Occlusal Adjustments Needed for Michigan Splints Made Using Different Digital Bite Records (AVOAMSDBR)

The Assessment of The Volumetric Occlusal Adjustments Required for Michigan Splints Fabricated Using Various Digital Bite Registrations

This clinical study evaluated digital occlusal recording methods used in the fabrication of Michigan occlusal splints. The objective was to assess whether different digital bite registration techniques influenced the accuracy of occlusal splints and the amount of occlusal adjustment required at clinical fitting.

Participants underwent digital bite registration procedures and received Michigan occlusal splints fabricated using different digital workflows. Follow-up visits were conducted for splint fitting and occlusal assessment. Participant safety and data confidentiality were maintained throughout the study, and all required ethical approvals and risk assessments were obtained prior to study initiation.

The study findings were intended to support improvements in digital dental workflows and enhance the accuracy and efficiency of occlusal splint fabrication.

Study Overview

• Status: Completed
• Conditions: Temporomandibular Disorders (TMD)
• Intervention / Treatment: Device: Digital face-bow, digital bite registration, digital scanning; Device: Digital facebow, digital bite registration, digital scanning; Device: Retruded axis position(RAP with) without a digital facebow

Detailed Description

Background Temporomandibular disorders represented a common clinical condition affecting mandibular function and were frequently associated with parafunctional activities such as bruxism or clenching. Clinical features included orofacial pain, joint sounds, restricted mandibular movement, headaches, dental wear, and occlusal instability. Occlusal splints were commonly prescribed to reduce occlusal loading, protect dental structures, and establish a more favourable mandibular position.

Conventional occlusal splint fabrication relied on physical impressions, mechanical articulation, and manual occlusal adjustment. These processes were time-consuming and technique-sensitive. Digital dentistry introduced alternative workflows incorporating intraoral scanning, virtual articulation, and computer-aided design and manufacturing, with the aim of improving accuracy, reproducibility, and efficiency.

Accurate digital recording of the maxillomandibular relationship remained a critical factor influencing occlusal outcomes. Digital bite registration techniques performed at intercuspal position or centric relation, with or without digital facebow transfer, were expected to affect occlusal accuracy and the extent of chairside adjustment required at delivery.

Virtual articulators were developed to simulate mandibular movements using digitally acquired data. These systems required accurate digital impressions, occlusal records, and appropriate orientation of the maxillary arch relative to craniofacial reference planes. Digital facebow systems enabled virtual transfer of maxillary position and were expected to improve mounting accuracy compared with average-value articulators alone.

Study objectives Primary Objectives

• To evaluate volumetric changes on the occlusal surfaces of Michigan splints following clinical adjustment.
• To compare pre-adjustment and post-adjustment occlusal surface volumes across different digital workflows.
• To assess whether an average-value virtual articulator produced occlusal splints at an increased occlusal vertical dimension without the need for clinical registration.

Secondary objectives

• To assess laboratory efficiency and quality control associated with digital workflows.
• To evaluate clinical time and effort required for occlusal adjustment.
• To assess participant comfort during digital recording procedures.

This was a single-centre clinical study involving 10 participants. Each participant received four Michigan occlusal splints, corresponding to four different digital design workflows based on mandibular recording position and the inclusion or exclusion of a digital facebow record. Each of the four digital designs generated for every participant was manufactured as a separate occlusal splint, resulting in four splints per participant.

Clinical and laboratory procedures Visit 1

• Informed consent was obtained.
• Standardised dental photography was performed.
• A digital facebow record was obtained using a digital facebow system equipped with a scannable bite fork (Axiopresia) as part of the registration process, where applicable. The scannable bite fork was positioned intraorally and digitally captured to record the spatial relationship of the maxillary arch relative to craniofacial reference planes.
• Digital impressions of the maxillary and mandibular arches were obtained using an intraoral scanner under standardised clinical conditions.
• Bite registration at centric relation/ retruded articulation position was obtained following neuromuscular deprogramming using a Lucia gauge and intraoral scanner.
• Bite registration at intercuspal position was recorded using the intraoral scanner.

Laboratory procedures

Using computer-aided design software, four distinct digital occlusal splint designs were produced for each participant based on different combinations of mandibular recording position and digital facebow transfer:

Retruded articulation position (centric relation) with digital facebow record Retruded articulation position (centric relation) without digital facebow record Intercuspal position with digital facebow record Intercuspal position without digital facebow record Each digital design was generated using the same virtual articulator parameters and identical splint design settings, differing only in the mandibular position record and the inclusion or exclusion of the digital facebow data. The resulting designs were then manufactured using three-dimensional printing.

Visit 2: Fitting and occlusal adjustment

• Clinical fitting of the occlusal splints was performed during the second visit.
• Occlusal adjustments were carried out to achieve balanced light occlusal contacts at the resting intercuspal position.
• Lateral movements were assessed to confirm canine guidance, and anterior guidance was evaluated during protrusive movements.
• Any occlusal interferences were identified and removed accordingly to achieve a stable and harmonious occlusal scheme.
• Following completion of occlusal adjustments, the splints were digitally scanned via lab scanner for post-adjustment analysis.

Outcome assessment Pre-adjustment and post-adjustment digital scans of each occlusal splint were imported into three-dimensional analysis software ( Geomagic software). Root mean square deviation values were calculated following best-fit alignment to quantify volumetric changes associated with occlusal adjustment. The 3D and 2D Comparisons at six sections were done ( middle of the cingulum of the right and left central incisor, middle of the cingulum of the right and left canines, messy-buccal cusp to disco-palatal cup of the right and left first molar). Occlusal deviation maps were standardised using consistent colour scales to allow comparison between workflows.

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Sothwarck
    • London, Sothwarck, United Kingdom, SE1 9RT
      • King's College London

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:•

• Aged between 18 and 65.
• Able to provide informed consent.
• Have no more than one tooth missing per quadrant.

Exclusion Criteria:

• Patients with removable dentures
• Patients receiving medication for psychological disorders.
• Patients diagnosed with systemic joint disorders.
• Pregnant.
• Patients who have received TMD treatment in the last 6 months.
• Deep bite cases.
• Those who have an extreme class 3 dental or skeletal relationship.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Health Services Research
• Allocation: Non-Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Retruded axis position(RAP with) without a digital facebow; Each participant received Michigan occlusal splints fabricated using digital bite registration methods, including Retruded axis position(RAP with) without a digital facebow. Participants try each splint in a crossover manner while being blinded to the recording method used. Occlusal accuracy and adjustment requirements are evaluated using three-dimensional surface superimposition and root mean square (RMS) deviation analysis.	Device: Digital face-bow, digital bite registration, digital scanning; The intervention involves the fabrication of Michigan occlusal splints using different digital bite registration workflows. Each participant undergoes digital occlusal recording in centric relation (CR) and intercuspal position (ICP), with and without the use of an Axioprisa® digital facebow, and articulation is performed using Axioprisa® virtual articulator. Four splints are fabricated per participant based on these recordings. Participants are blinded to the recording method used for each splint and try all splints in a crossover manner. Occlusal accuracy and adjustment requirements are evaluated using three-dimensional surface superimposition and root mean square (RMS) deviation analysis.
Experimental: Retruded axis position(RAP) with a digital facebow.; Each participant received Michigan occlusal splints fabricated using digital bite registration methods, including Retruded axis position(RAP) with a digital facebow. Participants try each splint in a crossover manner while being blinded to the recording method used. Occlusal accuracy and adjustment requirements are evaluated using three-dimensional surface superimposition and root mean square (RMS) deviation analysis.	Device: Digital facebow, digital bite registration, digital scanning; The intervention involves the fabrication of Michigan occlusal splints using different digital bite registration workflows. Each participant undergoes digital occlusal recording in centric relation (CR) and intercuspal position (ICP), with and without the use of an Axioprisa® digital facebow, and articulation is performed using Axioprisa® virtual articulator. Four splints are fabricated per participant based on these recordings. Participants are blinded to the recording method used for each splint and try all splints in a crossover manner. Occlusal accuracy and adjustment requirements are evaluated using three-dimensional surface superimposition and root mean square (RMS) deviation analysis.
Experimental: Intercuspal position (ICP) with a digital facebow; Each participant received Michigan occlusal splints fabricated using digital bite registration methods, including maximum intercuspal position (ICP) with a digital facebow. Participants try each splint in a crossover manner while being blinded to the recording method used. Occlusal accuracy and adjustment requirements are evaluated using three-dimensional surface superimposition and root mean square (RMS) deviation analysis.	Device: Retruded axis position(RAP with) without a digital facebow; The intervention involves the fabrication of Michigan occlusal splints using different digital bite registration workflows. Each participant undergoes digital occlusal recording in centric relation (CR) and intercuspal position (ICP), with and without the use of an Axioprisa® digital facebow, and articulation is performed using Axioprisa® virtual articulator. Four splints are fabricated per participant based on these recordings. Participants are blinded to the recording method used for each splint and try all splints in a crossover manner. Occlusal accuracy and adjustment requirements are evaluated using three-dimensional surface superimposition and root mean square (RMS) deviation analysis.
Experimental: Intercuspal position (ICP) without a digital facebow.; Each participant received Michigan occlusal splints fabricated using digital bite registration methods, including maximum intercuspal position (ICP) without a digital facebow. Participants try each splint in a crossover manner while being blinded to the recording method used. Occlusal accuracy and adjustment requirements are evaluated using three-dimensional surface superimposition and root mean square (RMS) deviation analysis.	Device: Digital face-bow, digital bite registration, digital scanning; The intervention involves the fabrication of Michigan occlusal splints using different digital bite registration workflows. Each participant undergoes digital occlusal recording in centric relation (CR) and intercuspal position (ICP), with and without the use of an Axioprisa® digital facebow, and articulation is performed using Axioprisa® virtual articulator. Four splints are fabricated per participant based on these recordings. Participants are blinded to the recording method used for each splint and try all splints in a crossover manner. Occlusal accuracy and adjustment requirements are evaluated using three-dimensional surface superimposition and root mean square (RMS) deviation analysis.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Volumetric occlusal adjustment of michigan occlusal splints	The primary outcome was the volume of occlusal adjustment required for Michigan occlusal splints fabricated using different digital bite registration workflows. Volumetric changes were quantified by calculating root mean square (RMS) deviation values between pre-adjustment and post-adjustment digital scans of each splint using three-dimensional surface comparison software. Higher RMS values indicated greater occlusal adjustment.	Baseline (pre-adjustment) and at splint fitting (post-adjustment)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Occlusal contact quality after adjustment of michigan occlusal splints	The secondary outcome was the qualitative assessment of occlusal contact quality following clinical adjustment of Michigan occlusal splints fabricated using different digital workflows. Occlusion was assessed clinically to confirm balanced light contacts at the resting intercuspal position, presence of canine guidance during lateral excursions, presence of anterior guidance during protrusive movements, and elimination of occlusal interferences. Outcomes were recorded as achievement of a stable and clinically acceptable occlusal scheme following adjustment.	At splint fitting visit

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pattern of occlusal adjustment on splints after fitting	This outcome examined where occlusal adjustments occurred on Michigan occlusal splints after clinical fitting. Digital scans of each splint taken before and after adjustment were compared using computer software to show areas where material was removed. The comparison included both an overall surface assessment and simple two-dimensional comparisons at the front (anterior) and back (posterior) areas of the splint. This helped describe how occlusal adjustments were distributed across different parts of the splint for each digital design.	Baseline (before adjustment) and at splint fitting

Collaborators and Investigators

• Sponsor: King's College London
• Collaborators: Guy's Hospital

Publications and helpful links

General Publications

• Obrez A, et al. Accuracy of opening the vertical dimension on virtual articulators. J Prosthodont. 2019.
• 1-Gross MD. The facebow: Use, misuse, and abuse. J Prosthet Dent. 1982;48:377-382.

Helpful Links

• Clinical trial ethics websute

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2024
• Primary Completion (Actual): December 1, 2025
• Study Completion (Actual): December 15, 2025

Study Registration Dates

• First Submitted: January 5, 2026
• First Submitted That Met QC Criteria: January 14, 2026
• First Posted (Actual): January 21, 2026

Study Record Updates

• Last Update Posted (Actual): January 26, 2026
• Last Update Submitted That Met QC Criteria: January 23, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Michigan splint; Digital occlusal recording; Digital bite registration; Occlusal splint fabrication; Occlusal splint accuracy; Digital facebow; Virtual articulator; Three-dimensional printing
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Stomatognathic Diseases; Muscular Diseases; Joint Diseases; Jaw Diseases; Mandibular Diseases; Craniomandibular Disorders; Temporomandibular Joint Disorders
• Other Study ID Numbers: 43439; HR2301469 (Other Grant/Funding Number: The Hashemite university of Jordan)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared due to the small sample size and the potentially identifiable nature of dental imaging and 3D surface data. Aggregate, anonymised results will be reported.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No