The goal of this clinical trial is to learn whether 3D-printed resin composite endocrowns perform as well as milled resin composite endocrowns in restoring endodontically treated teeth. It will also learn how well the restorations fit over time. The main questions it aims to answer are: Do 3D-printed endocrowns and milled endocrowns show different clinical performance? Do 3D-printed endocrowns and milled endocrowns differ in restoration fit over 18 months? Researchers will compare two fabrication methods: Additive manufacturing: 3D-printed resin composite endocrowns. Subtractive manufacturing: milled resin composite endocrowns. Participants will: Be recruited from the Conservative Dentistry Department, Faculty of Dentistry, October 6 University. Receive tooth preparation after confirmation of satisfactory root canal treatment. Have their teeth prepared using standardized endocrown guidelines by one calibrated operator. Have digital scans taken of the prepared tooth, opposing arch, and bite registration. Have restorations designed digitally and then assigned randomly to one of the two groups. Receive a temporary restoration until the final endocrown is ready. Have the final restoration tried in for fit, contacts, and occlusion before cementation. Have a baseline post-cementation scan taken for fit assessment. Return for follow-up visits at baseline, 6 months, 12 months, and 18 months. Be evaluated at each visit using Modified FDI criteria and 3D digital superimposition for fit analysis.
Eligible participants will be recruited from the Conservative Dentistry Department, Faculty of Dentistry, October 6 University. Following confirmation of satisfactory root canal treatment. Tooth preparation will follow standardized endocrown guidelines. All preparations will be performed by a single calibrated operator (Y.A.E.). Full-arch digital impressions will be captured using an intraoral scanner, including scans of the prepared tooth, opposing arch, and bite registration. Digital files (STL format) will be used to design definitive restorations in CAD software. Following digital design, participants will be randomly allocated (1:1 ratio) to one of two fabrication groups: Group 1 (Intervention): Additive manufacturing (3D-printed resin composite) Group 2 (Comparator): Subtractive manufacturing (milled resin composite) Teeth will be temporized with intermediate restorative material, then temporary materials will be removed and preparations cleaned. Restorations will be tried to verify fit, contacts, and occlusion. After cementation, scan the seated restoration with the same intraoral scanner to create baseline restoration STL file (T0) for longitudinal fit assessment. Participants will be recalled at baseline (T0), 6 months (T1), 12 months (T2) and18 months (T3). At each visit, restorations will be evaluated using Modified FDI criteria (clinical performance) and 3D digital superimposition (Restoration fit via Geomagic Control X)
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
52
Subtractive Manufacturing, the control group will utilize restorations fabricated via subtractive manufacturing, specifically by milling from industrially fabricated blocks of nanohybrid composite. This method is the established gold standard for producing CAD/CAM resin composite restorations. It is known for creating restorations with excellent mechanical properties, high density, and predictable clinical performance due to the optimized, industrial-grade polymerization of the blocks. These materials, which include polymer-infiltrated ceramic networks (PICNs) and resin nanoceramics, were developed to combine the favorable properties of both ceramics and resin composites, offering a biomimetic alternative to traditional glass-ceramics.
Additive Manufacturing, the intervention group will feature restorations fabricated via 3D printing. This technology is more time and cost-efficient, more accurate, and could provide a considerable alternative to the currently applied CNC milling, reduced material waste, and the ability to create complex geometries with high precision. Recent studies have shown that 3D-printed restorations can achieve promising results in terms of marginal and internal fit, which are critical for clinical longevity. This has spurred the development of novel, ceramic-filled hybrid materials specifically engineered for permanent 3D-printed restorations. Manufacturers of these materials claim high dimensional stability, flexural strength, and a modulus suitable for definitive restorations (e.g., Bego; VarseoSmile Triniq technical product data sheet). However, there is a lack of clinical data to support these claims.
October city, October 6 university
Giza, Egypt
Clinical performance
World Dental Federation (FDI) criteria set to evaluate direct and indirect dental restorations: Hickel et al. (2023). Aesthetic properties of Endocrown restorations (Domain A): 1. Surface Luster 2. Staining (surface, margin) 3. color match and translucency 4. Esthetic anatomical form Functional performance of Endocrown restorations (Domain F): 5. Fracture of material and retention 6. Marginal adaptation 7. Approximal anatomical form Biological Properties of Endocrown restorations (Domain B): 8. Recurrence of caries (CAR) 9. Tooth integrity (enamel cracks, tooth fracture) 10. Periodontal response
Time frame: T0=baseline (1st week), T1=6 months, T2=12 months and T3=18 months follow-up.
Restoration Fit
1. Marginal Adaptation 2. Internal Adaptation Triple-scan digital superimposition (Geomagic Control X 2022 software)
Time frame: T0=baseline (1st week), T1=6 months, T2=12 months and T3=18 months follow-up.
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