This Study is Conducted to Evaluate the Clinical Performance of Indirect Overlay Restorations With Different Cavity Preparation Designs in Endodontically Treated Molars.

May 22, 2026 updated by: Sara Ibrahim Mohamed Fahmy, Cairo University

A Prospective Clinical Evaluation of Indirect Overlay Restorations With Different Cavity Preparation Designs in Endodontically Treated Molars: Two Year Randomized Clinical Trial

This study is conducted to evaluate the clinical performance of indirect overlay restorations with different cavity preparation designs in endodontically treated molars over two years.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

First Validation of endodontic treatment using a periapical radiograph and proper history taking.

{I}• Cavity Preparation Procedures for Comparator Group:

  • Removal of any remnants of temporary filling and excess gutta percha to the level of root canal orifice.
  • Removal of all undermined enamel.
  • Then 1.5 to 2 mm cusp reduction will be performed for the buccal and lingual walls.
  • The occlusal box will be of 2.5 mm width, 2 mm depth cavity walls and will be flared to produce a 6 degree of divergence.
  • The cavity will have internal rounded angles, finished enamel with sharp non-beveled margins and smooth well-defined walls.
  • Immediate Dentin Sealing and Cavity Optimization: Immediate dentin sealing will be performed through the use of a universal adhesive followed by the injection of injectable flowable resin composite. Blocking of undercuts using injectable flowable resin composite and margin elevation if required.
  • The final retentive design will include occlusal clearance of 2 mm with occlusal box cavity of depth 2 mm with all margins in enamel occlusally and all dentin surfaces will be covered.

{II}• Cavity Preparation Procedures for Intervention Group:

  • Removal of any remnants of temporary filling and excess gutta percha to the level of root canal orifice.
  • No additional removal of the tooth structure will be performed at this step.
  • Cavity optimization will be performed first.
  • Blocking of undercuts using injectable flowable resin composite and margin elevation if required.
  • The occlusal cavity will be restored during cavity optimization with injectable resin composite to reduce the areas of dentin exposure and preserve the remaining tooth structure.
  • The dentin substitute resin composite will establish the biobase.
  • An anatomical non retentive preparation design will be performed to show continuous inclined plane preparation with 2 mm cuspal reduction, concave chamfer margins, and 1 to 1.5 mm thick butt-joint preparation in the interproximal portion.

  • The final cavity design will include occlusal clearance of 2 mm with total cusp coverage, with biomimetic features (anatomical, non-retentive design) with no occlusal box cavity.

    • The CAD/CAM partial coverage overlay restoration will be designed, then milled using SHOFU Hard hybrid ceramic blocks for both groups following its design.
    • Cementation for both groups:
  • Selective etching of the enamel margins of the cavity will be made using 37% phosphoric acid.
  • Application of Universal Adhesive according to manufacturer's instructions and cured.
  • Regarding the milled indirect overlay restorations; surface roughening with Dura-Green Stones SHOFU will be performed, followed by the application of a suitable priming agent, then the injection of resin cement in the fitting surface, and finally the restoration will be cemented.
  • Restoration will be placed onto the prepared cavities allowing for excess resin cement to emerge which will then be tac-cured for 5 second using a standard intensity light cure allowing for slight hardening of the excess resin cement.
  • Removal of excess cement using a sharp explorer, excavator or a c-blade along with the use of interdental flossing to ensure elimination of interdental excess resin cement material.
  • Completing the remaining curing cycle after excess removal to the full curing time.

Study Type

Interventional

Enrollment (Estimated)

50

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

Patient Related Criteria:

  • Adult patients (age: 20-60 years) of both genders.
  • Healthy patients (not suffering of any systematic or chronic diseases).
  • Able to tolerate the necessary restorative procedures.
  • Willing to sign the informed ethical consent.
  • Accepts the follow-up period.

Tooth Related Criteria:

  • Proper endodontically treated teeth.
  • First and second permanent molars.
  • Absence of any peri-apical lesions.
  • Absence of any periodontal disease involvement.
  • Large access cavities with one or two missing walls.
  • Patients with proper oral hygiene.
  • Presence of opposing tooth.

Exclusion Criteria:

  • Patient related:
  • Patients younger than 20 or older than 60 years old.
  • Pregnant females.
  • Patients with any systemic or chronic diseases.
  • Patients not accepting the follow-up period.
  • Patients not willing to sign the informed ethical consent.
  • Patients with known allergies to latex and/or resinous material.

Tooth related

  • Endodontically treated anterior, premolar and third molar teeth.
  • Hopelessly carious/destructed teeth necessitating extraction.
  • Mobile teeth, indicating periodontal disease or trauma.
  • External or internal resorption.
  • Poor endodontic treatment.
  • Periapical lesion present.
  • Cervical carious lesions involved.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: conventional retentive overlay design
Other: hybrid ceramic retentive overlay
Endodontically treated molars will receive indirect overlay restorations utilizing a conventional retentive occlusal box cavity design.
Experimental: minimal invasive non-retentive overlay design
Other: hybrid ceramic non-retentive overlay
Endodontically treated molars will receive indirect overlay restorations utilizing a minimal invasive anatomical non-retentive design.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Marginal adaptation (success rate)
Time Frame: T0: baseline T1: 6 months T2: 12 months T3: 18 months T4: 2 years

Measuring device:

Modified FDI criteria,

Measuring unit:

Ordinal Data (scores)
T0: baseline T1: 6 months T2: 12 months T3: 18 months T4: 2 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
proximal contact point 3.fracture of material and retention 4.wear 5. marginal staining 6. color match 7.caries at restoration margin
Time Frame: T0: baseline T1: 6 months T2: 12 months T3: 18 months T4: 2 years

Measuring device:

Modified FDI criteria,

Measuring unit:

Ordinal Data (scores)
T0: baseline T1: 6 months T2: 12 months T3: 18 months T4: 2 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Cairo University

Investigators

  • Study Director: Olfat ElSayed Hassanein, Professor, Conservative Dentistry, Faculty of Dentistry, Cairo University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 15, 2026

Primary Completion (Estimated)

June 15, 2028

Study Completion (Estimated)

August 15, 2028

Study Registration Dates

First Submitted

May 19, 2026

First Submitted That Met QC Criteria

May 22, 2026

First Posted (Actual)

May 29, 2026

Study Record Updates

Last Update Posted (Actual)

May 29, 2026

Last Update Submitted That Met QC Criteria

May 22, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 12041994

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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