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OpenTrials
Completed

NCT Number: NCT07538869

Comparison of 3D Printed Metal Fixed Retainer Versus Conventional Fixed Bonded Retainer

Despite the growing diversity of materials used for mandibular fixed retainers, the evidence base remains inconclusive. In particular, conflicting findings have been reported regarding the bond failure of titanium retainers across different evaluation periods, including immediate and 12-month outcomes. Additionally, the emergence of 3D metal-printed retainers has not yet been matched by sufficient clinical evidence, with current data being limited and lacking long-term validation.

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Key information

Conditions

Bond, Pair Behavior Behavior, Animal Consummatory Behavior Pair Bond Sexual Behavior, Animal

Age range

13 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Amany Eltantawy

Giza, Cairo University, Egypt

About this study

In recent years, CAD/CAM technology and 3D printing have introduced new possibilities in orthodontic practice, with expanding applications across various treatment modalities. Additive manufacturing, commonly known as 3D printing, enables the fabrication of objects through the sequential layering of material to produce precise three-dimensional structures. While orthodontists are already familiar with 3D-printed appliances such as clear aligners, the application of these technologies in fixed retention is still evolving. Recent studies have reported the fabrication of customized lingual retainers using CAD/CAM techniques, including nickel-titanium-milled retainers and zirconia bars designed for use as bonded mandibular fixed retainers.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age ≥ 13 years
  • Complete permanent dentition up to second molars
  • Completed Class I orthodontic treatment and requiring a mandibular fixed -bonded retainer
  • No sex predilection.

Exclusion criteria

  • Enamel defects that may compromise bonding (e.g., hypoplasia, fluorosis)
  • Poor oral hygiene
  • Active dental or periodontal pathology at the site of intervention
  • Lingual restorations on mandibular anterior teeth
  • Poor compliance or inability to attend follow-up visits
  • Psychological or medical conditions that may interfere with study participation

Treatment and study plan

bar 3d printed metal fixed retainer

Device

Participants will receive a custom-designed 3D-printed metal fixed retainer. The retainer is digitally designed using intraoral scans and fabricated using metal 3D printing technology to achieve a precise fit tailored to each patient.

Conventional fixed retainer

Device

Participants will receive a conventional fixed bonded lingual retainer (canine-to-canine) fabricated using multistranded stainless steel wire and bonded using standard clinical procedures.

Primary outcomes

  1. bond failure

    Time frame: immediate (within 24 hours after bonding) and at 3, 6, 9, and 12 months

    Bond failure will be assessed clinically by detecting any detachment of the retainer from the tooth surface (number of debonded teeth).

Secondary outcomes

  1. chairside time

    Time frame: Periprocedural (during retainer bonding procedure on Day 1)

    Time measurement will start from the beginning of acid etching of the teeth and end after completion of composite curing for all bonded teeth.

    The duration will be recorded in minutes using a digital stopwatch by an independent assessor using a digital stopwatch (minutes)

  2. wire breakage

    Time frame: Every 3months for 12 months

  3. plaque accumulation

    Time frame: Baseline (before retainer bonding) and at 3, 6, 9, and 12 months

    Plaque accumulation will be assessed using the Silness-Löe Plaque Index, which scores plaque presence on the tooth surface adjacent to the fixed retainer.

    Each tooth will be scored on a scale from 0 to 3:

    0: No plaque

    • Thin film of plaque detectable by probe
    • Moderate accumulation visible to the naked eye
    • Abundant plaque accumulation

    Assessment will be performed by direct intraoral clinical examination using a dental mirror and probe by a calibrated examiner.

    The outcome will be reported as the mean plaque index score per patient at each time point.

  4. posttreatment relapse

    Time frame: Baseline (before retainer bonding) and at 12 months

    Post-treatment relapse will be assessed using Little's Irregularity Index, which measures the linear displacement of the anatomic contact points of the mandibular anterior teeth.

    Relapse will be calculated as the difference in Little's Irregularity Index between baseline (pre-retention) and 12 months follow-up.

Sponsors and collaborators

Lead sponsor

Amany Ibrahim

Other

Registry information

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Apr 20, 2026
Registry last updated
Apr 20, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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