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Orthodontic RelapseNCT07659041

Effectiveness, Patient Acceptance, and Cost Estimation of 3D-printed Retainer Compared to Hawley Retainer in Expansion Case: a Randomized Controlled Trial

A study testing 3D printed retainer and Hawley retainer in people with Orthodontic Relapse and Retention in Orthodontic, run by National University of Malaysia at 3 sites in Malaysia.

Not yet recruiting

Opening soon. The study is approved but enrolment has not started yet. Sites may already take enquiries.

Sites and contacts
Official record
Search all trials

Trial summary

Expansion of the arches is generally considered highly unstable and prone to relapse regardless of the type of expansion. Retention appliances play a vital role in preserving these changes. Hawley retainer users often avoid wearing them due to speech difficulties and less aesthetic appeal. Read more about this study

Who is it for?
Ages 16 years and olderHealthy volunteers can take part
Conditions the study is for
Orthodontic Relapse, Retention in Orthodontic
What is being tested?
3D printed retainer and Hawley retainer
Type of treatment
Medical device
Could I receive a placebo?
No, everyone receives an active treatment
How many people
28 participants
Where
3 sitesMalaysia
Study dates
Jun 2026to Dec 2027
Phase
Interventional
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 16 years and older
  • All sexes
  • Healthy volunteers accepted
  • Child, Adult, Older adult

Who may be able to join

  • Patients aged 16 years or older at the time of debonding
  • Treatment plan of extraction or non-extraction followed by straight wire appliances in the upper arch only or both arches
  • Undergone expansion treatment in the upper arch causing an arch width increase of 3-10mm, either using a Quadhelix, expansion with archwires, or URA with midline screw
  • Had pretreatment dental cast
  • Had no chronic medical condition.

Who cannot join

  • Cleft lip and palate
  • Chronic medical conditions
  • Broken teeth or bubbles on study model at site of measurement.

Trial locations and contacts

3 sites in 1 country. Contact the study team or a site near you to ask about taking part.

Asma Ashari, BDS Adel, MClinDent Lon, MOrth contact

+603 8921 5555

asmaashari@ukm.edu.my

ALIZAE MARNY FADZLIN SYED MOHAMED contact

+6038921 5555

alizaemarny@ukm.edu.my

Malaysia3 sites
  • National University Of Malaysia

    Kuala Lumpur, Kuala Lumpur, 50300

    Fakulti pergigian UKM, +6039289 7741, asmaashari@ukm.edu.my

    Mei Ling Cheng

  • University Malaya

    Kuala Lumpur, Kuala Lumpur, 50603

    May Nak Lau, +60379674802, minalau@um.edu.my

    Zhang Yi Tan

  • University Teknologi Mara Selangor branch

    Sungai Buloh, Selangor, 47000

    Nik Mukhriz Nik Mustapha, +6036126 6103, nikmukhriz@uitm.edu.my

    Siti Nor Hafizah Salehun

Other trials in Malaysia

About this study

Expansion of the arches is generally considered highly unstable and prone to relapse regardless of the type of expansion. Retention appliances play a vital role in preserving these changes. Hawley retainer users often avoid wearing them due to speech difficulties and less aesthetic appeal. They are also more prone to breakage, costlier, and require more labour. Despite the relatively recent introduction of 3D-printed retainers, they offer potential advantages in orthodontics, including the accuracy of digitally scanned images, reduced labour and material costs, and improved patient comfort. While 3D-printed retainers are quite new, most studies focus on laboratory testing of their mechanical properties, there is limited evidence directly comparing their effectiveness in retaining arch width increases, patient acceptance, and cost estimation. This knowledge gap creates uncertainty about the optimal choice of retainer for long-term stability, necessitating a comparative assessment of their performance. This study addresses this knowledge gap by evaluating the retention of arch width increases achieved using Hawley retainers versus 3D-printed retainers

Read the detailed description

Maxillary dentoalveolar expansion is a procedure to correct transverse discrepancies between the maxillary and mandibular arches by applying forces to widen the maxillary arch. This procedure is inherently unstable and is susceptible to relapse. While Hawley retainers (HR) have served as the established standard for retention after maxillary expansion, recent studies have shown that modified thermoforming retainers can be as effective as HR. The emergence of computer-aided design and computer-aided manufacturing (CAD-CAM) and three-dimensional (3D) printing technology has significantly streamlined fabricating appliances and prostheses. 3D printing material is more rigid, with superior compression and tensile strength. Thus, a normal shape 3D-printed retainer may be a viable choice for the retention of maxillary expansion. A recent systematic review highlighted a critical gap in knowledge regarding the long-term clinical efficacy and durability of 3D-printed retainers. Thus, the present study aimed to address this research gap by investigating the long-term clinical effectiveness, patient acceptance, and cost estimation of 3D-printed retainers in expansion cases. This study will be carried out as a multicentre prospective randomized controlled clinical trial (RCT) conducted at Universiti Kebangsaan Malaysia (UKM), Universiti Malaya (UM), and Universiti Teknologi MARA (UiTM). Orthodontic patients who fulfil the inclusion criteria will be randomly allocated into the HR or 3D-printed retainer groups. Dental casts of patients will be measured at intercanine width (ICW), inter-premolar width (IPMW), inter-first molar mesiobuccal cusp width 1 (IFMW1), and inter-first molar distobuccal cusp width 2 (IFMW2) for both groups at debond(T0), 3(T1), 6(T2), and 12(T3). The outcome assessor and data analyst will be blinded to the retention method. The researcher will evaluate the patient's acceptance at T2 \& T3 and conduct a cost analysis at T1 post-debond. The findings of this study will contribute valuable data to the field of orthodontics, aiding clinicians in determining the most effective long-term retention strategy for patients who have undergone maxillary dentoalveolar expansion.

Being tested
3D printed retainer, Hawley retainer
Keywords
orthodontic, 3D printed retainer

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • 3D printed retainerDevice

    3D-printed retainer Using Nextdent Orthoflex resin

    Standard design of 3D printed retainer:

    • Monolithic design (no wires)
    • Thickness 0.8mm-1.0 mm
    • Fully cover the teeth and part of the gingiva (1-2mm)
    • Undercut block - 0.25-0.5mm
  • Hawley retainerDevice

    Hawley retainers have served as the established standard for retention after maxillary expansion. Standard design of Hawley Retainer: - Labial bow (0.8mm hard stainless steel) from canine to canine - Adam clasp on the molar (0.7mm hard stainless steel) - acrylic baseplate (2-3mm thickness) .

Study groups in NCT07659041
Study groupRoleWhat they receive
Hawley retainerActive comparatorA screening will be done to select suitable patients for the study. Only patients who fulfil the criteria will be invited to participate in this study. Following informed consent, eligible subjects will be randomly allocated into one of two groups wither hawley retainer or 3D printed retainer. Fabrication of Hawley retainers will be done using a standardized design across all centres.
Receives: Device: Hawley retainer
3D printed retainerExperimentalA screening will be done to select suitable patients for the study. Only patients who fulfil the criteria will be invited to participate in this study. Following informed consent, eligible subjects will be randomly allocated into one of two groups wither hawley retainer or 3D printed retainer. Fabrication of 3d printed retainers will be done using a standardized design at one main centres by one technician using Nextdent Orhtoflex Resin.
Receives: Device: 3D printed retainer

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Retention of the maxillary expansion

    1. Subjects will be scheduled for follow-up at T1-T3 after the initiation of retention wear. During these visits, impressions will be acquired with alginate impression material, and ICW, IPMW, IFMW1, and IFMW2 will be measured intraorally and on dental casts.
    2. Calibrated researchers will collect the study models, and the ID and intervention will be covered by opaque tape once they are ready for measurement. Only one dental cast at a time will be picked out of its box without showing any previous measurements. Two dental casts from the same patient will not be measured in connection. Due to the prospective nature of the study, it was inconvenient to anonymize dental casts from the start of the study.
    3. Intraclass correlation coefficient (ICC) will be done within and between researchers one week after the T0.

    Measured: 12 months

Secondary outcomes (2)
  1. Patient acceptance

    Subjects will be given and asked to complete a questionnaire on patient acceptance (see attachment) at 6 and 12 months post-debond. The Questionnaire has been validated and published by (Saw et al. 2025). It uses a Visual Analogue Scale (VAS) to ask six questions related to subject acceptance of orthodontic retainers in fitting, speech, appearance, oral hygiene, durability, and comfort.

    Refer to Attachment 1 (Malay version) and Attachment 2 (English Version) for the questionnaires.

    Measured: 12 months

  2. cost estimation

    To estimate and compare the costs associated with the implementation and provision of 3D-printed retainers between clinics with existing in-house 3D-printing facilities and clinics planning to acquire 3D-printing services. The analysis will include direct costs such as equipment acquisition, materials, software, maintenance, laboratory procedures, and staff chairside time.

    Measured: 6 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted22 Jun 2026
  2. Study startJun 2026 (estimated)
  3. Primary completionDec 2027 (estimated)
  4. Study completionDec 2027 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Other
Allocation
Randomised
Intervention model
Parallel groups
Model description
This study will be a multicentre prospective randomized controlled clinical trial conducted at Universiti Kebangsaan Malaysia (UKM), Universiti Malaya (UM), and Universiti Teknologi MARA (UiTM). A screening will be done to select suitable patients for the study. Only patients who fulfil the criteria will be invited to participate in this study. Participants will be approached in the dental chair once deemed suitable and given 5-10 minutes to decide on study participation. Consent will be gathered from the patients or the carer if the patient is below 18. Following informed consent, eligible subjects will be randomly allocated into one of two groups: Group 1: Hawley retainer. Group 2: 3D-printed retainer Dental casts of patients will be measured at intercanine width (ICW), inter-premolar width (IPMW), inter-first molar mesiobuccal cusp width 1 (IFMW1), and inter-first molar distobuccal cusp width 2 (IFMW2) for both groups at debond(T0), 3 (T1), 6(T2), and 12months(T3).
Masking
Single blind
Who is masked
Outcomes assessor
Enrolment
28 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07659041
Sponsor's protocol ID
JEP 2025-630
Other IDs
JEP 2025-630
Status last verified
Jun 2026
First submitted
8 Jun 2026
Last updated
22 Jun 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Undecided: Only data relevant to the study analyses will be provided. All personal identifiers and information that could reveal participant identity will be removed to protect confidentiality and comply with ethical requirements.

Publications

  • Firlej M, Zaborowicz K, Zaborowicz M, Firlej E, Domagala I, Pieniak D, Igielska-Kalwat J, Dmowski A, Biedziak B. Mechanical Properties of 3D Printed Orthodontic Retainers. Int J Environ Res Public Health. 2022 May 9;19(9):5775. doi: 10.3390/ijerph19095775.

    PubMed 35565167
  • Hichens L, Rowland H, Williams A, Hollinghurst S, Ewings P, Clark S, Ireland A, Sandy J. Cost-effectiveness and patient satisfaction: Hawley and vacuum-formed retainers. Eur J Orthod. 2007 Aug;29(4):372-8. doi: 10.1093/ejo/cjm039.

    PubMed 17702797
  • Naeem OA, Bencharit S, Yang IH, Stilianoudakis SC, Carrico C, Tufekci E. Comparison of 3-dimensional printing technologies on the precision, trueness, and accuracy of printed retainers. Am J Orthod Dentofacial Orthop. 2022 Apr;161(4):582-591. doi: 10.1016/j.ajodo.2021.03.016.

    PubMed 35337648
  • Tsoukala E, Lyros I, Tsolakis AI, Maroulakos MP, Tsolakis IA. Direct 3D-Printed Orthodontic Retainers. A Systematic Review. Children (Basel). 2023 Apr 3;10(4):676. doi: 10.3390/children10040676.

    PubMed 37189925
  • Saw ZK, Yuen JJX, Ashari A, Ibrahim Bahemia F, Low YX, Nik Mustapha NM, Lau MN. Forward-backward translation, content validity, face validity, construct validity, criterion validity, test-retest reliability, and internal consistency of a questionnaire on patient acceptance of orthodontic retainer. PLoS One. 2025 Jan 3;20(1):e0314853. doi: 10.1371/journal.pone.0314853. eCollection 2025.

    PubMed 39752631
  • Nakornnoi T, Bunjerdjin P, Santiwong P, Sipiyaruk K, Neoh SP, Chintavalakorn R. The Influence of Thickness on the Mechanical Behaviors of 3D Printing Resins for Orthodontic Retainers. Int J Biomater. 2024 Jun 25;2024:7398478. doi: 10.1155/2024/7398478. eCollection 2024.

    PubMed 38957572
  • Ashari A, Xian L, Syed Mohamed AMF, Wahab RMA, Kit YC, Tata MD, Sinnasamy S, Kuppusamy E. One-year comparative assessment of retention of arch width increases between modified vacuum-formed and Hawley retainers. Angle Orthod. 2022 Mar 1;92(2):197-203. doi: 10.2319/050921-363.1.

    PubMed 34797378
  • Ashari A, Nik Mustapha NM, Yuen JJX, Saw ZK, Lau MN, Xian L, Syed Mohamed AMF, Megat Abdul Wahab R, Yeoh CK, Deva Tata M, Sinnasamy S. A two-year comparative assessment of retention of arch width increases between modified vacuum-formed and Hawley retainers: a multi-center randomized clinical trial. Prog Orthod. 2022 Aug 26;23(1):40. doi: 10.1186/s40510-022-00424-5.

    PubMed 36018418
  • Stoev YY, Uzunov TT, Stoyanova NS, Grozdanova-Uzunova RG, Kosturkov DN, Taneva IK. Mechanical properties of materials for 3D printed orthodontic retainers. Folia Med (Plovdiv). 2023 Dec 31;65(6):986-992. doi: 10.3897/folmed.65.e107299.

    PubMed 38351789
  • Neoh SP, Khantachawana A, Chintavalakorn R, Santiwong P, Srikhirin T. Comparison of physical, mechanical, and optical properties between thermoplastic materials and 3-dimensional printing resins for orthodontic clear retainers. Am J Orthod Dentofacial Orthop. 2025 Jan;167(1):95-109.e1. doi: 10.1016/j.ajodo.2024.06.010.

    PubMed 39709226

Questions about this trial

What is this clinical trial studying?

A study testing 3D printed retainer and Hawley retainer in people with Orthodontic Relapse and Retention in Orthodontic, run by National University of Malaysia at 3 sites in Malaysia.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 5 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: opening soon, as of the sponsor's last update on 22 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 3 sites in Malaysia. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Asma Ashari, BDS Adel, MClinDent Lon, MOrth (+603 8921 5555, asmaashari@ukm.edu.my), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Retention of the maxillary expansion (time frame: 12 months). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07659041, which also lists 10 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Jun 2026.

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