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

Overview

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.

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.