tooth Diseases

Age range

10 year–14 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Baghdad/Collage of Dentistry

Baghdad, Al-Rusafa, Bab Al-moadham, Iraq

Location status: Recruiting

Location contact

Noor FK Al-Khawaja, BDS, MSc

CONTACT

[email protected]

+9647712222834

About this study

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).

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

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

Exclusion criteria

  • Patients with obvious facial asymmetry.
  • Patients with orofacial cleft.
  • Patients with previous orthodontic treatment.
  • Patients with bad oral habits.
  • Patients with active periodontal disease.

Treatment and study plan

New clear expander

Device

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.

Hyrax expander

Device

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.

Primary outcomes

  1. CBCT evaluation

    Time frame: pre-treatment (T0) and immediately post-treatment (T1) around one to two months

    Skeletal 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 outcomes

  1. Intraoral scan of the maxillary arch evaluation

    Time frame: pre-treatment (T0) and post-treatment (T1) around one to two months

    Maxillary 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.

  2. Clinical evaluation

    Time frame: pre-treatment (T0) and immediately post-treatment (T1) around one to two months

    Overjet and overbite will be evaluated clinically using a calibrated orthodontic ruler, with measurements recorded in millimeters (mm).

  3. Cephalometric analysis

    Time frame: pre-treatment (T0) and immediately post-treatment (T1) around one to two months

    CBCT-derived cephalometric images will be used to measure the maxillary mandibular plane angle in degrees (°) to evaluate the vertical relationship using cephalometric analysis software.

  4. Microbial evaluation

    Time frame: after 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).

  5. Patient satisfaction with the appliance

    Time frame: around one to two months

    At 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.

Study contacts

Contact information is provided by the study sponsor or research team.

Noor FK Al-Khawaja, BDS, MSc

CONTACT

[email protected]

+9647712222834

Sponsors and collaborators

Lead sponsor

University of Baghdad

Other

Registry information

Official study title

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

Acronym: COE-Hyarx

Important dates

Study start
2026
Primary completion
2026
Study completion
2027
First posted
Jan 23, 2026
Registry last updated
Apr 22, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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