An interventional study of Upper-lower clear plastic retainers + Class III elastics and Upper-lower clear plastic retainers in Class III Malocclusion and Underbite, sponsored by Sydney Local Health District. Active, not recruiting at 2 sites in Australia. Open to participants aged 12 Years to 16 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-05-08.
Sponsored by Sydney Local Health District · Not applicable, Interventional, and Prevention
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.
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.
57 studies on the registry are indexed under Malocclusion, Angle Class III; 11 are open to participants now.
This study's planned enrollment of 42 is above the median of 32 across 53 interventional studies indexed under Malocclusion, Angle Class III.
Browse Malocclusion, Angle Class III studies →Sydney Local Health District is the lead sponsor of 5 studies on the registry; 2 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Upper-lower clear plastic retainers + Class III elastics
Other: Upper-lower clear plastic retainers + Class III elastics
Upper-lower clear plastic retainers
Other: Upper-lower clear plastic retainers
Addition of Class III elastics to clear plastic retainers
Upper-lower clear plastic retainers
Difference in overjet of participants in the 2 study arms
Measurement of overjet
Time frame: 5 years
Need for jaw surgery
Need for surgery assessed by a panel of orthodontists
Time frame: 5 years
Difference in upper jaw position
The difference in SNA angle measured on cephalometric radiographs between groups
Time frame: 5 years
Difference in lower jaw position
The difference in SNB angle measured on cephalometric radiographs between groups
Time frame: 5 years
Difference in upper-lower jaw relationship
The difference in ANB angle measured on cephalometric radiographs between groups
Time frame: 5 years
Difference in upper incisor angulation
The difference in upper incisor angle measured on cephalometric radiographs between groups
Time frame: 5 years
Difference in lower incisor angulation
The difference in lower incisor angle measured on cephalometric radiographs between groups
Time frame: 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
Time frame: 5 years
Effect of elastics on alignment retention
Little's irregularity index will be used to compare both groups
Time frame: 5 years
Periodontal health, including recession around the incisors
Presence of gingival recession and prominence of lower incisors will be evaluated for both groups
Time frame: 5 years
Plan to share: No
This study is active, not recruiting, as verified in May 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Malocclusion, Angle Class III →
Sydney Local Health District