Comparison of Early Interceptive Orthodontic Appliances (Traditional and Novel) and Later Fixed Appliance Treatment in Class II Malocclusion.

NCT07404696 | Not Yet Recruiting

• 1 other identifier: RCT: Comparing Class II TX
• Study Type: interventional
• Target: 144
• Locations: 1 country
• Sites: 3

Brief Summary

Background Approximately 15% of children have a Class II malocclusion, where the maxilla is positioned anterior to the mandible, and around 90% of these children also present with an increased overjet. Increased overjet is associated with a higher risk of dental trauma and psychosocial consequences such as bullying and reduced oral health-related quality of life (OHRQoL). Functional orthodontic appliances (e.g., headgear-activator and Twin-block) have long been used to reduce overjet through dentoalveolar effects and by influencing mandibular position and growth. More recently, digital solutions such as Invisalign's mandibular advancement appliance have been introduced, with potential advantages including improved wear time and simultaneous tooth alignment. However, there is currently limited evidence regarding treatment outcomes, patient experience, and cost-effectiveness of these newer appliances compared with established functional appliances. Aim The primary aim is to compare treatment outcomes, patient experience, and cost-effectiveness of interceptive orthodontic treatment using three different appliances. The overall aim is to determine whether interceptive treatment of Class II malocclusion with large overjet is effective, and if so, which interceptive modality should be preferred. Study design and setting A total of 144 patients aged 9-13 years with Class II malocclusion and large overjet will be randomized into four groups:

• Headgear-activator
• Twin-block
• Aligner Mandibular advancement
• Control Participants will be treated at four Orthodontic Specialist Clinics within the National Health Service in Region Halland and Västra Götaland, Sweden. Treatments will be provided by two experienced orthodontic specialists. Follow-up and data collection Clinical examinations will be performed at:
• Baseline (T0)
• 9 months into treatment (T1)
• End of treatment (T2) Appliance checks will occur every 8 weeks. Digital scans of the occlusion will be collected at T0, T1, and T2. Lateral cephalometric radiographs will be taken at T0 and T2. Outcomes and planned analyses The trial will generate three studies with distinct outcomes:
• Treatment outcomes Primary outcome: dental treatment effectiveness measured as overjet reduction. Secondary outcomes: other dental variables, skeletal outcomes, and extraoral outcomes.
• Patient-reported outcomes
• Child Perception Questionnaire (CPQ): assesses the child's perception of their teeth before and after treatment.
• Orthodontic Treatment Impact Questionnaire (OTIQ): assesses the child's experience of orthodontic treatment and the appliance. These outcomes will be used to evaluate changes in OHRQoL from pre- to post-treatment and to compare experiences across treatment modalities.
• Cost-effectiveness analysis The economic evaluation will include direct, indirect, and societal costs. Treatment duration, number and length of appointments, and cancellations/no-shows will be recorded.
• Direct costs: premises, staff salaries, materials, and laboratory costs.
• Indirect costs: parental loss of income due to absence from work.
• Societal costs: direct + indirect costs. Costs will be related to treatment outcomes to estimate cost-effectiveness across the treatment arms. Additional comparison: early vs late treatment Furthermore, after completing 18 months the control group, and half of the functional appliance patients will receive treatment with fixed appliances. This enables an additional comparison of early interceptive treatment versus later treatment using the same outcomes: treatment effectiveness, patient-reported outcomes, and cost-effectiveness.

Conditions

Class II Malocclusion; Class II Malocclusion, Division 1; Overjet

Outcome Measures

Primary Outcomes (1)

• Part I: Dental treatment result: Overjet reduction

  Change in dental overjet compared to baseline. Unit: millimetres (mm). Direction of effect: Lower post-treatment overjet (i.e. greater reduction from baseline) indicates a better outcome; higher overjet values indicate a worse outcome.

  18 months

Secondary Outcomes (1)

• Part I: Dental treatment result: Sagittal relation, overbite

  18 months

Other Outcomes (7)

• Part I: Basal treatment result

  18 months

• Part I: Extra oral treatment result

  18 months

• Part II: Oral Health Related Quality of life (ORHQoL)

  18 months

Study Arms (4)

Head gear activator

EXPERIMENTAL

Treatment with head gear activator orthodontic appliance.

Device: Head gear activator

Twin Block

EXPERIMENTAL

Treatment with Twin Block appliance

Device: Twin Block

Invisalign Mandibular Advancement

EXPERIMENTAL

Treatment with Invisalign mandibular advancement featuring occlusal blocks.

Device: Invisalign mandibular advancement

Fixed appliance

EXPERIMENTAL

Participants will serve as an observation (no treatment) control group during the trial period for 18 months. After completion of the observation phase, they will receive orthodontic treatment with fixed appliances. Outcomes from this delayed intervention will be compared with the three early intervention groups.

Device: Fixed appliance

Interventions

Head gear activator DEVICE

Activator with extra orala head gear traction

Head gear activator

Twin Block DEVICE

Twin Block orthodontic appliance

Twin Block

Invisalign mandibular advancement DEVICE

Invisalign mandibular advancement featuring occlusal blocks

Invisalign Mandibular Advancement

Fixed appliance DEVICE

Fixed appliance in upper and lower jaw

Fixed appliance

Eligibility Criteria

• Age: 9 Years - 13 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17)

You may qualify if:

• Children age 9-13 years at the start of the trial
• Mixed dentition, DS3M1
• Excessive overjet ≥6 mm
• First permanent molars in at least half cusp Cl II relation bilaterally
• Incomplete lip closure

You may not qualify if:

• Treatment needing extractions due to severe crowding
• Earlier orthodontic treatment
• Mouth breathing
• Ongoing sucking habits
• Syndromic patients

Sponsors & Collaborators

• Vastra Gotaland Region: lead
• Region Halland: collaborator
• Göteborg University: collaborator
• Västra Götalandsregionen: collaborator

Study Sites (3)

Sahlgrenska Academy

Gothenburg, 40530, Sweden

Location

Orthodontic Specialist Clinic

Halmstad, 30246, Sweden

Location

Orthodontic Specialist Clinic

Kungsbacka, 43441, Sweden

Location

MeSH Terms

Conditions

Overbite; Malocclusion, Angle Class II

Interventions

Orthodontic Appliances, Fixed

Condition Hierarchy (Ancestors)

Malocclusion; Tooth Diseases; Stomatognathic Diseases

Intervention Hierarchy (Ancestors)

Orthodontic Appliances; Orthodontics; Dentistry

Study Officials

• Anna Westerlund, Professor

  Department of Orthodontics, Institution of Odontology, Sahlgrenska Academy, University of Gothenburg

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Sara Waldenström, PhD student

CONTACT

+46768522129; sara.waldenstrom@regionhalland.se

Anna Westerlund, Professor

CONTACT

+46317866877; anna.westerlund@odontologi.gu.se

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER GOV
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: Prospective randomized controlled, investigator-blinded, multicentre clinical trial.

Study Record Dates

• First Submitted: December 17, 2025
• First Posted: February 11, 2026
• Study Start: January 15, 2026
• Primary Completion (Estimated): March 1, 2031
• Study Completion (Estimated): March 1, 2031
• Last Updated: February 11, 2026

Record last verified: 2026-02

Locations

SE (3)