Class II MalocclusionNCT05597748
Modified Herbst Approach to Improve Chin Projection
A study testing Modified Herbst Approach and Conventional Herbst Approach in people with Class II Malocclusion, run by University of Alberta at 1 site in Canada.
Trial 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. Read more about this study
- Who is it for?
- Ages 12 to 15 yearsHealthy volunteers can take part
- Conditions the study is for
- Class II Malocclusion
- What is being tested?
- Modified Herbst Approach and Conventional Herbst Approach
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 0 participants
- Where
- 1 siteCanada
- Study dates
- 25 Aug 2023to 31 Jul 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 to 15 years
- All sexes
- Healthy volunteers accepted
- Child
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Modified Herbst Approach to Improve Chin Projection in Class II Malocclusion Patients: A Randomized Controlled Trial
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.
Read the detailed description
Purpose
The present study will compare facial, skeletal, and dental changes among adolescents with mild to moderate Class II malocclusion using two Class II orthopedic orthodontic approaches. Patient-reported outcomes will also be assessed through validated questionnaires and qualitative interviews.
Hypothesis
Participants that use the modified Herbst approach do not showcase facial, dental, and skeletal changes that are different than those using the conventional Herbst approach.
Justification
One of the most common causes of a Class II malocclusion is a deficient mandibular projection (either due to reduced size or retruded position). Although in adults the only reasonable way to improve the mandibular projection is through surgical repositioning, in growing individuals an orthopedic alternative may significantly reduce the perceived need for this type of surgery later in life.
Several craniofacial orthopedic appliances have been used to attempt an orthopedic correction of Class II malocclusion of a mandibular origin, aiming to possibly improve functional, muscular, skeletal, and dental disharmonies.1,2,3 A wide array of related publications exist that have been summarized through several systematic reviews with or without meta-analysis.
The Herbst appliance is widely known for its relative effectiveness in correcting Class II malocclusions. It is most commonly used as a fixed appliance that repositions the jaw to a more anterior and downward position displacing the condyles away from the articular eminence.4,-8 This is thought to facilitate condylar bone apposition; hence, increasing mandibular size dimensions. Several papers have considered the efficiency of the Herbst appliance in Class II correction during early permanent dentition. But only one study evaluated changes produced by the Herbst appliance in mixed dentition patients and it concluded that the effects of the Herbst appliance were mainly dentoalveolar.5 Several different designs of the Herbst appliance have been reported in the literature.6-11
A modified Herbst approach by Manni has shown promising results. An increment in the mandibular chin projection of 5 mm has been reported. Due to the fact that the reported positive changes are so far only based on case reports and retrospective data12-24, a randomized controlled trial seems to be the next prudent step.
Objectives
Assess if the modified Herbst approach produces facial, dental, and skeletal changes that are different than those using the conventional Herbst approach.
Assess if the use of the modified Herbst approach facilitates a treatment experience (overall quality of life, oral health-related quality of life, and described experience) that is different than the one with the conventional Herbst approach.
Methods
Each potential participant will undergo an orthodontic clinical screening to determine if they fill the inclusion criteria (mild to moderate Class II malocclusion in a growing individual - two distinct Class II malocclusion phenotypes - see eligibility criteria below). Eligible individuals will be approached with an opportunity to participate in the research study. After understanding the research purpose and possible side effects, and if they choose to participate, they will voluntarily sign the informed consent form.
They will be randomly assigned to one of two groups. The allocation sequence will be done through randomization tables by a statistician and sealed envelopes generated. Once a willing participant is deemed to have fulfilled the inclusion criteria and provided informed consent the randomization will occur. For each Class II malocclusion type, two groups will be randomly generated.
Group 1 - Class II type A malocclusion - proclination of upper incisors indicated. 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. For Type, A upper brackets will be initially bonded and upper incisors proclined until normal inclination values are attained.
Group 2 - Class II type B malocclusion - proclination of upper incisors not indicated. 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. For Type, A initially upper brackets will be initially bonded and upper incisors proclined until normal inclination values are attained.
Both treatment arms will start as soon as the randomization has been done. Full orthodontic records (2D x-rays, photos, and dental casts) will be obtained for both groups at baseline and after this treatment phase is completed. Further comprehensive treatment will be offered to these patients as this initial management approach is not expected to fully align and level the teeth. This would be an additional elective option at an additional cost.
Two validated quality-of-life tools will be used. The CPQ11-14 assesses oral health-related quality of life and the EuroQoL assesses the overall quality of life. These two tools will be collected before and after this management approach. Additionally, a qualitative approach will be used at the end of the trial participants to better understand the participant's journey through the process.
Sample size
A sample of 40 patients (8 patients per treatment group are needed but the total sample is set to 10 considering a 20% loss during follow-up) will be sought. This sample was based on alfa of 5% and a beta of 20%. A clinically significant difference of 4.9 mm in Pg to OLp and a variance of 12.25 was set as clinically meaningful based on the pilot retrospective study by Manni et al.16.
n=f(a,b)*2SD2/Dif2 25
f(a,b)=7.85 (Table XIII page 22) 25
sd=12.25 Manni et al.16
Expected difference= 4.9 mm Pg to OLp Manni et al.16
- Conditions
- Class II Malocclusion
- Being tested
- Modified Herbst Approach, Conventional Herbst Approach
- Medical subject headings
- Overbite
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Modified Herbst ApproachDevice
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.
Conventional Herbst ApproachDevice
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.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: 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. Receives: 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. Receives: Device: Modified Herbst Approach |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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
Measured: 1 year
Secondary outcomes (3)
Maxillary lip prominence
Assess if the modified Herbst approach produces a less prominent lip protrusion. The distance in mm between the upper lip and a perpendicular virtual reference line will be calculated.
Measured: 1 year
Mandibular lip prominence
Assess if the modified Herbst approach produces a more prominent lip protrusion. The distance in mm between the lower lip and a perpendicular virtual reference line will be calculated.
Measured: 1 year
Upper incisor inclination
Assess if the modified Herbst approach produces less incisor inclination than the conventional Herbst approach. The angulation in degrees between the upper incisor and the maxillary plane will be calculated.
Measured: 1 year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Oct 2022
- Study start25 Aug 2023
- Primary completion31 Jul 2025
- Study completion31 Jul 2025
Why it stopped: Recruitment difficulties
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Class II MalocclusionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Four parallel arms all under treatment
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 0 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Alberta
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Carlos Flores Mir, DSc, Principal investigator, University of Alberta
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05597748
- Sponsor's protocol ID
- Pro00124682
- Status last verified
- Jul 2025
- First submitted
- 11 Oct 2022
- Last updated
- 6 Aug 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Only the participant's unique ID is stored as personal identifying information. To be able to link this ID to specific participant identifiable information access to our password-protected health database would be needed.
Study at a glance
From the registry record, last updated by the sponsor on 6 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Modified Herbst Approach to Improve Chin Projection in Class II Malocclusion Patients: A Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT05597748
- Acronym / sponsor ID
- Pro00124682
- Conditions
- Class II Malocclusion
- Study type
- Interventional
- Recruitment status
- WithdrawnReason stopped: Recruitment difficulties
- Enrolment
- 0 participants (actual)
- Lead sponsor
- University of AlbertaUniversity, hospital or other
- Study start
- 25 Aug 2023 (actual)
- Primary completion
- 31 Jul 2025 (actual)
- Study completion
- 31 Jul 2025 (actual)
- First posted
- 28 Oct 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
Purpose
The present study will compare facial, skeletal, and dental changes among adolescents with mild to moderate Class II malocclusion using two Class II orthopedic orthodontic approaches. Patient-reported outcomes will also be assessed through validated questionnaires and qualitative interviews.
Hypothesis
Participants that use the modified Herbst approach do not showcase facial, dental, and skeletal changes that are different than those using the conventional Herbst approach.
Justification
One of the most common causes of a Class II malocclusion is a deficient mandibular projection (either due to reduced size or retruded position). Although in adults the only reasonable way to improve the mandibular projection is through surgical repositioning, in growing individuals an orthopedic alternative may significantly reduce the perceived need for this type of surgery later in life.
Several craniofacial orthopedic appliances have been used to attempt an orthopedic correction of Class II malocclusion of a mandibular origin, aiming to possibly improve functional, muscular, skeletal, and dental disharmonies.1,2,3 A wide array of related publications exist that have been summarized through several systematic reviews with or without meta-analysis.
The Herbst appliance is widely known for its relative effectiveness in correcting Class II malocclusions. It is most commonly used as a fixed appliance that repositions the jaw to a more anterior and downward position displacing the condyles away from the articular eminence.4,-8 This is thought to facilitate condylar bone apposition; hence, increasing mandibular size dimensions. Several papers have considered the efficiency of the Herbst appliance in Class II correction during early permanent dentition. But only one study evaluated changes produced by the Herbst appliance in mixed dentition patients and it concluded that the effects of the Herbst appliance were mainly dentoalveolar.5 Several different designs of the Herbst appliance have been reported in the literature.6-11
A modified Herbst approach by Manni has shown promising results. An increment in the mandibular chin projection of 5 mm has been reported. Due to the fact that the reported positive changes are so far only based on case reports and retrospective data12-24, a randomized controlled trial seems to be the next prudent step.
Objectives
Assess if the modified Herbst approach produces facial, dental, and skeletal changes that are different than those using the conventional Herbst approach.
Assess if the use of the modified Herbst approach facilitates a treatment experience (overall quality of life, oral health-related quality of life, and described experience) that is different than the one with the conventional Herbst approach.
Methods
Each potential participant will undergo an orthodontic clinical screening to determine if they fill the inclusion criteria (mild to moderate Class II malocclusion in a growing individual - two distinct Class II malocclusion phenotypes - see eligibility criteria below). Eligible individuals will be approached with an opportunity to participate in the research study. After understanding the research purpose and possible side effects, and if they choose to participate, they will voluntarily sign the informed consent form.
They will be randomly assigned to one of two groups. The allocation sequence will be done through randomization tables by a statistician and sealed envelopes generated. Once a willing participant is deemed to have fulfilled the inclusion criteria and provided informed consent the randomization will occur. For each Class II malocclusion type, two groups will be randomly generated.
Group 1 - Class II type A malocclusion - proclination of upper incisors indicated. 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. For Type, A upper brackets will be initially bonded and upper incisors proclined until normal inclination values are attained.
Group 2 - Class II type B malocclusion - proclination of upper incisors not indicated. 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. For Type, A initially upper brackets will be initially bonded and upper incisors proclined until normal inclination values are attained.
Both treatment arms will start as soon as the randomization has been done. Full orthodontic records (2D x-rays, photos, and dental casts) will be obtained for both groups at baseline and after this treatment phase is completed. Further comprehensive treatment will be offered to these patients as this initial management approach is not expected to fully align and level the teeth. This would be an additional elective option at an additional cost.
Two validated quality-of-life tools will be used. The CPQ11-14 assesses oral health-related quality of life and the EuroQoL assesses the overall quality of life. These two tools will be collected before and after this management approach. Additionally, a qualitative approach will be used at the end of the trial participants to better understand the participant's journey through the process.
Sample size
A sample of 40 patients (8 patients per treatment group are needed but the total sample is set to 10 considering a 20% loss during follow-up) will be sought. This sample was based on alfa of 5% and a beta of 20%. A clinically significant difference of 4.9 mm in Pg to OLp and a variance of 12.25 was set as clinically meaningful based on the pilot retrospective study by Manni et al.16.
n=f(a,b)*2SD2/Dif2 25
f(a,b)=7.85 (Table XIII page 22) 25
sd=12.25 Manni et al.16
Expected difference= 4.9 mm Pg to OLp Manni et al.16
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 4
- Model description
- Four parallel arms all under treatment
| Arm | Type | Receives |
|---|---|---|
| Class II type A malocclusion - proclination of upper incisors indicated - No TADs | Active comparator | Device: Conventional Herbst ApproachA 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. |
| Class II type B malocclusion - proclination of upper incisors not indicated - No TADs | Active comparator | Device: Conventional Herbst ApproachA 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 - TADs | Experimental | Device: Modified Herbst ApproachA 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 B malocclusion - proclination of upper incisors not indicated - TADs | Experimental | Device: Modified Herbst ApproachCA 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. |
Who may qualify
- Ages
- 12 to 15 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
Key inclusion criteria (5 listed)
- 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.
Key exclusion criteria (5 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Modified Herbst ApproachA 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 | 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 ApproachA 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 | 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 |
Primary outcome
Skeletal chin prominence
Time frame: 1 year
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.
Lower incisor inclination
Time frame: 1 year
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.
Overall quality of life
Time frame: 1 year
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.
Oral health-related quality of life
Time frame: 1 year
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.
Soft tissue Chin prominence
Time frame: 1 year
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
3 secondary outcomes
Maxillary lip prominence
Time frame: 1 year
Mandibular lip prominence
Time frame: 1 year
Upper incisor inclination
Time frame: 1 year
Results and safety
The study was withdrawn before enrolling participants, so there are no results.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Aug 2025.
- Individual participant dataSharing planned: No. Only the participant's unique ID is stored as personal identifying information. To be able to link this ID to specific participant identifiable information access to our password-protected health database would be needed.
Related trials for Class II Malocclusion
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Malocclusion, Angle Class II, Malocclusion, Angle Class III
Recruiting
Treatment of Mild Class II Malocclusion in Adult Patients With Clear Aligners Versus Fixed Multibracket Therapy
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Recruiting
Treatment of Skeletal Class II Malocclusion With Modified Twin-Block Appliance With Clear Plates
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Recruiting
Patient-Reported Outcomes for Different Orthodontic Thermoplastics Used in Clear Aligners
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Carlos Flores Mir, DSc principal investigator
University of Alberta
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Modified Herbst Approach and Conventional Herbst Approach in people with Class II Malocclusion, run by University of Alberta at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: withdrawn, as of the sponsor's last update on 6 Aug 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study was withdrawn before enrolling participants, so there are no results.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Skeletal chin prominence (time frame: 1 year). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Aug 2025.