Effects of Class III Elastics on Stability of Orthopaedic Class III Correction

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.

Study Overview

• Status: Active, not recruiting
• Conditions: Class III Malocclusion; Underbite
• Intervention / Treatment: Other: Upper-lower clear plastic retainers + Class III elastics; Other: Upper-lower clear plastic retainers

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 Type: Interventional
• Enrollment (Estimated): 42
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Australia
  • New South Wales
    • Chatswood, New South Wales, Australia, 2067
      • Chatswood Orthodontics
    • Surry Hills, New South Wales, Australia, 2010
      • Sydney Dental Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 12 years to 16 years (Child)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• 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

Exclusion Criteria:

• Congenital anomalies or craniofacial syndromes
• Other orthodontic treatment
• Medical history that effects growth

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Upper-lower clear plastic retainers + Class III elastics	Other: Upper-lower clear plastic retainers + Class III elastics; Addition of Class III elastics to clear plastic retainers
Active Comparator: Upper-lower clear plastic retainers	Other: Upper-lower clear plastic retainers; Upper-lower clear plastic retainers

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in overjet of participants in the 2 study arms	Measurement of overjet	5 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Need for jaw surgery	Need for surgery assessed by a panel of orthodontists	5 years
Difference in upper jaw position	The difference in SNA angle measured on cephalometric radiographs between groups	5 years
Difference in lower jaw position	The difference in SNB angle measured on cephalometric radiographs between groups	5 years
Difference in upper-lower jaw relationship	The difference in ANB angle measured on cephalometric radiographs between groups	5 years
Difference in upper incisor angulation	The difference in upper incisor angle measured on cephalometric radiographs between groups	5 years
Difference in lower incisor angulation	The difference in lower incisor angle measured on cephalometric radiographs between groups	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	5 years
Effect of elastics on alignment retention	Little's irregularity index will be used to compare both groups	5 years
Periodontal health, including recession around the incisors	Presence of gingival recession and prominence of lower incisors will be evaluated for both groups	5 years

Collaborators and Investigators

• Sponsor: Sydney Local Health District
• Investigators: Principal Investigator: Oyku Dalci, DDS, PhD, Sydney Local Health District, The University of Sydney

Publications and helpful links

General 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.

Study record dates

Study Major Dates

• Study Start (Actual): July 22, 2020
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: May 9, 2021
• First Submitted That Met QC Criteria: May 27, 2021
• First Posted (Actual): June 3, 2021

Study Record Updates

• Last Update Posted (Actual): May 8, 2026
• Last Update Submitted That Met QC Criteria: May 7, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Orthodontic retention; Class III Malocclusion
• Additional Relevant MeSH Terms: Stomatognathic Diseases; Tooth Diseases; Malocclusion; Malocclusion, Angle Class III
• Other Study ID Numbers: X19-0365

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No