Modified Herbst Approach to Improve Chin Projection

NCT05597748 | Withdrawn

• 1 other identifier: Pro00124682
• Study Type: interventional
• Target: N/A
• Locations: 1 country
• Sites: 1

Brief Summary

This study will collect data to try to assess which one of the two management options works better. The first option involves the use of the bite corrector first and then braces, while the second option involves the temporary addition of small support bone screws with the bite corrector later and then braces. Currently, it is not clearly known if there are important differences between the proposed management options. Such approaches are conventionally used in orthodontic practices. The information collected in this study will be used to compare the differences in the nature of the facial, teeth, and bone changes after the treatment. Questions about the experience while using the devices will be asked.

Conditions

Class II Malocclusion

Outcome Measures

Primary Outcomes (5)

• Skeletal chin prominence

  Assess if the modified Herbst approach produces a more prominent chin protrusion than the one produced by the conventional Herbst. The distance in mm between the skeletal chin and a perpendicular virtual reference line will be calculated.

  1 year

• Lower incisor inclination

  Assess if the modified Herbst approach produces less incisor inclination than the conventional Herbst approach. The angulation in degrees between the lower incisor and the mandibular plane will be calculated.

  1 year

• Overall quality of life

  Assess if the overall quality of life is different than the one with the conventional Herbst approach. The CPQ11-14 ISF questionnaire will be used to assess oral health-related quality of life. The range of possible values es between 0 and 32. Lower values implied better perceived QoL.

  1 year

• Oral health-related quality of life

  Assess if the oral health-related quality of life is different than the one with the conventional Herbst approach. The EuroQoL questionnaire will be used to assess oral health-related quality of life. The index calculates a value between 0 and 1. A higher value implies better QoL.

  1 year

• Soft tissue Chin prominence

  Assess if the modified Herbst approach produces a more prominent chin protrusion. The distance in mm between the lower lip and a perpendicular virtual reference line will be calculated

  1 year

Secondary Outcomes (3)

• Maxillary lip prominence

  1 year

• Mandibular lip prominence

  1 year

• Upper incisor inclination

  1 year

Study Arms (4)

Class II type A malocclusion - proclination of upper incisors indicated - No TADs

ACTIVE COMPARATOR

A hybrid Herbst appliance approach will be used (current available conventional treatment). The upper jaw component will be a maxillary expander secured on the first molar bands. The lower arch would have an uncemented lower acrylic full-coverage splint-type. In between Herbst-type pistons will be used. Upper brackets will be initially bonded and upper incisors proclined until normal inclination values are attained.

Device: Conventional Herbst Approach

Class II type B malocclusion - proclination of upper incisors not indicated - No TADs

ACTIVE COMPARATOR

A hybrid Herbst appliance approach will be used (current available conventional treatment). The upper jaw component will be a maxillary expander secured on the first molar bands. The lower arch would have an uncemented lower acrylic full-coverage splint-type. In between Herbst-type pistons will be used.

Device: Conventional Herbst Approach

Class II type A malocclusion - proclination of upper incisors indicated - TADs

EXPERIMENTAL

A modified hybrid Herbst appliance approach (same hybrid Herbst appliance approach but with the addition of temporary anchorage devices (TADs) in both arches) will be used (alternative treatment). In the upper arch, the TADs would be inserted in the paramedical palatal area. In the lower arch, they would be inserted buccally between the roots of the lower second premolar and the first permanent molar. Elastomeric chains will be used to link these TADs to the first molars in the upper arch and to a buccal bottom on the lower canines. Upper brackets will be initially bonded and upper incisors proclined until normal inclination values are attained.

Device: Modified Herbst Approach

Class II type B malocclusion - proclination of upper incisors not indicated - TADs

EXPERIMENTAL

CA modified hybrid Herbst appliance approach (same hybrid Herbst appliance approach but with the addition of temporary anchorage devices (TADs) in both arches) will be used (alternative treatment). In the upper arch, the TADs would be inserted in the paramedical palatal area. In the lower arch, they would be inserted buccally between the roots of the lower second premolar and the first permanent molar. Elastomeric chains will be used to link these TADs to the first molars in the upper arch and to a buccal bottom on the lower canines.

Device: Modified Herbst Approach

Interventions

Modified Herbst Approach DEVICE

A modified hybrid Herbst appliance approach (same hybrid Herbst appliance approach but with the addition of temporary anchorage devices (TADs) in both arches) will be used (alternative treatment). In the upper arch, the TADs would be inserted in the paramedical palatal area. In the lower arch, they would be inserted buccally between the roots of the lower second premolar and the first permanent molar. Elastomeric chains will be used to link these TADs to the first molars in the upper arch and to a buccal bottom on the lower canines. Upper brackets will be initially bonded and upper incisors proclined until normal inclination values are attained.

Class II type A malocclusion - proclination of upper incisors indicated - TADs; Class II type B malocclusion - proclination of upper incisors not indicated - TADs

Conventional Herbst Approach DEVICE

A hybrid Herbst appliance approach will be used (current available conventional treatment). The upper jaw component will be a maxillary expander secured on the first molar bands. The lower arch would have an uncemented lower acrylic full-coverage splint-type. In between Herbst-type pistons will be used.

Class II type A malocclusion - proclination of upper incisors indicated - No TADs; Class II type B malocclusion - proclination of upper incisors not indicated - No TADs

Eligibility Criteria

• Age: 12 Years - 15 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• Class II skeletal malocclusion based on PgOLp more than 85 mm and A-OLp more than 75 mm.
• Perceived potential improvement of facial convexity.
• At least end-to-end bilateral molar relationship.
• Early permanent dentition.
• No congenitally missing teeth.

You may not qualify if:

• Class II skeletal malocclusion based on PgOLp less than 85 mm and A-OLp less than 75 mm.
• Only reasonable management option is surgery.
• Less than an end-to-end bilateral molar relationship.
• Mixed dentition dentition.
• Congenitally missing teeth.

Sponsors & Collaborators

• University of Alberta: lead

Study Sites (1)

University of Alberta

Edmonton, Alberta, T6G 2C8, Canada

Location

MeSH Terms

Conditions

Overbite

Condition Hierarchy (Ancestors)

Malocclusion, Angle Class II; Malocclusion; Tooth Diseases; Stomatognathic Diseases

Study Officials

• Carlos Flores Mir, DSc

  University of Alberta

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: The patient and care provider can't be masked as it is obvious what appliance modification is being used.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Four parallel arms all under treatment

Study Record Dates

• First Submitted: October 11, 2022
• First Posted: October 28, 2022
• Study Start: August 25, 2023
• Primary Completion: July 31, 2025
• Study Completion: July 31, 2025
• Last Updated: August 6, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)