Clinical Assessment of Dynamic and Static Occlusal Contacts in Direct and Indirect Posterior Restorations

Conventional clinical evaluation of dental occlusion relies predominantly on qualitative indicators such as articulating papers, metallic foils, and silicone-based materials and the accuracy of these indicators may be influenced by material thickness, moisture contamination, and subjective interpretation. Quantitative assessment of occlusal contacts in direct and indirect posterior restorations may help clinicians to establish and maintain harmonious and proper dental occlusion. To assess the level of static and dynamic occlusal contact surfaces in direct and indirect restorations, clinically and quantitatively. Also, to compare outcomes between clinicians with two different levels of clinical experience, immediately and one month after the restorative procedures. Patients requiring restoration for maxillary or mandibular first molars were treated either with direct nanohybrid resin composite (Neo Spectra ST HV A2, Dentsply) restorations or indirect restorations using computer-aided design/computer-aided manufacturing (CAD/CAM) method with hybrid ceramic material (Cerasmart 270 HT A2, GC). The direct (n =30) and indirect (n=30) restorations of postgraduate clinicians and direct restorations (n=30) of undergraduate clinicians (5th grade) were compared immediately (T1) and one month (T2) after the restorative procedures. A single dental technician performed the digital design and the milling of all indirect restorations. Static and dynamic occlusal contact surfaces of the teeth were quantitatively assessed through the collected digital scans by an intraoral scanner (iTero Element 5D, Align), using a computer software program (ChairsideCAD 3.1, Exocad, Align), by setting contact distances to 10, 50, 100, 150, 200, 250, 300, and 350 μm, gradually. The static contacts were assessed by calculating the percentage of the occlusal contact surfaces to the entire occlusal contact surface for each restored tooth, using the ImageJ software program (National Institutes of Health). The dynamic contacts were assessed according to the presence (positive) or absence (negative), regarding 4 lateral movements of the mandibular arch (0.5, 1, 2, and 3 mm on the working side) using a virtual articulator integrated to the ChairsideCAD.

Study Overview

• Status: Completed
• Conditions: Occlusal Analysis

Detailed Description

The study was conducted on patients who applied to the undergraduate and postgraduate clinics of the Department of Restorative Dentistry, Marmara University Dentistry Faculty. The number of teeth to be included in the study was determined by Statistical Power Analysis (G-Power Analysis). With 90% confidence (1-α), 85% test power (1-β), and an effect size of f =0.276, the total number of teeth to be included in the study for 3 groups was determined to be a minimum of 90. Patients aged between 17 and 45 requiring restoration of maxillary or mandibular first molar teeth were included in the study. The teeth with mesial-occlusal-distal (MOD) cavity preparation encompassing 50% of the intercuspal distance for direct restorations and overlay preparation for indirect restorations were included. The ones having asymptomatic root canal treatments were also included. Those who had caries, crowns, amalgam restorations, fractures, pathological wear, or severe periodontal problems on their maxillary or mandibular first molar teeth were excluded from the study. The patients who had active temporomandibular disorders, missing teeth, primary dentition, posterior disocclusion, posterior crossbite, and anterior openbite were also excluded. Those who were undergoing active orthodontic treatment were excluded from the study. Finally, total of 90 maxillary or mandibular first molars were selected from 45 patients. All the included patients were informed about the study procedures and provided written informed consent before the study.

The restorations were performed using standardized equipment and techniques for the study groups either by a 5th-grade undergraduate clinician or a postgraduate clinician with 5 years of clinical experience. Three application groups were determined according to the type of posterior restoration and clinician. The postgraduate clinician performed 30 direct posterior MOD restorations and 30 indirect overlay restorations, and the undergraduate clinician performed 30 direct posterior MOD restorations.

Intraoral scans of the final direct and indirect restorations were obtained at immediately after and one month recall periods using the Element 5D intraoral scanner. To prevent any unintended change in occlusion, the dental procedures were prohibited for the patients between the first and second intraoral scans. For each patient, full maxillary and mandibular arches and the interocclusal records were scanned and recorded by the postgraduate clinician, and the acquired scan data were exported as polygon file format (.PLY). Then 3D digital models of the jaws were transferred to a specific software program (ChairsideCAD 3.1, Exocad, Align), in which the static and dynamic occlusal contacts with the opposing dentition could be visualized. To evaluate static and dynamic occlusal contacts, two different methods were followed.

For static occlusal contacts, after importing .PLY files into ChairsideCAD software program, the tightness of the occlusal contact surfaces was visualized and evaluated by eight occlusal distance grades: 10, 50, 100, 150, 200, 250, 300, and 350 μm. High resolution .PNG images of upper or lower jaws' 3D models were generated from the occlusal plane when the entire occlusal surface and occlusal contact areas were visible. Therefore, 8 different 2D images representing each grade were recorded in high-resolution of 90 teeth immediately after the restorations and one month after the restorations.

For the dynamic occlusal contact surface evaluation, .PLY files were imported to ChairsideCAD 3.1 software program, then 3D models were mounted on a fully adjustable Arcon type virtual articulator (Artex CR, Amann Girrbach) integrated with the software. For the mounting of the maxillary arch model to the articulator, the mesio-incisal embrasure of the upper central teeth and the mesio-buccal tubercle of the left and right upper first molars were selected respectively. The virtual articulator was adjusted to the average value parameters: Bennett angle was set at 10 degrees, immediate side shift was set at 0.5 mm, condylar angle was set at 30 degrees, and incisal table angle was set at 30 degrees as described in a previous research. In the articulator tool of the software program, the lateral movements of 0.5, 1, 2, and 3 mm were set gradually to the working side. The tightness of the occlusal contact surfaces was defined by the same occlusal distances as in static occlusal contacts (10, 50, 100, 150, 200, 250, 300, and 350 µm). The occlusal surface dynamic contacts were assessed as positive (+) or negative (-) for each lateral movement step, for all occlusal distances, immediately after the restorations and one month after the restorations.

• Study Type: Observational
• Enrollment (Actual): 45

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Maltepe
    • Istanbul, Maltepe, Turkey (Türkiye), 34854
      • Marmara University Faculty of Dentistry

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 17 years to 45 years (Child, Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients aged between 17 and 45 requiring restoration of maxillary or mandibular first molar teeth were included in the study. The teeth with mesial-occlusal-distal (MOD) cavity preparation encompassing 50% of the intercuspal distance for direct restorations and overlay preparation for indirect restorations were included. The ones having asymptomatic root canal treatments were also included. Those who had caries, crowns, amalgam restorations, fractures, pathological wear, or severe periodontal problems on their maxillary or mandibular first molar teeth were excluded from the study. The patients who had active temporomandibular disorders, missing teeth, primary dentition, posterior disocclusion, posterior crossbite, and anterior openbite were also excluded. Those who were undergoing active orthodontic treatment were excluded from the study. Finally, total of 90 maxillary or mandibular first molars were selected from 45 patients. All the included patients were informed about the study.

Description

Inclusion Criteria:

• Sufficient cognitive ability to understand the consent process
• 17-45 years old
• Clinically healthy gingiva and periodontal tissues

Exclusion Criteria:

• Missing teeth except third molars
• Ongoing orthodontic or prosthetic treatments that may affect occlusion
• Bruxism

Study Plan

How is the study designed?

Design Details

• Observational Models: CASE_CONTROL
• Time Perspectives: RETROSPECTIVE

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
Postgraduate indirect restoration group; All indirect restorations were single visit, overlay cad/cam restorations using hybrid ceramic blocks (Cerasmart 270 HT A2, GC). Selected maxillary and mandibular vital teeth or teeth with root canal treatment were restored. Non-retentive overlay preparations were performed by the clinicians. Marginal elevation was performed when necessary, using a highly filled flowable composite (Gaenial Universal Injectable A2 shade, GC) and partial precontoured matrix bands (Tor VM). No periodontal surgery, gingival retraction method, or rubber dam isolation was used before the restorations. The immediate dentin sealing procedure was performed for the vital teeth.
Postgraduate direct restoration group; The direct posterior MOD restorations on maxillary and mandibular vital teeth or teeth with root canal treatment were performed by the postgraduate clinicians using a nanoceramic resin composite (Neo Spectra ST HV A2, Dentsply). MOD cavities were prepared without bevels. Following the successful adaptation of precontoured matrix bands (0.050 mm thickness, Tor VM) and wooden wedges to the mesial and distal margins of the cavities, selective enamel etching was applied. Then a universal adhesive agent (G-Premio Bond, GC) was applied according to the manufacturer's instructions. The composite was layered incrementally by starting to shape both marginal walls and then the rest was performed using the cusp-to-cusp technique. Each layer was cured by a calibrated LED curing unit (Elipar Deepcure S, 3M ESPE) for 10 seconds.
Undergraduate direct restoration group; The direct posterior MOD restorations on maxillary and mandibular vital teeth or teeth with root canal treatment were performed by the undergraduate clinicians using a nanoceramic resin composite (Neo Spectra ST HV A2, Dentsply) with the same clinical protocol. MOD cavities were prepared without bevels. Following the successful adaptation of precontoured matrix bands (0.050 mm thickness, Tor VM) and wooden wedges to the mesial and distal margins of the cavities, selective enamel etching was applied. Then a universal adhesive agent (G-Premio Bond, GC) was applied according to the manufacturer's instructions. The composite was layered incrementally by starting to shape both marginal walls and then the rest was performed using the cusp-to-cusp technique. Each layer was cured by a calibrated LED curing unit (Elipar Deepcure S, 3M ESPE) for 10 seconds.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assessment of the level of static occlusal area percentage and dynamic occlusal contact presence of direct and indirect restorations, using ChairsideCAD and imageJ softwares.	Measurements of the level of static and dynamic occlusal contacts for differences of direct and indirect restoration types. Static occlusal contact areas were calculated as ratio of tooth contact area to total occlusal area. Dynamic occlusal contacts were calculated as presence.	Immediately after and 1 month follow-up

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assessment of the clinical experience factor regarding the occlusal contact levels for direct restorations for both static occlusal contact area and dynamic occlusal contact presence, using ChairsideCAD and imageJ softwares.	Measurement of clinical experience factor regarding the occlusal contact level differences of direct postgraduate and direct undergraduate restorations. Static occlusal contact areas were calculated as ratio of tooth contact area to total occlusal area. Dynamic occlusal contacts were calculated as presence.	Immediately after and 1 month follow-up

Collaborators and Investigators

• Sponsor: Marmara University

Study record dates

Study Major Dates

• Study Start (Actual): June 3, 2024
• Primary Completion (Actual): January 13, 2025
• Study Completion (Actual): June 6, 2025

Study Registration Dates

• First Submitted: September 30, 2026
• First Submitted That Met QC Criteria: September 30, 2026
• First Posted (Actual): October 6, 2026

Study Record Updates

• Last Update Posted (Actual): October 13, 2026
• Last Update Submitted That Met QC Criteria: October 7, 2026
• Last Verified: September 1, 2026

More Information

Terms related to this study

• Keywords: Indirect; Occlusal contact; Posterior restoration; Direct
• Other Study ID Numbers: 09.2024.727

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

All data obtained without working will be shared if requested.

Drug and device information, study documents

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