The Effectiveness of the Twin Block and Carriere Motion Appliances in Post-pubertal Patients and an Evaluation of the Impact of Class II Malocclusion and Its Correction on Oral Health-related Quality of Life

Summary

The investigators of this clinical trial aim to:

* Compare the effectiveness and efficiency of Clark's Twin Block Appliance (CTB) vs Carriere Motion Appliance (CMA) in correcting Class II malocclusion when used in post-pubertal older adolescents, in terms of skeletal and dental change.
* Evaluate potential negative oral health-related quality of life (OHRQoL) impacts during the active treatment phase with either CTB or CMA in post-pubertal adolescents.
* Investigate the impact of Class II malocclusion on oral health-related quality of life (OHRQoL) in post-pubertal adolescents.

Class II division 1 malocclusion is a dental condition where the upper teeth protrude significantly over the lower teeth. It is a common type of malocclusion observed in orthodontic practice, accounting for approximately 20-25% globally. Correcting Class II malocclusion in growing patients using functional appliances and Class II correctors is relatively predictable.

In Ireland and the United Kingdom, the Clark's Twin Block (CTB) is the most commonly used functional appliance. The CTB consists of two components: one for the upper teeth and one for the lower teeth. These components are engineered to position the lower jaw forward, thereby promoting the desired dentoskeletal changes (moving the upper teeth back and lower forward). Another device used for Class II correction is the Carriere Motion Appliance (CMA). The CMA is gaining popularity as a treatment option for Class II malocclusion, inducing dental changes similar to those achieved with a CTB. However, uncertainty persists regarding the effectiveness of these appliances in older adolescents in the post-pubertal growth phase (aged approximately 14.5 years or above).

Additionally, although both CTB and CMA are effective in growing patients in correcting dental and skeletal discrepancies, they may influence daily activities, comfort, and psychological aspects, which often results in poor compliance. Poor adherence to orthodontic treatment, whether with fixed or removable appliances, can lead to higher rates of treatment failure.

Conditions

• CLASS II DIVISION 1 MALOCCLUSION
• Class II Malocclusion
• Growth
• Overjet
• Class II Buccal Segment Relationship
• Class II Growth Modification
• Distalization
• Oral Health-Related Quality of Life

Interventions

DEVICE

CTB

The appliance will be used with the bite registration taken in maximum protrusion incorporating the following features: (1) Adam's clasps on all first premolars and first permanent molars, (2) three ball-ended clasps on the mandibular incisors, (3) midline expansion screw in the maxillary component, (4) blocks intersecting at 70 degrees, with a height of 5-6 mm in the premolar region. Patients will be instructed to wear the appliance full-time, except for eating, and during contact or water sports. Objective wear time in minutes will be recorded by a Theramon® microsensor (Handelsagentur Gschladt, Hargelsberg, Austria, or Forestadent, Pforzheim, Germany) placed in the maxillary component.

DEVICE

CMA

The appliance consists of rigid stainless-steel or acrylic bars bonded to the maxillary canines and first molars bilaterally. Elastics will be worn in a Class II pattern, from hooks on the maxillary canine to attachments on the mandibular first molar (bonded molar tubes). Anchorage in the mandibular dentition will be provided by an Essix-type retainer. Patients will be instructed to wear elastics full time except for eating and cleaning the teeth. The elastics protocol for the CMA appliance will be: Force 1 elastics (Henry Schein Orthodontics) that generate about 375 g of force that will be used during the first 6 weeks, changed to Force 2 elastics that generate about 540 g of force thereafter.

Sponsors & Collaborators

• Health Service Executive, Ireland

  collaborator OTHER

• University of Dublin, Trinity College

  collaborator OTHER

• Dublin Dental University Hospital

  collaborator OTHER

• Aslam Alkadhimi

  lead OTHER

Principal Investigators

• Prof Padhraig Fleming · Chair/Professor of Orthodontics. Programme Lead, Doctorate in Orthodontics. Division of Public and Child Dental Health. Dublin Dental University Hospital.

• Aslam Alkadhimi · Dublin Dental Hospital, Trinity College Dublin

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

14 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-03-31

Primary Completion

2027-09-30

Completion

2029-09-30

Countries

• Ireland

Study Locations