Accuracy of Digital Mandibular Repositioning in Occlusal Reconstruction for Patients With Disc Displacement

Fujian Medical University

Status: Completed

Conditions: Temporomandibular Joint Disc Displacement

Treatments: Device: Clinical Clicking Elimination Repositioning Splint; Device: CAD-Designed Anatomical Repositioning Splint; Device: Adjustable Articulator Repositioning Splint; Device: Electronic Jaw Tracking Repositioning Splint

Study type: Interventional

Funder types: Other

Identifiers

NCT07345104

2024GGA070

Details and patient eligibility

About

This study evaluates a new, individualized treatment for adolescents with temporomandibular joint disorders (TMD) caused by bilateral, reducible disc displacement. Participants will undergo clinical and imaging examinations, including cone-beam CT (CBCT), MRI, and intraoral digital scanning to create three-dimensional models of the teeth and jaw. Based on these data, the study team will design and fabricate a personalized repositioning digital occlusal splint for each participant. Patients will be instructed on how to wear the splint and will return for regular follow-up visits to monitor symptoms and adjust the splint as needed. The study aims to improve pain, chewing function, and overall quality of life. All research-related imaging, digital scans, splint fabrication, and follow-up visits will be provided at no cost to participants. Possible risks include temporary discomfort or pressure when first wearing the splint, and the possibility that symptoms may not improve as expected. Participant safety, privacy, and data confidentiality will be strictly protected, and participants may withdraw from the study at any time without affecting their future medical care.

Full description

Detailed Description This study evaluates four different methods for mandibular repositioning in patients with bilateral reducible temporomandibular joint (TMJ) disc displacement requiring occlusal reconstruction.

Methods of Mandibular Repositioning:

1. Intraoral Direct Positioning Group: The therapeutic jaw position is determined clinically using the clicking elimination method, where patients open wide until clicking occurs, then gradually retract the mandible while performing opening-closing movements to find the minimal protrusion position without clicking.
2. Articulator Positioning Group: Uses mechanical facebow transfer and semi-adjustable articulator (Artex CR) with condylar guidance parameters obtained from protrusive and lateral excursion records. The therapeutic position is determined by analyzing CBCT joint space measurements and MRI disc displacement data.
3. Digital Anatomical Positioning Group: Combines intraoral scanning data with CBCT-reconstructed 3D jaw models. The therapeutic position is determined by referencing MRI disc reduction phase, optimal joint space ratios, and anatomical landmarks using CAD software (Exocad).
4. Digital Jaw Motion Tracking Group: Integrates 3D jaw models with electronic jaw tracking data (Zebris). The therapeutic position is determined by analyzing condylar movement trajectories (identifying the "figure-8" pattern crossover points indicating disc displacement) combined with dynamic MRI and optimal joint space parameters.

Treatment Protocol: All groups receive digitally designed and manufactured repositioning splints. Patients wear splints 24 hours daily (except during meals) for 3 months, with follow-up adjustments at 2 weeks, 1 month, 2 months, and 3 months.

Imaging Protocol:

• CBCT (I-CAT FLX): 120 kV, 5 mA, 0.2 mm resolution
• MRI (GE Discovery MR750w 3.0T): Bilateral TMJ surface coils, oblique sagittal and coronal views in closed-mouth position, oblique sagittal in maximum opening

Assessment Methods:

• Joint space measurements using Ikeda's method on registered pre- and post-treatment CBCT images
• Condyle position analysis using Gelb 4/7 position criteria
• Disc-condyle angle measurement on MRI (>15° defined as disc displacement)

Enrollment: 48 patients

Sex: All

Volunteers: No Healthy Volunteers

Inclusion criteria

1. Diagnosis of reducible temporomandibular joint (TMJ) disc displacement according to the 2014 revised criteria of the International Association for Dental Research;
2. Bilateral reducible disc displacement confirmed by MRI;
3. Reproducible joint clicking during mandibular opening and closing;
4. Permanent dentition with full cognitive and communicative ability;
5. Signed informed consent with good treatment compliance.

Exclusion criteria

1. Non-reducible disc displacement, osteoarthrosis, isolated myofascial pain, or other conditions not meeting diagnostic criteria;
2. Receipt of other TMJ disorder treatments within the past 3 months;
3. Presence of systemic diseases, psychiatric disorders, or impaired consciousness.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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48 participants in 4 patient groups

Intraoral Direct Positioning

Active Comparator group

Description:

Therapeutic mandibular position is determined using the clinical clicking elimination method. Patients perform wide opening until clicking occurs, then gradually retract the mandible while making opening-closing movements to identify the minimal protrusion position without clicking. A repositioning splint is fabricated based on this position.

Treatment:

Device: Clinical Clicking Elimination Repositioning Splint

Articulator Positioning

Experimental group

Description:

Therapeutic mandibular position is determined using a semi-adjustable articulator (Artex CR) with mechanical facebow transfer. Condylar guidance angles are obtained from protrusive and lateral excursion records. The optimal position is calculated based on CBCT joint space measurements and MRI disc displacement data. A repositioning splint is fabricated accordingly.

Treatment:

Device: Adjustable Articulator Repositioning Splint

Digital Anatomical Positioning

Experimental group

Description:

Therapeutic mandibular position is determined by integrating intraoral scanning data with CBCT-reconstructed 3D jaw models using CAD software (Exocad). The optimal position is calculated by referencing MRI disc reduction phase, ideal joint space ratios (anterior:superior:posterior = 1:1.3:1), and anatomical landmarks. A repositioning splint is digitally designed and 3D-printed.

Treatment:

Device: CAD-Designed Anatomical Repositioning Splint

Digital Jaw Motion Tracking

Experimental group

Description:

Therapeutic mandibular position is determined by integrating 3D jaw models with electronic jaw tracking data (Zebris JMA system). The optimal position is identified by analyzing condylar movement trajectories, specifically locating the crossover points of the "figure-8" pattern indicating disc displacement, combined with dynamic MRI and joint space parameters. A repositioning splint is digitally designed and 3D-printed.

Treatment:

Device: Electronic Jaw Tracking Repositioning Splint