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 (CONTORTHO)

June 3, 2026 updated by: University Hospital, Strasbourg, France

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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

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Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
88

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • France
    • Bas Rhin
      • Strasbourg, Bas Rhin, France, 67000
        • Pôle de Médecine et Chirurgie Bucco-Dentaires

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

11 years and older (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Minimum of 11 years of age
  • At completion of fixed orthodontic therapy
  • Presence of all 6 mandibular canines and incisors

Exclusion Criteria:

  • 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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Supportive Care
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: PUMICING GROUP

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: 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.
Experimental: SANDBLASTING GROUP

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: 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.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
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.
18 months after bonding of the fixed mandibular lingual retainer

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University Hospital, Strasbourg, France

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

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Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 8, 2019

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 20, 2021

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 21, 2021

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 14, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 16, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 17, 2019

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 29, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 3, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 7434

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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