Class III MalocclusionNCT04911400
Effects of Class III Elastics on Stability of Orthopaedic Class III Correction
A study testing Upper-lower clear plastic retainers + Class III elastics and Upper-lower clear plastic retainers in people with Class III Malocclusion and Underbite, run by Sydney Local Health District at 2 sites in Australia.
Trial summary
The purpose of this study is to evaluate the effects of adding elastics to orthodontic retainers on the stability of class III correction and whether it reduces the need for jaw surgery. Read more about this study
- Who is it for?
- Ages 12 to 16 yearsHealthy volunteers can take part
- Conditions the study is for
- Class III Malocclusion, Underbite
- What is being tested?
- Upper-lower clear plastic retainers + Class III elastics and Upper-lower clear plastic retainers
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 42 participants
- Where
- 2 sitesAustralia
- Study dates
- 22 Jul 2020to 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 12 to 16 years
- All sexes
- Healthy volunteers accepted
- Child
Who may be able to join
- Patients that completed their orthodontic treatment for the management of their skeletal class III with upper jaw retrusion that was treated with Class III orthopaedic appliances, followed by full fixed appliances.
- No congenital anomalies or craniofacial syndromes
- No other orthodontic treatment
- No medical history that effects growth
Who cannot join
- Congenital anomalies or craniofacial syndromes
- Other orthodontic treatment
- Medical history that effects growth
Trial locations and contacts
2 sites in 1 country.
Australia2 sites
Chatswood Orthodontics
Chatswood, New South Wales, 2067
Sydney Dental Hospital
Surry Hills, New South Wales, 2010
About this study
The purpose of this study is to evaluate the effects of adding elastics to orthodontic retainers on the stability of class III correction and whether it reduces the need for jaw surgery.
Read the detailed description
Over the years many types of appliances have been recommended for retaining Class III correction in growing children such as intermaxillary splints, class III activator, Frankel 3, Class III twin block, continued use of face-mask and chin-cup. However, currently none of these are in routine use and there is no evidence on the long term effectiveness of any retention protocol for class III correction.
One of the most commonly used retainers following orthodontic treatment is clear plastic retainers. There are no studies that investigated whether using class III elastics in combination with clear plastic retainers improves the stability of class III correction and reduces the need for later jaw surgery.
- Conditions
- Class III Malocclusion, Underbite
- Being tested
- Upper-lower clear plastic retainers + Class III elastics, Upper-lower clear plastic retainers
- Keywords
- Class III Malocclusion, Orthodontic retention
- Medical subject headings
- Malocclusion, Angle Class III
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Upper-lower clear plastic retainers + Class III elasticsOther
Addition of Class III elastics to clear plastic retainers
Upper-lower clear plastic retainersOther
Upper-lower clear plastic retainers
| Study group | Role | What they receive |
|---|---|---|
| Upper-lower clear plastic retainers + Class III elastics | Experimental | Upper-lower clear plastic retainers + Class III elastics Receives: Other: Upper-lower clear plastic retainers + Class III elastics |
| Upper-lower clear plastic retainers | Active comparator | Upper-lower clear plastic retainers Receives: Other: Upper-lower clear plastic retainers |
What is being measured
The primary outcome is the main question the study is designed to answer.
Difference in overjet of participants in the 2 study arms
Measurement of overjet
Measured: 5 years
Secondary outcomes (9)
Need for jaw surgery
Need for surgery assessed by a panel of orthodontists
Measured: 5 years
Difference in upper jaw position
The difference in SNA angle measured on cephalometric radiographs between groups
Measured: 5 years
Difference in lower jaw position
The difference in SNB angle measured on cephalometric radiographs between groups
Measured: 5 years
Difference in upper-lower jaw relationship
The difference in ANB angle measured on cephalometric radiographs between groups
Measured: 5 years
Difference in upper incisor angulation
The difference in upper incisor angle measured on cephalometric radiographs between groups
Measured: 5 years
Difference in lower incisor angulation
The difference in lower incisor angle measured on cephalometric radiographs between groups
Measured: 5 years
Compliance and ease of use of both retention regimens
Questionnaire on the frequency and ease of use of both retainer regimens will be used
Measured: 5 years
Effect of elastics on alignment retention
Little's irregularity index will be used to compare both groups
Measured: 5 years
Periodontal health, including recession around the incisors
Presence of gingival recession and prominence of lower incisors will be evaluated for both groups
Measured: 5 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Jun 2021
- Study start22 Jul 2020
- Primary completionJan 2027 (estimated)
- Study completionDec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Class III MalocclusionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 42 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Sydney Local Health District
- Sponsor type
- Other government
- Responsible party
- Sponsor
- Investigators
- Oyku Dalci, DDS, PhD, Principal investigator, Sydney Local Health District, The University of Sydney
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04911400
- Sponsor's protocol ID
- X19-0365
- Status last verified
- May 2026
- First submitted
- 9 May 2021
- Last updated
- 8 May 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Owens D, Watkinson S, Harrison JE, Turner S, Worthington HV. Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children. Cochrane Database Syst Rev. 2024 Apr 10;4(4):CD003451. doi: 10.1002/14651858.CD003451.pub3.
PubMed 38597341
Study at a glance
From the registry record, last updated by the sponsor on 8 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Class III Elastics on Stability of Orthopaedic Class III Correction
- ClinicalTrials.gov ID
- NCT04911400
- Acronym / sponsor ID
- X19-0365
- Conditions
- Class III Malocclusion, Underbite
- Keywords
- Class III Malocclusion, Orthodontic retention
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 42 participants (estimated)
- Lead sponsor
- Sydney Local Health DistrictOther government
- Study start
- 22 Jul 2020 (actual)
- Primary completion
- Jan 2027 (estimated)
- Study completion
- Dec 2027 (estimated)
- First posted
- 3 Jun 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to evaluate the effects of adding elastics to orthodontic retainers on the stability of class III correction and whether it reduces the need for jaw surgery.
Detailed description
Over the years many types of appliances have been recommended for retaining Class III correction in growing children such as intermaxillary splints, class III activator, Frankel 3, Class III twin block, continued use of face-mask and chin-cup. However, currently none of these are in routine use and there is no evidence on the long term effectiveness of any retention protocol for class III correction.
One of the most commonly used retainers following orthodontic treatment is clear plastic retainers. There are no studies that investigated whether using class III elastics in combination with clear plastic retainers improves the stability of class III correction and reduces the need for later jaw surgery.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Upper-lower clear plastic retainers + Class III elastics | Experimental | Other: Upper-lower clear plastic retainers + Class III elasticsUpper-lower clear plastic retainers + Class III elastics |
| Upper-lower clear plastic retainers | Active comparator | Other: Upper-lower clear plastic retainersUpper-lower clear plastic retainers |
Who may qualify
- Ages
- 12 to 16 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
Key inclusion criteria (4 listed)
- Patients that completed their orthodontic treatment for the management of their skeletal class III with upper jaw retrusion that was treated with Class III orthopaedic appliances, followed by full fixed appliances.
- No congenital anomalies or craniofacial syndromes
- No other orthodontic treatment
- No medical history that effects growth
Key exclusion criteria (3 listed)
- Congenital anomalies or craniofacial syndromes
- Other orthodontic treatment
- Medical history that effects growth
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Upper-lower clear plastic retainers + Class III elasticsAddition of Class III elastics to clear plastic retainers | Other | Upper-lower clear plastic retainers + Class III elastics |
| Upper-lower clear plastic retainersUpper-lower clear plastic retainers | Other | Upper-lower clear plastic retainers |
Primary outcome
Difference in overjet of participants in the 2 study arms
Time frame: 5 years
Measurement of overjet
9 secondary outcomes
Need for jaw surgery
Time frame: 5 years
Difference in upper jaw position
Time frame: 5 years
Difference in lower jaw position
Time frame: 5 years
Difference in upper-lower jaw relationship
Time frame: 5 years
Difference in upper incisor angulation
Time frame: 5 years
Difference in lower incisor angulation
Time frame: 5 years
Compliance and ease of use of both retention regimens
Time frame: 5 years
Effect of elastics on alignment retention
Time frame: 5 years
Periodontal health, including recession around the incisors
Time frame: 5 years
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 May 2026.
- Derived from this study: PubMed 38597341Owens D, Watkinson S, Harrison JE, Turner S, Worthington HV. Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children. Cochrane Database Syst Rev. 2024 Apr 10;4(4):CD003451. doi: 10.1002/14651858.CD003451.pub3.
- Individual participant dataSharing planned: No
Related trials for Class III Malocclusion
RecruitingObservational study
Natural History of Craniofacial Anomalies and Developmental Growth Variants
Prognathism, Retrognathism
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Treatment of Mandibular Overjet in Children With Maxillary Retrognathism
Maxillary Retrognathism, Children
Recruiting
Comparing 3D-Printed and Milled Titanium Plates in Jaw Surgery (Le Fort I): Accuracy and Operative Time
Malocclusion, Angle Class II, Malocclusion, Angle Class III
Not yet recruiting
3D Printed Occlusal Splints for Intraoperative Use
Malocclusion, Angle Class I, Malocclusion, Angle Class II
Not yet recruiting
Clinical and Radiographic Evaluation of Low Sagittal Medial Ramus Osteotomy for Treatment of Skeletal Class II and Class III Malocclusion
Skeletal Class II Malocclusion, Skeletal Class III Malocclusion
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Oyku Dalci, DDS, PhD principal investigator
Sydney Local Health District, The University of Sydney
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Upper-lower clear plastic retainers + Class III elastics and Upper-lower clear plastic retainers in people with Class III Malocclusion and Underbite, run by Sydney Local Health District at 2 sites in Australia.
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 4 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: under way, not looking for participants, as of the sponsor's last update on 8 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Australia. 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?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Difference in overjet of participants in the 2 study arms (time frame: 5 years). 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 NCT04911400, which also lists 1 linked publication.
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 8 May 2026.