Clinical Trial of Modified Endocrown and Personalized Post-core and Crown for Large-area Tooth Defects After Root Canal Treatment

September 25, 2025 updated by: Nanfang Hospital, Southern Medical University

A Multicenter, Randomized Controlled, Single-blind, Non-inferiority Clinical Trial of Modified Endocrown and Personalized Post Core Combined With Full Crown for Large-area Tooth Defects After Root Canal Treatment

This study intends to adopt a multicenter, randomized controlled, single-blind, non-inferiority clinical trial design. 246 premolars that meet the inclusion criteria after complete root canal treatment will be selected from the clinical practice and randomly divided into two groups. One group will be restored with the modified endocrown, and the other group will be restored with personalized post and core combined with full crown. Follow-up visits were conducted at 6 months, 1 year and 2 years after the operation respectively. Through clinical and imaging examinations, the survival rates of the two different restorations were evaluated and used as the main evaluation indicators to fill the gap in efficacy data of the modified endocrown in clinical applications, providing a strong evidence-based medical basis for subsequent restoration improvement and standardized application.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
246

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Locations

  • China
      • China, China
        • Recruiting
        • Nanfang Hospital of Southern Medical University
        • Contact:

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • 1: The affected tooth was a premolar that had undergone complete root canal treatment for two weeks. Both imaging and clinical examinations indicated no abnormal periapical reactions.

    2: The oral hygiene condition is good. There is no periodontitis or combined periodontal and endodontic lesions with a probing depth greater than 4mm. There are no severe oral bad habits (such as smoking more than 20 cigarettes per day, chewing betel nuts, etc.)

    3: At least 50% of the crown structure should be retained, or at least two crown walls should be retained, and the tooth defect should not be located under the gums or can be aligned with the gums or located above the gums through crown lengthening surgery.

    4: The affected tooth has sufficient root length to ensure a pedicle-crown ratio of at least 1:1 and a root tip closure of at least 3 mm.

    5: The occlusal function is normal.

    6: Treated premolars will not be used as abutments for FPD or RPD restoration.

Exclusion Criteria:

  • 1: Root canal retreatment of the affected tooth.

    2: Loosening > I °, alveolar bone resorption exceeds 1/3 of the root length.

    3: Loss of adjacent teeth and occlusal teeth.

    4: The patient is in the preconception period and the pregnancy period.

    5: Patients with night bruxism, deep overbite, tight occlusion or severe limited mouth opening, and temporomandibular joint diseases.

    6: Patients who have a history of chemotherapy or radiotherapy in the head and neck region within 5 years, suffer from severe systemic and organic diseases, have physical disabilities or mental illnesses that affect oral hygiene care, or have received drug treatment that may affect or promote bone metabolism within the past 3 months.

    7: The affected tooth has imaging manifestations of absorption inside and outside the root, or the anatomical morphology of the root and root canal is poor, such as short and small roots, curved root canals, small roots or residual roots that cannot meet the cord-to-root ratio standard for pile-core crown restoration.

    8: The researchers consider other situations that are not suitable for participation.

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: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: modified endocrown
  1. preparation of residual crown: A. occlusal surface reduction of about 1.5-2mm, hole edge angle rounded;B. root canal orifice extension: remove all decay, remove root canal filling material 2mm below the root canal orifice;C. pulp cavity wall formation: form 2-5° extension of the wall, if there is a concave with mobile resin restoration.
  2. model design: use CEREC digital intraoral scanner
  3. Cutting: using CEREC MCX CAD/CAM system, cutting lithium disilicate glass ceramic block (IPSe. max CAD), fitting modified pulp cavity retention crown on teeth, adjusting occlusion, post-treatment of restoration, bonding with all-acid etching resin cement.
Procedure: modified endocrown
Combining the advantages of post-core crown and endocrown, an modified endocrown was designed
No Intervention: Personalized pile core combined with full crown
  1. Coronal preparation: Remove all existing restorations and carious tissue, eliminate unsupported enamel, flatten the root surface, establish the definitive margin, and ensure the dentin ferrule is ≥1 mm thick and ≥1.5 mm high.
  2. Post-space preparation: Set post depth at ⅔-¾ of root length (≥ clinical crown length) using the working-length and periapical radiograph; remove obturation material to this depth with a pilot drill, leaving ≥4 mm apical seal.
  3. Core restoration: Take a polyether impression of the post space, have a Co-Cr post-and-core fabricated, lute it with self-adhesive resin cement (RelyX U100/U200; 3M-ESPE), then prepare the core for a full crown.
  4. Full-crown fabrication: Record a polyether impression/optical scan, have a lithium-disilicate ceramic crown (IPS e.max CAD) milled, try-in and adjust, then cement definitively with the same self-adhesive resin cement following manufacturer instructions.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
survival rate
Time Frame: 6 month、1 year、2 years
To evaluate secondary caries, proximal anatomy, gingival health, tooth integrity, marginal adaptability, fracture and retention, and radiographic results of the restoration, and to calculate FDI scores for the above indicators according to the World Dental Federation evaluation criteria (FDI), calculate the survival rate of the restoration
6 month、1 year、2 years

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Tooth reserve volume
Time Frame: immediately
After root canal treatment and before tooth preparation, each tooth was scanned by CEREC extraoral scanner before tooth preparation. Each tooth was scanned by CEREC extraoral scanner to obtain an original STL file A before tooth preparation. After tooth preparation, the original STL file A1 after tooth preparation was obtained. The files A and A1 were imported into reverse engineering software (GeomagicControlX2020; Geomagic Inc.), calculated and recorded the amount of tooth preparation tissue of each tooth, and finally statistically analyzed the amount of tooth preparation tissue of the two groups.
immediately
patient satisfaction
Time Frame: 2 years
visual analogue scale，VAS
2 years
Adjust the amount of grinding tissue and the time of occlusal adjustment
Time Frame: immediately
After the prostheses are made, the prostheses are scanned by CEREC extraoral scanner, and each prosthesis will obtain an original STL file B, which will be bonded and fixed, adjusted, and scanned again by the same scanner to obtain the final STL file B1 of the prosthesis. The files B and B1 will be imported into reverse engineering software (Geomagic Control X2020; Geomagic Inc., calculated the adjustment tissue volume of the restoration, recorded the adjustment time during the operation, and finally analyzed the adjustment tissue volume and adjustment time of the two groups of restoration statistically.
immediately

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Nanfang Hospital, Southern Medical University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Stomatological Hospital of Southern Medical University
Guanghua Stomatological Hospital, Sun Yat-sen 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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
August 4, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2029

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 25, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 25, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 3, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
October 3, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 25, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2025

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • NFEC-2025-270

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings