Additive vs Subtractive Manufacturing for Endocrown Fabrication: A 24-Month RCT (ENDO-3D)

Additive Versus Subtractive Manufacturing for Endocrown Fabrication: A Clinical Comparison of 3D-Printed Ceramic-Filled Photopolymer Resin and CAD/CAM Milled Resin Nano-Ceramics Endocrowns in Posterior Teeth - A 24-Month Randomized Controlled Trial

This randomized controlled trial (RCT) compares the 24-month clinical performance of endocrown restorations fabricated by two digital manufacturing pathways: additive manufacturing using 3D-printed ceramic-filled photopolymer resin (VarseoSmile TriniQ, BEGO) versus subtractive computer-aided design/computer-aided manufacturing (CAD/CAM) milling from hybrid nano-ceramic blocks (HC Hard Block, Shofu). Sixty endocrowns will be placed in endodontically treated posterior molars and evaluated using modified United States Public Health Service (USPHS) criteria at 6, 12, and 24 months. The trial is conducted at the Conservative Dentistry Department, Faculty of Dentistry, Cairo University.

Study Overview

• Status: Not yet recruiting
• Conditions: Endodontically Treated Teeth; Tooth, Nonvital; Dental Restoration
• Intervention / Treatment: Device: CAD/CAM Milled HC Hard Block Endocrown; Device: 3D-Printed VarseoSmile TriniQ Endocrown

Detailed Description

Post-endodontic rehabilitation of extensively damaged posterior molars using endocrowns represents a minimally invasive alternative to conventional crown-plus-post-and-core approaches. Digital fabrication has advanced both the precision and reproducibility of endocrown manufacture. While computer-aided design/computer-aided manufacturing (CAD/CAM) milled hybrid ceramic endocrowns are well-validated clinically, prospective clinical data comparing 3D-printed definitive restorations to milled counterparts are absent. This trial employs a parallel-group, 1:1 randomized design with triple blinding of participants, outcome assessors, and statistician. All restorations are delivered using Beautilink SA self-adhesive dual-cure resin cement. The primary outcome is fracture resistance at 24 months; secondary outcomes include retention, marginal adaptation, marginal discoloration, surface texture, anatomic form, color match, secondary caries, fabrication time, and patient satisfaction assessed by Visual Analogue Scale (VAS).

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Dina Ez Mohamed, BDS MSc PhD; Phone Number: 01008007157; Email: dina.ezz@dentistry.cu.edu.eg
• Study Contact Backup: Name: Rawda H Abdelaziz, BDS MSc PhD; Email: rawda.hesham@dentistry.cu.edu.eg

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 25-45 years, male or female
• Endodontically treated molar tooth with radiographically confirmed treatment success and no clinical signs of failure
• Sufficient remaining coronal structure for endocrown preparation: minimum three walls, wall thickness 1.5 mm or greater, pulp chamber depth 3 mm or greater, supragingival preparation margins
• Completely erupted tooth with intact periodontal support
• Minimum of 20 occluding teeth
• Satisfactory oral hygiene status
• Capable of providing written informed consent and committed to scheduled follow-up visits

Exclusion Criteria:

• Diagnosed parafunctional habit or nocturnal bruxism
• Uncontrolled systemic illness or physical disability precluding safe participation
• Heavy tobacco use
• Current or suspected pregnancy
• Periapical disease or radiographic signs of endodontic failure
• Evidence of pathological tooth wear or occlusal erosion
• Moderate-to-severe periodontitis or tooth with hopeless prognosis
• Radiographic or clinical evidence of vertical root fracture
• Impaired decision-making capacity or anticipated non-compliance

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: CAD/CAM Milled Endocrown; Endocrown restoration fabricated by subtractive CAD/CAM milling from HC Hard Block hybrid nano-ceramic (Shofu Inc., Japan), designed using ExoCAD software and milled on a five-axis wet-milling unit. Adhesively cemented using Beautilink SA self-adhesive dual-cure resin cement (Shofu Inc., Japan).	Device: CAD/CAM Milled HC Hard Block Endocrown; Endocrown restoration milled from HC Hard Block hybrid nano-ceramic (Shofu Inc., Japan) using a five-axis wet-milling CAD/CAM unit. Restoration designed with ExoCAD software, finished and glazed per manufacturer protocol, and cemented with Beautilink SA self-adhesive dual-cure resin cement (Shofu Inc., Japan).; Other Names: CAD/CAM Milled Endocrown
Experimental: 3D-Printed Endocrown; Endocrown restoration fabricated by additive manufacturing using VarseoSmile TriniQ ceramic-filled photopolymer resin (BEGO GmbH & Co. KG, Germany), printed on a 4K LCD printer at 30-45 degree build angle, post-cured under nitrogen atmosphere. Adhesively cemented using Beautilink SA self-adhesive dual-cure resin cement (Shofu Inc., Japan).	Device: 3D-Printed VarseoSmile TriniQ Endocrown; Endocrown restoration 3D-printed using VarseoSmile TriniQ ceramic-filled photopolymer resin (BEGO GmbH & Co. KG, Germany) on a 4K LCD printer at 30-45 degree build angle. Post-cured under nitrogen atmosphere, surface glazed, and cemented with Beautilink SA self-adhesive dual-cure resin cement (Shofu Inc., Japan).; Other Names: 3D-Printed Endocrown

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Restoration Fracture Resistance	Assessed using modified USPHS criteria: Alpha = absence of fracture; Bravo = minor chip amenable to repair; Charlie = catastrophic fracture, unrestorable	24 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Retention	Modified USPHS: Alpha = in situ; Bravo = partial displacement; Charlie = complete loss	6, 12, and 24 months
Marginal Discoloration	Modified USPHS: Alpha = absent; Bravo = superficial; Charlie = penetrating	6, 12, and 24 months
Surface Texture	Modified USPHS: Alpha = smooth; Bravo = minor irregularities; Charlie = extensive breakdown	6, 12, and 24 months
Anatomic Form	Modified USPHS: Alpha = conforms to natural contour; Bravo = discrepancy present, dentin intact; Charlie = dentin or base exposed	6, 12, and 24 months
Color Match	Modified USPHS: Alpha = indistinguishable from adjacent tooth; Bravo = minor deviation, clinically acceptable; Charlie = obvious mismatch; Delta = gross color failure	6, 12, and 24 months
Secondary Caries	Modified USPHS: Alpha = absent; Charlie = present	6, 12, and 24 months
Fabrication Time	Time in minutes from CAD design completion to restoration readiness for cementation	Periprocedural
Patient Satisfaction	Visual Analogue Scale 0-100 mm; 0 = entirely dissatisfied, 100 = entirely satisfied	6, 12, and 24 months

Collaborators and Investigators

• Sponsor: Cairo University

Publications and helpful links

General Publications

• Abou-Steit S, Ibrahim SH, Salem M. Three years clinical evaluation of lithium disilicate and hybrid nano-ceramic CAD/CAM endocrowns (randomized clinical trial). Egyptian Dental Journal 2024;70:551-561.

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): June 1, 2028
• Study Completion (Estimated): September 1, 2028

Study Registration Dates

• First Submitted: May 30, 2026
• First Submitted That Met QC Criteria: June 4, 2026
• First Posted (Actual): June 8, 2026

Study Record Updates

• Last Update Posted (Actual): June 8, 2026
• Last Update Submitted That Met QC Criteria: June 4, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Stomatognathic Diseases; Dental Pulp Diseases; Tooth Diseases; Tooth, Nonvital
• Other Study ID Numbers: /4/26 3D-Printed vs CAD/CAM

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