An In-vivo Survival Rate of Different Onlay Materials Placed Over Endodontically Treated Molar Teeth

NCT07753941 | Active Not Recruiting

• 2 other identifiers: 154-202520250217
• Study Type: interventional
• Target: 39
• Locations: 1 country
• Sites: 1

Brief Summary

This study aims to evaluate the survival rates of onlays placed over posterior endodontically treated teeth restored with zirconia, lithium disilicate and lithium disilicate reinforced with zirconia. Additionally, it seeks to identify and assess the failure modes associated with these types of restorations.

Conditions

Dental Restoration Failures

Keywords

Onlays; Endodontically treated molars; Adhesive resin cement; USPHS criteria; Clinical performance

Outcome Measures

Primary Outcomes (1)

• Number and Proportion of Successful Onlay Restorations in Posterior Endodontically Treated Teeth Assessed by the Modified United States Public Health Service (USPHS) Criteria

  Posterior endodontically treated teeth restored with zirconia, lithium disilicate, or zirconia-reinforced lithium disilicate onlays are evaluated by two independent examiners using modified USPHS criteria across 8 parameters: marginal discoloration, secondary caries, marginal integrity, surface texture, restoration fracture, occlusal wear, color match, and aesthetic anatomic form. Each parameter rated Alpha (clinically ideal), Bravo (minor complication, clinically acceptable), or Charlie (major complication requiring renewal). Failure if Charlie on any single parameter. Data will be analyzed using Kaplan-Meier survival estimation. Outcome reported as absolute count and percentage (%) of successful restorations, stratified by material group. Higher percentage indicates better outcome.

  6 months and 12 months post-cementation

Secondary Outcomes (1)

• Frequency and Distribution of Individual Modified USPHS Parameter Ratings (Failure Mode Analysis) Stratified by Onlay Material

  6 months and 1 year post-cementation

Study Arms (3)

Monolithic Zirconia Onlays

EXPERIMENTAL

13 endodontically treated molars restored with monolithic zirconia partial-coverage onlays (Zolid Bion Multilayer). Tooth preparation: rounded shoulder finish line located supragingivally, minimum 1 mm axial reduction, 1.5-2 mm occlusal reduction.Finishing was completed with Al2O3 stones or rubber cups. Impressions were taken using digital scanning technology. Temporary fabrication: The abutment teeth were temporarily restored using Acrytemp (Zhermack, Italy) and temporarily cemented with 3MTM RelyXTM Temp NE Zinc Oxide Non-Eugenol Temporary Cement (3M, Germany).

Device: Monolithic zirconia partial coverage onlays

Lithium Disilicate Onlays

ACTIVE COMPARATOR

13 endodontically treated molars restored with lithium disilicate glass-ceramic onlays (IPS e.max Press). Tooth preparation: rounded shoulder finish line located above the cemento-enamel junction (CEJ), 1.5 mm axial reduction, 2 mm occlusal reduction, rounded internal line angles, 90° cavosurface angles. Finishing was completed with Al2O3 stones or rubber cups. Impressions were taken using digital scanning technology. Temporary fabrication: The abutment teeth were temporarily restored using Acrytemp (Zhermack, Italy) and temporarily cemented with 3MTM RelyXTM Temp NE Zinc Oxide Non-Eugenol Temporary Cement (3M, Germany).

Device: Lithium disilicate partial coverage onlays

Zirconia-Reinforced Lithium disilicate Onlays

EXPERIMENTAL

13 endodontically treated molars restored with zirconia-reinforced lithium disilicate glass-ceramic onlays (Vita Ambria). Tooth preparation: identical to lithium disilicate group: rounded shoulder finish line above the CEJ, 1.5 mm axial reduction, 2 mm occlusal reduction, rounded internal line angles, 90° cavosurface angles. Finishing was completed with Al2O3 stones or rubber cups. Impressions were taken using digital scanning technology. Temporary fabrication: The abutment teeth were temporarily restored using Acrytemp (Zhermack, Italy) and temporarily cemented with 3MTM RelyXTM Temp NE Zinc Oxide Non-Eugenol Temporary Cement (3M, Germany).

Device: zirconia-reinforced lithium disilicate partial coverage onlays

Interventions

Monolithic zirconia partial coverage onlays DEVICE

Endodontically treated molars restored with adhesive onlays. For the monolithic zirconia, material-specific intaglio surface treatments are applied prior to cementation: zirconia onlays receive tribochemical silica-coating with 30µm alumina-coated silica particles (CoJet Sand) at 2.5 bar for 20 seconds, followed by Z-Prime Plus and Ceramic Primer Plus (Clearfil™). Teeth were isolated using rubber dam and Tooth Primer were applied for dentin/enamel. All restorations are definitively cemented with MDP-based dual-cure resin cement (Panavia V5, Kuraray Dental). Restorations are seated, tack-cured, and isolated for 3 minutes.

Also known as: Adhesive resin cement; USPHS criteria; Clinical performance.

Monolithic Zirconia Onlays

Lithium disilicate partial coverage onlays DEVICE

Endodontically treated molars restored with adhesive onlays. For the Lithium disilicate (IPS e.max Press), material-specific intaglio surface treatments are applied prior to cementation: Onlays receive 9% hydrofluoric acid etching, washing, drying, and application of Ceramic Primer Plus (Clearfil™). Teeth were isolated using rubber dam and Tooth Primer were applied for dentin/enamel. All restorations are definitively cemented with MDP-based dual-cure resin cement (Panavia V5, Kuraray Dental). Restorations are seated, tack-cured, and isolated for 3 minutes (or light-cured for translucent onlays).

Also known as: Adhesive resin cement; USPHS criteria; Clinical performance.

Lithium Disilicate Onlays

zirconia-reinforced lithium disilicate partial coverage onlays DEVICE

Endodontically treated molars restored with adhesive onlays. For the zirconia-reinforced lithium disilicate onlays (Vita Ambria), material-specific intaglio surface treatments are applied prior to cementation: Onlays receive 9% hydrofluoric acid etching, washing, drying, and application of Ceramic Primer Plus (Clearfil™). Teeth were isolated using rubber dam and Tooth Primer were applied for dentin/enamel. All restorations are definitively cemented with MDP-based dual-cure resin cement (Panavia V5, Kuraray Dental). Restorations are seated, tack-cured, and isolated for 3 minutes (or light-cured for translucent onlays).

Also known as: Adhesive resin cement; USPHS criteria; Clinical performance.

Zirconia-Reinforced Lithium disilicate Onlays

Eligibility Criteria

• Age: 17 Years - 60 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Patients must have good general health.
• Patients must be 17 to 60 years old.
• Exclusively permanent molar teeth (first or second molars) needing restoration after endodontic therapy.
• The tooth needs adequate residual structure to support an Onlay repair, with minimum of 50% of the coronal structure maintained.
• Absence of Active Caries: The tooth and surrounding teeth ought to be free of illnesses or other agents compromising the restoration.
• Endodontic Status: Radiographic evidence of adequate obturation and the lack of periapical pathology justify the excellent root canal treatment the tooth underwent.
• The tooth and surrounding tissues must show periodontal stability free of evidence of active periodontal disease (probing depth \< 4 mm, lack of movement, and no bleeding following probing).
• The tooth must be in functional occlusion or have a specified occlusal contact with the opposite dentition.
• Patients must have good dental hygiene (plaque index than 20% and gingival index less than 1).
• Participants must show that they are ready to follow the study plan, which calls for maintaining oral hygiene standards and showing attendance to follow-up visits.
• Patients must provide written informed consent to be part in the study.

You may not qualify if:

• The tooth had past treatment with a crown or onlay.
• Patients have any known allergies to the components utilized in the Onlay restoration-that is, composite resin, ceramic, or adhesive compounds.
• Pregnant female participants
• Patients have active periodontal disease
• Teeth with vital pulp therapy

Sponsors & Collaborators

• Yousef Mahmoud Salem: lead

Study Sites (1)

Dental Teaching Clinics at Jordan University of Science and Technology

Irbid, 22110, Jordan

Location

Study Officials

• Yousef Salem

  Jordan University of Science and Technology

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Assistant professor

Model Details: This was a three-arm, parallel-group, randomized controlled trial. The individual molar tooth served as the unit of randomization. The two evaluating examiners were blinded to the material assignment and were not present during cementation or occlusal adjustments; only the treating prosthodontist was unblinded to the intervention. Clinical outcomes were assessed prospectively at 6 months and 1 year using modified USPHS criteria."

Study Record Dates

• First Submitted: July 31, 2026
• First Posted: August 10, 2026
• Study Start: September 1, 2025
• Primary Completion: June 1, 2026
• Study Completion (Estimated): June 1, 2027
• Last Updated: August 10, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, ANALYTIC CODE

Locations

JO (1)