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NCT Number: NCT07533240

Orthodontic and Articular Effects of the One-Step No-Prep Protocol

This study investigates how the One-Step No-Prep protocol with orthodontic assistance affects dental and jaw function in adults treated for localized tooth wear. It focuses on the predictability and extent of orthodontic tooth movements, the impact on temporomandibular joint position and function, and the quality and long-term stability of the restored bite.

Participants will receive minimally invasive bonded restorations combined with simple orthodontic mechanics. The study will evaluate changes in tooth position, bite contacts, facial vertical height, and temporomandibular joint function using digital scans, low-dose 3D imaging, jaw-tracking, and clinical examinations. Patient comfort, function, and satisfaction will also be assessed through questionnaires.

The goal is to better understand how this conservative treatment performs over time.

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Key information

Conditions

Tooth Wear Orthodontic Extrusion Stomatognathic Diseases Tooth Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University Hospital of Liège

Liège, 4000, Belgium

Location status: Recruiting

Location contact

Amélie Mainjot

CONTACT

[email protected]

+3243233106

About this study

This study evaluates the clinical, orthodontic, and functional outcomes of the One-Step No-Prep protocol with orthodontic assistance (OSNPO) in adult patients presenting with localized tooth wear. The OSNPO approach combines bonded restorations placed without tooth preparation and controlled orthodontic extrusion to re-establish posterior occlusion. Although the protocol has shown promising clinical results, several key aspects have not yet been quantified or documented systematically.

The study includes both prospective and retrospective participants treated at the University Hospital of Liège. Prospective cases undergo standardized digital assessments, including intraoral scanning, low-dose cone-beam CT, and 3D jaw-tracking, while retrospective cases contribute long-term clinical and occlusal data. Follow-up extends to 5 years, with an additional evaluation at 10 years.

The primary focus is to characterize the nature and magnitude of orthodontic tooth movements, the time required to regain full occlusion, and the short- and long-term stability of occlusal contacts after treatment. Additional analyses examine changes in vertical facial dimensions, as well as temporomandibular joint position and function before and after treatment. Secondary outcomes include the clinical performance of PICN restorations and patient-reported measures of comfort, function, esthetics, and quality of life.

By integrating digital imaging, functional analysis, and patient-centered outcomes, this study aims to clarify the biological mechanisms underlying OSNPO, identify predictors of treatment duration and stability, and support evidence-based use of this minimally invasive protocol in the management of tooth wear.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Localized tooth wear that will be treated, or has already been treated, using the OSNPO protocol.
  • Age 18 years or older.
  • Sufficient cognitive ability to understand the study procedures and complete the required assessments.
  • Ability to read and complete the study questionnaires in French.
  • Written informed consent provided.

Exclusion criteria

  • No exclusion criteria.

Treatment and study plan

Low-dose Cone-Beam Computed Tomography

Radiation

Acquisition of a low-dose, large-field CBCT scan performed specifically for research purposes after completion of the OSNPO treatment, used to assess tooth movements, vertical facial dimensions, and temporomandibular joint position.

Primary outcomes

  1. Three-dimensional orthodontic tooth movements (linear)

    Time frame: Baseline and end of OSNPO treatment (approximately 1 month)

    Quantification of three-dimensional dental movements induced by the OSNPO protocol, including linear changes assessed on cone-beam computed tomography.

    Unit of measure : Millimeters (mm).

  2. Three-dimensional orthodontic tooth movements (angular)

    Time frame: Baseline and end of OSNPO treatment (approximately 1 month)

    Quantification of three-dimensional dental movements induced by the OSNPO protocol, including angular changes assessed on cone-beam computed tomography.

    Unit of measure : Degrees (°).

  3. Time required to re-establish functional occlusion

    Time frame: Baseline and end of OSNPO treatment (approximately 1 month)

    Assessment of the duration needed to re-establish a functional occlusion following OSNPO, considering the initial posterior open bite and the orthodontic mechanics applied.

  4. Occlusal contacts

    Time frame: Baseline; 1 month; annually up to 5 years; and at 10 years.

    Assessment of the number of occlusal contacts

  5. Occlusal contacts stability

    Time frame: Baseline; 1 month; annually up to 5 years; and at 10 years.

    Assessment of the stability of occlusal contacts over time

  6. Changes in vertical facial height

    Time frame: Baseline and end of OSNPO treatment (approximately 1 month)

    Assessment of the variation in vertical facial height induced by the OSNPO protocol, measured on cone-beam computed tomography. The assessment includes linear measurements between anatomical landmarks.

  7. Temporomandibular joint position

    Time frame: Baseline and end of OSNPO treatment (approximately 1 month)

    Assessment of the changes in temporomandibular joint position following the OSNPO protocol. Joint position is evaluated using cone-beam computed tomography, with measurements between anatomical landmarks.

  8. Temporomandibular joint function

    Time frame: Baseline and end of OSNPO treatment (approximately 1 month)

    Assessment of the changes in temporomandibular joint function following the OSNPO protocol assessed using the Modjaw jaw-tracking system. Functional evaluation includes three-dimensional mandibular dynamics recorded during different mandibular movements, captured in real time.

    Unit of measure : Movement amplitudes in millimeters (mm)

Secondary outcomes

  1. Clinical performance of PICN partial restorations

    Time frame: 1 month; annually up to 5 years; 10 years.

    Evaluation of the clinical quality of PICN bonded restorations using standardized FDI (World Dental Federation) criteria, considering restoration thickness.

    Unit of measure : FDI score (1-5; higher scores indicate poorer performance).

  2. Longevity of PICN partial restorations

    Time frame: 1 month; annually up to 5 years; 10 years.

    Evaluation of the longevity of PICN bonded restorations, considering restoration thickness, based on survival (presence vs. failure).

  3. Oral health-related quality of life (OHIP-49)

    Time frame: Baseline; weekly during orthodontic treatment; 1 month; annually up to 5 years; 10 years.

    Evaluation of the impact of the OSNPO protocol on oral health-related quality of life measured with the OHIP-49 (Oral Health Impact Profile) questionnaire.

    Unit of measure : Scale 1-5; higher scores indicate worse quality of life

  4. Musculoskeletal symptoms

    Time frame: Baseline; 1 month; annually up to 5 years; 10 years.

    Evaluation of musculoskeletal discomfort related to the craniofacial, cervical and upper-body regions using the Nordic Musculoskeletal Questionnaire.

    Unit of measure : Nordic score (0-10 per region; higher scores indicate more severe symptoms).

  5. Patient satisfaction

    Time frame: 1 month

    Assessment of patient satisfaction regarding comfort, esthetics, function, and overall experience with the OSNPO protocol.

    Unit of mesure : Satisfaction score (1-10; higher scores indicate greater satisfaction).

Sponsors and collaborators

Lead sponsor

Mainjot Amélie

Other

Registry information

Official study title

Investigation of the Orthodontic and Articular Effects of the One-Step No-Prep Protocol

Acronym: OSNPO

Important dates

Study start
2026
Primary completion
2041
Study completion
2041
First posted
Apr 16, 2026
Registry last updated
Apr 16, 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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