Patients With Anterior Open Bite Malocclusion and Who Benefited of an Orthognathic SurgeryCOBA 50NCT07520682
Orthognathic Surgery in Anterior Open Bite: a Retrospective Study of 50 Patients With Initial Tongue Malposition
An observational study of Patients With Anterior Open Bite Malocclusion and Who Benefited of an Orthognathic Surgery and Infantile Swallowing and Tongue Malposition Necessitating Tongue Rehabilitation, run by Hospices Civils de Lyon at 1 site in France.
Trial summary
The anterior gap is defined by a lack of contact between the upper and lower dental arches. It is mainly due to the persistence of infantile swallowing during and after childhood, i.e. interposition of the tongue between the two dental arches. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Patients With Anterior Open Bite Malocclusion and Who Benefited of an Orthognathic Surgery, Infantile Swallowing and Tongue Malposition Necessitating Tongue Rehabilitation
- What is being tested?
- type of post-operative rehabilitation : with physiotherapy or speech therapy
- How many people
- 50 participants
- Where
- 1 siteFrance
- Study dates
- 1 Jan 2022to 1 Aug 2025
- Phase
- Observational
- 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 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: patients undergoing orthognathic surgery with a gap prior to surgery (50 patients)
Who may be able to join
- Major patients
- Having undergone ortho gnathic surgery in the Maxillofacial Surgery Department of the Croix Rousse Hospital
- Patients with an anterior gap of more than 3 mm
- Abnormal tongue position at diagnosis
Who cannot join
- Syndromic patients (cleft lip and palate, craniostenosis)
- Patient refusal
Trial locations and contacts
1 site in 1 country.
France1 site
Service de chirurgie en maxillo-faciale Hôpital de la Croix Rousse -Lyon
Lyon, France, 69004
About this study
The anterior gap is defined by a lack of contact between the upper and lower dental arches.
It is mainly due to the persistence of infantile swallowing during and after childhood, i.e. interposition of the tongue between the two dental arches.
Read more
Patients presenting with an anterior gap in adulthood are likely to develop functional sequelae (masticatory difficulties, dental loosening, periodontal disease, etc.) and aesthetic sequelae (edentulous smile, excess height of the lower third of the face compared to the upper and middle third).
Patients who are diagnosed with this condition very often benefit from orthodontic-surgical treatment, comprising a period of orthodontics followed by orthognathic surgery to close the anterior gap. This is combined with lingual re-education to treat infantile swallowing. This lingual re-education is not always carried out, either because infantile swallowing has not been diagnosed, or because of a lack of cooperation on the part of the patient, or because of difficulties in finding a suitable specialist. When rehabilitation is introduced, it is sometimes only after surgery, and for a short time.
For example, it has been observed that among all patients undergoing orthognathic surgery, those with an anterior gap were particularly at risk of surgical treatment failure, or recurrence in the short to medium term.
The main reason cited was the persistence of infantile swallowing and consequent malpositioning of the tongue between the dental arches, creating permanent pressure on the lingual surface of the teeth and eventually leading to recurrence of the gap.
Identifying patient management factors associated with postoperative recurrence of anterior hollowness in patients with infantile swallowing would enable us to adapt the management of these patients.
- Conditions
- Patients With Anterior Open Bite Malocclusion and Who Benefited of an Orthognathic Surgery, Infantile Swallowing and Tongue Malposition Necessitating Tongue Rehabilitation
- Being tested
- type of post-operative rehabilitation : with physiotherapy or speech therapy
- Keywords
- Anterior open bite, Orthognathic surgery, Tongue rehabilitation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
type of post-operative rehabilitation : with physiotherapy or speech therapyOther
mean duration of rehabilitation
- assess the tongue position at rest, and during speech
- assess the surgical movements associated with relapse : advancement, rotation, expansion, genioplasty
| Study group | Role | What they receive |
|---|---|---|
| Relapse of anterior open bite | All patients who presented relapse of anterior open bite after 6 months post operative. Receives: Other: type of post-operative rehabilitation : with physiotherapy or speech therapy | |
| No relapse of anterior open bite | All patients who did not present a relapse of anterior open bite after 6 months post operative. Receives: Other: type of post-operative rehabilitation : with physiotherapy or speech therapy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Measurement of the association between anterior open bite recurrence, defined as the absence of contact between the upper and lower incisors at 6 months postoperatively, and the rehabilitation factors.
Duration of rehabilitation in months
Measured: 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Apr 2026
- Study start1 Jan 2022
- Primary completion1 Jan 2025
- Study completion1 Aug 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Patients With Anterior Open Bite Malocclusion and Who Benefited of an Orthognathic SurgeryStudies of the same condition, open and under way.
- More trials run by Hospices Civils de LyonThe sponsor's other registered studies.
- 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
- Observational
- Observational model
- Cohort
- Time perspective
- Retrospective
- Enrolment
- 50 participants (actual)
Sponsor and investigators
- Lead sponsor
- Hospices Civils de Lyon
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07520682
- Sponsor's protocol ID
- 25-5191
- Acronym
- COBA 50
- Status last verified
- Apr 2026
- First submitted
- 28 Jul 2025
- Last updated
- 9 Apr 2026
- Results posted
- No
Study at a glance
From the registry record, last updated by the sponsor on 9 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Orthognathic Surgery in Anterior Open Bite: a Retrospective Study of 50 Patients With Initial Tongue Malposition
- ClinicalTrials.gov ID
- NCT07520682
- Acronym / sponsor ID
- COBA 50 / 25-5191
- Conditions
- Patients With Anterior Open Bite Malocclusion and Who Benefited of an Orthognathic Surgery, Infantile Swallowing and Tongue Malposition Necessitating Tongue Rehabilitation
- Keywords
- Anterior open bite, Orthognathic surgery, Tongue rehabilitation
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 50 participants (actual)
- Lead sponsor
- Hospices Civils de LyonUniversity, hospital or other
- Study start
- 1 Jan 2022 (actual)
- Primary completion
- 1 Jan 2025 (actual)
- Study completion
- 1 Aug 2025 (actual)
- First posted
- 9 Apr 2026 (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.
The anterior gap is defined by a lack of contact between the upper and lower dental arches.
It is mainly due to the persistence of infantile swallowing during and after childhood, i.e. interposition of the tongue between the two dental arches.
Patients presenting with an anterior gap in adulthood are likely to develop functional sequelae (masticatory difficulties, dental loosening, periodontal disease, etc.) and aesthetic sequelae (edentulous smile, excess height of the lower third of the face compared to the upper and middle third).
Patients who are diagnosed with this condition very often benefit from orthodontic-surgical treatment, comprising a period of orthodontics followed by orthognathic surgery to close the anterior gap. This is combined with lingual re-education to treat infantile swallowing. This lingual re-education is not always carried out, either because infantile swallowing has not been diagnosed, or because of a lack of cooperation on the part of the patient, or because of difficulties in finding a suitable specialist. When rehabilitation is introduced, it is sometimes only after surgery, and for a short time.
For example, it has been observed that among all patients undergoing orthognathic surgery, those with an anterior gap were particularly at risk of surgical treatment failure, or recurrence in the short to medium term.
The main reason cited was the persistence of infantile swallowing and consequent malpositioning of the tongue between the dental arches, creating permanent pressure on the lingual surface of the teeth and eventually leading to recurrence of the gap.
Identifying patient management factors associated with postoperative recurrence of anterior hollowness in patients with infantile swallowing would enable us to adapt the management of these patients.
Study design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Relapse of anterior open bite | – | Other: type of post-operative rehabilitation : with physiotherapy or speech therapyAll patients who presented relapse of anterior open bite after 6 months post operative. |
| No relapse of anterior open bite | – | Other: type of post-operative rehabilitation : with physiotherapy or speech therapyAll patients who did not present a relapse of anterior open bite after 6 months post operative. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- patients undergoing orthognathic surgery with a gap prior to surgery (50 patients)
Key inclusion criteria (4 listed)
- Major patients
- Having undergone ortho gnathic surgery in the Maxillofacial Surgery Department of the Croix Rousse Hospital
- Patients with an anterior gap of more than 3 mm
- Abnormal tongue position at diagnosis
Key exclusion criteria (2 listed)
- Syndromic patients (cleft lip and palate, craniostenosis)
- Patient refusal
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 |
|---|---|---|
| type of post-operative rehabilitation : with physiotherapy or speech therapymean duration of rehabilitation * assess the tongue position at rest, and during speech * assess the surgical movements associated with relapse : advancement, rotation, expansion, genioplasty | Other | No relapse of anterior open bite, Relapse of anterior open bite |
Primary outcome
Measurement of the association between anterior open bite recurrence, defined as the absence of contact between the upper and lower incisors at 6 months postoperatively, and the rehabilitation factors.
Time frame: 6 months
Duration of rehabilitation in months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Apr 2026.
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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Patients With Anterior Open Bite Malocclusion and Who Benefited of an Orthognathic Surgery and Infantile Swallowing and Tongue Malposition Necessitating Tongue Rehabilitation, run by Hospices Civils de Lyon at 1 site in France.
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 4 inclusion and 2 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: finished, as of the sponsor's last update on 9 Apr 2026. 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 France. 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 is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Measurement of the association between anterior open bite recurrence, defined as the absence of contact between the upper and lower incisors at 6 months postoperatively, and the rehabilitation factors. (time frame: 6 months). 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 9 Apr 2026.