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

Investigation of the 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.

Study Overview

• Status: Recruiting
• Conditions: Tooth Wear; Orthodontic Extrusion
• Intervention / Treatment: Radiation: Low-dose Cone-Beam Computed Tomography

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Belgium
  • Liège, Belgium, 4000
    • Recruiting
    • University Hospital of Liege
    • Contact: Amélie Mainjot; Phone Number: +3243233106; Email: a.mainjot@chuliege.be

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Post-Treatment CBCT, Intraoral Scan, and Modjaw Assessment; All participants treated with the OSNPO protocol undergo additional diagnostic assessments performed specifically for research purposes after completion of their routine clinical treatment. These research-only procedures include: a low-dose, large-field CBCT scan to evaluate tooth movements, vertical facial dimensions, and temporomandibular joint position;; a digital intraoral scan to document occlusal contacts and dental morphology;; a Modjaw 3D jaw-tracking recording to assess mandibular function and occlusal dynamics.

Radiation: Low-dose Cone-Beam Computed Tomography; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Three-dimensional orthodontic tooth movements (linear)	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).	Baseline and end of OSNPO treatment (approximately 1 month)
Three-dimensional orthodontic tooth movements (angular)	Quantification of three-dimensional dental movements induced by the OSNPO protocol, including angular changes assessed on cone-beam computed tomography. Unit of measure : Degrees (°).	Baseline and end of OSNPO treatment (approximately 1 month)
Time required to re-establish functional occlusion	Assessment of the duration needed to re-establish a functional occlusion following OSNPO, considering the initial posterior open bite and the orthodontic mechanics applied.	Baseline and end of OSNPO treatment (approximately 1 month)
Occlusal contacts	Assessment of the number of occlusal contacts	Baseline; 1 month; annually up to 5 years; and at 10 years.
Occlusal contacts stability	Assessment of the stability of occlusal contacts over time	Baseline; 1 month; annually up to 5 years; and at 10 years.
Changes in vertical facial height	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.	Baseline and end of OSNPO treatment (approximately 1 month)
Temporomandibular joint position	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.	Baseline and end of OSNPO treatment (approximately 1 month)
Temporomandibular joint function	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)	Baseline and end of OSNPO treatment (approximately 1 month)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Clinical performance of PICN partial restorations	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).	1 month; annually up to 5 years; 10 years.
Longevity of PICN partial restorations	Evaluation of the longevity of PICN bonded restorations, considering restoration thickness, based on survival (presence vs. failure).	1 month; annually up to 5 years; 10 years.
Oral health-related quality of life (OHIP-49)	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	Baseline; weekly during orthodontic treatment; 1 month; annually up to 5 years; 10 years.
Musculoskeletal symptoms	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).	Baseline; 1 month; annually up to 5 years; 10 years.
Patient satisfaction	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).	1 month

Collaborators and Investigators

• Sponsor: Mainjot Amélie

Publications and helpful links

General Publications

• Hickel R, Peschke A, Tyas M, Mjor I, Bayne S, Peters M, Hiller KA, Randall R, Vanherle G, Heintze SD. FDI World Dental Federation - clinical criteria for the evaluation of direct and indirect restorations. Update and clinical examples. J Adhes Dent. 2010 Aug;12(4):259-72. doi: 10.3290/j.jad.a19262.

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2026
• Primary Completion (Estimated): February 24, 2041
• Study Completion (Estimated): February 24, 2041

Study Registration Dates

• First Submitted: March 4, 2026
• First Submitted That Met QC Criteria: April 14, 2026
• First Posted (Actual): April 16, 2026

Study Record Updates

• Last Update Posted (Actual): April 16, 2026
• Last Update Submitted That Met QC Criteria: April 14, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Orthodontic tooth movement; Minimally invasive dentistry; Localized tooth wear; PICN restorations
• Additional Relevant MeSH Terms: Stomatognathic Diseases; Tooth Diseases; Tooth Wear
• Other Study ID Numbers: B7072025000111

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No