Detachment of Glued Mandibular Post-orthodontic RestraintsCONTORTHONCT03954145
Comparison of Bonding Failure Rates of Fixed Lingual Mandibular Retainers in a French Sample Aged 11 or Older, Comparing Prior Enamel Sandblasting With Conventional Pumice Polishing
A study testing Enamel pumicing before bonding the lingual retainer. and Enamel sandblasting before bonding the lingual retainer. in people with Detachment of Glued Mandibular Post-orthodontic Restraints, run by University Hospital, Strasbourg, France at 1 site in France.
Trial summary
At the completion of orthodontic treatment, the position of the mandibular canines and incisors is being maintained on a routine basis by bonding a multi-braided wire retainer onto their lingual surfaces. Read more about this study
- Who is it for?
- Ages 11 years and older
- Conditions the study is for
- Detachment of Glued Mandibular Post-orthodontic Restraints
- What is being tested?
- Enamel pumicing before bonding the lingual retainer. and Enamel sandblasting before bonding the lingual retainer.
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 88 participants
- Where
- 1 siteFrance
- Study dates
- 8 Oct 2019to 21 May 2021
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 11 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Minimum of 11 years of age
- At completion of fixed orthodontic therapy
- Presence of all 6 mandibular canines and incisors
Who cannot join
- Active decay
- Presence of dental restorations
- Tooth fracture
- Periodontal disease
- Structural anomalies affecting the lingual side of the mandibular incisors and canines
- Cleft lip and palate
- Cranio-facial syndrome
- Inability to obtain the patient informed consent
Trial locations and contacts
1 site in 1 country.
France1 site
Pôle de Médecine et Chirurgie Bucco-Dentaires
Strasbourg, Bas Rhin, 67000
About this study
Official title: Comparison of Bonding Failure Rates of Fixed Mandibular Lingual Retainers in a French Sample Aged 11 or Older Comparing Prior Enamel Sandblasting With Conventional Pumice Polishing
At the completion of orthodontic treatment, the position of the mandibular canines and incisors is being maintained on a routine basis by bonding a multi-braided wire retainer onto their lingual surfaces. One of the adverse events that might occur with time is the debonding of the wire from one or several lower anterior teeth . This event which can unfortunately get unnoticed by the patient can lead to unwanted tooth displacement. When the practionner detects such a debonding, he has to go through a laborious and lengthy procedure to rebond the wire. When on the other hand the patient notices himself such a debonding, he is to call in emergency his practitioner to get his retainer repaired. This leads to emergency visits that are susceptible to affect adversely his timetable. The prevalence of these bonding failures is estimated at 37% at 18 month follow-ups. It has been reported that with prior enamel sandblasting, bonding failure rate is reduced to 8% at 24 month follow-ups. However, no study has reported yet the debonding rate of lower fixed, comparing wires that have been bonded after prior enamel pumicing to those that were put in place after prior enamel sandblasting.
The expected result of this trial is a significantly decrease in bonding failure rate of mandibular lingual retainer when enamel surfaces are initially sandblasted compared to the ones which are pumiced. This reduction would lower the risk of unwanted tooth movement of mandibular incisors and canines after orthodontic treatment and decrease the number of emergency appointments for the patient and the practitioner.
- Being tested
- Enamel pumicing before bonding the lingual retainer., Enamel sandblasting before bonding the lingual retainer.
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Enamel pumicing before bonding the lingual retainer.Procedure or surgery
Lingual surfaces of the lower incisors and canines are pumiced before bonding the lingual retainer.
Teeth are being cleaned using a brush loaded with pumice and mounted on a low speed contra-angle. Teeth are then etched and the multi-braided retainer wire is being bonded with composite onto the lingual surfaces of the lower canines and incisors.
Enamel sandblasting before bonding the lingual retainer.Procedure or surgery
Enamel is being initially prepared through sandblasting the lingual surfaces of the mandibular canines and incisors.
Sandblasting is performed with the help of a MicroEtcher IIATM (Danville) which is projecting 50 μm Al2O3 particles onto the enamel surfaces. Teeth are subsequently etched and the retainer is then being bonded with composite onto the lingual surfaces of the mandibular incisors and canines.
| Study group | Role | What they receive |
|---|---|---|
| PUMICING GROUP | Active comparator | Lingual surfaces of the lower incisors and canines are pumiced before bonding the lingual retainer.
Teeth are being cleaned using a brush loaded with pumice and mounted on a low speed contra-angle.Teeth are then etched and the multi-braided retainer wire is being bonded with composite onto the lingual surfaces of the lower canines and incisors Receives: Procedure: Enamel pumicing before bonding the lingual retainer. |
| SANDBLASTING GROUP | Experimental | Enamel is being initially prepared through sandblasting the lingual surfaces of the mandibular canines and incisors.
Sandblasting is performed with the help of a MicroEtcher IIATM (Danville) which is projecting 50 μm Al2O3 particles onto the enamel surfaces. Teeth are subsequently etched and the retainer is then being bonded with composite onto the lingual surfaces of the mandibular incisors and canines. Receives: Procedure: Enamel sandblasting before bonding the lingual retainer. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants With at Least One Bonding Failure at 18 Months
Participants presenting at least one debonding event of the fixed mandibular lingual retainer during the 18-month follow-up period. A retainer was considered failed if at least one bonded tooth became detached.
Measured: 18 months after bonding of the fixed mandibular lingual retainer
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 May 2019
- Study start8 Oct 2019
- Primary completion20 May 2021
- Study completion21 May 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Detachment of Glued Mandibular Post-orthodontic RestraintsStudies of the same condition, open and under way.
- More trials run by University Hospital, Strasbourg, FranceThe 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Supportive care
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Investigator, Outcomes assessor
- Enrolment
- 88 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Hospital, Strasbourg, France
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03954145
- Sponsor's protocol ID
- 7434
- Acronym
- CONTORTHO
- Status last verified
- Jun 2026
- First submitted
- 14 May 2019
- Last updated
- 29 Jun 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Kamm Q, Phonchareun E, Esquenet M, Rafflenbeul F, Severac F, Bolender Y. Comparison of bonding failure rates of mandibular retainers after 2 enamel preparations - sandblasting vs pumicing: An 18-month randomized controlled trial. Am J Orthod Dentofacial Orthop. 2025 Sep;168(3):262-272. doi: 10.1016/j.ajodo.2025.04.015.
PubMed 40885597
Study at a glance
From the registry record, last updated by the sponsor on 29 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparison of Bonding Failure Rates of Fixed Mandibular Lingual Retainers in a French Sample Aged 11 or Older Comparing Prior Enamel Sandblasting With Conventional Pumice Polishing
- ClinicalTrials.gov ID
- NCT03954145
- Acronym / sponsor ID
- CONTORTHO / 7434
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 88 participants (actual)
- Lead sponsor
- University Hospital, Strasbourg, FranceUniversity, hospital or other
- Study start
- 8 Oct 2019 (actual)
- Primary completion
- 20 May 2021 (actual)
- Study completion
- 21 May 2021 (actual)
- First posted
- 17 May 2019 (actual)
- Results
- Posted 29 Jun 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
At the completion of orthodontic treatment, the position of the mandibular canines and incisors is being maintained on a routine basis by bonding a multi-braided wire retainer onto their lingual surfaces. One of the adverse events that might occur with time is the debonding of the wire from one or several lower anterior teeth . This event which can unfortunately get unnoticed by the patient can lead to unwanted tooth displacement. When the practionner detects such a debonding, he has to go through a laborious and lengthy procedure to rebond the wire. When on the other hand the patient notices himself such a debonding, he is to call in emergency his practitioner to get his retainer repaired. This leads to emergency visits that are susceptible to affect adversely his timetable. The prevalence of these bonding failures is estimated at 37% at 18 month follow-ups. It has been reported that with prior enamel sandblasting, bonding failure rate is reduced to 8% at 24 month follow-ups. However, no study has reported yet the debonding rate of lower fixed, comparing wires that have been bonded after prior enamel pumicing to those that were put in place after prior enamel sandblasting.
The expected result of this trial is a significantly decrease in bonding failure rate of mandibular lingual retainer when enamel surfaces are initially sandblasted compared to the ones which are pumiced. This reduction would lower the risk of unwanted tooth movement of mandibular incisors and canines after orthodontic treatment and decrease the number of emergency appointments for the patient and the practitioner.
Study design
- Primary purpose
- Supportive care
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| PUMICING GROUP | Active comparator | Procedure: Enamel pumicing before bonding the lingual retainer.Lingual surfaces of the lower incisors and canines are pumiced before bonding the lingual retainer. Teeth are being cleaned using a brush loaded with pumice and mounted on a low speed contra-angle.Teeth are then etched and the multi-braided retainer wire is being bonded with composite onto the lingual surfaces of the lower canines and incisors |
| SANDBLASTING GROUP | Experimental | Procedure: Enamel sandblasting before bonding the lingual retainer.Enamel is being initially prepared through sandblasting the lingual surfaces of the mandibular canines and incisors. Sandblasting is performed with the help of a MicroEtcher IIATM (Danville) which is projecting 50 μm Al2O3 particles onto the enamel surfaces. Teeth are subsequently etched and the retainer is then being bonded with composite onto the lingual surfaces of the mandibular incisors and canines. |
Who may qualify
- Ages
- 11 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (3 listed)
- Minimum of 11 years of age
- At completion of fixed orthodontic therapy
- Presence of all 6 mandibular canines and incisors
Key exclusion criteria (8 listed)
- Active decay
- Presence of dental restorations
- Tooth fracture
- Periodontal disease
- Structural anomalies affecting the lingual side of the mandibular incisors and canines
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 |
|---|---|---|
| Enamel pumicing before bonding the lingual retainer.Lingual surfaces of the lower incisors and canines are pumiced before bonding the lingual retainer. Teeth are being cleaned using a brush loaded with pumice and mounted on a low speed contra-angle. Teeth are then etched and the multi-braided retainer wire is being bonded with composite onto the lingual surfaces of the lower canines and incisors. | Procedure or surgery | PUMICING GROUP |
| Enamel sandblasting before bonding the lingual retainer.Enamel is being initially prepared through sandblasting the lingual surfaces of the mandibular canines and incisors. Sandblasting is performed with the help of a MicroEtcher IIATM (Danville) which is projecting 50 μm Al2O3 particles onto the enamel surfaces. Teeth are subsequently etched and the retainer is then being bonded with composite onto the lingual surfaces of the mandibular incisors and canines. | Procedure or surgery | SANDBLASTING GROUP |
Primary outcome
Number of Participants With at Least One Bonding Failure at 18 Months
Time frame: 18 months after bonding of the fixed mandibular lingual retainer
Participants presenting at least one debonding event of the fixed mandibular lingual retainer during the 18-month follow-up period. A retainer was considered failed if at least one bonded tooth became detached.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Jun 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Results publication: PubMed 40885597Kamm Q, Phonchareun E, Esquenet M, Rafflenbeul F, Severac F, Bolender Y. Comparison of bonding failure rates of mandibular retainers after 2 enamel preparations - sandblasting vs pumicing: An 18-month randomized controlled trial. Am J Orthod Dentofacial Orthop. 2025 Sep;168(3):262-272. doi: 10.1016/j.ajodo.2025.04.015.
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?
A study testing Enamel pumicing before bonding the lingual retainer. and Enamel sandblasting before bonding the lingual retainer. in people with Detachment of Glued Mandibular Post-orthodontic Restraints, run by University Hospital, Strasbourg, France 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 3 inclusion and 8 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 29 Jun 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?
Yes. Results are posted in the registry (first posted 29 Jun 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
Number of Participants With at Least One Bonding Failure at 18 Months (time frame: 18 months after bonding of the fixed mandibular lingual retainer). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03954145, which also lists 1 linked publication.
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 29 Jun 2026.