Skip to content
6CCVD Research

Translucency of CAD/CAM and 3D Printable Composite Materials for Permanent Dental Restorations

At a Glance

Section titled “At a Glance”
MetadataDetails
Publication Date2023-03-15
JournalPolymers
AuthorsAlessandro Vichi, Dario Balestra, Nicola Scotti, Chris Louca, Gaetano Paolone
InstitutionsIstituto di Ricovero e Cura a Carattere Scientifico San Raffaele, Vita-Salute San Raffaele University
Citations54
AnalysisFull AI Review Included

Executive Summary

Section titled “Executive Summary”

This study investigated the optical translucency of eight composite materials (seven CAD/CAM blocks and one 3D printable resin) used for permanent fixed dental prostheses (FDPs), focusing on metrics critical for aesthetic engineering: Contrast Ratio (CR), Translucency Parameter (TP), and TP00.

  • Significant Variability: The tested materials exhibited a wide range of translucency values, with CR ranging from 59.0 (most translucent) to 84.4 (most opaque), and TP ranging from 8.96 to 15.75.
  • Most Translucent Material: Cerasmart High Translucency (CS HT) demonstrated the highest translucency (CR = 59.0 ± 1.1; TP = 15.75 ± 0.53), statistically significantly more translucent than all other materials tested.
  • Most Opaque Material: Katana Avencia Opaque (KAT OP) showed the lowest translucency (CR = 84.4 ± 0.6; TP = 8.96 ± 0.23), confirming its suitability for substrate masking.
  • Translucency Level Inconsistency: The null hypothesis was accepted: manufacturer-designated translucency levels (e.g., High Translucency, HT) do not correspond across different materials. For instance, Cerasmart Low Translucency (CS LT) was more translucent (CR = 64.8) than Brilliant Crios High Translucency (BC HT) (CR = 66.1).
  • 3D Printed Resin Performance: The Permanent Crown Resin (PCR) showed intermediate translucency (CR = 71.06), correlating with its lower filler load (30-50% wt.) compared to the CAD/CAM blocks (61-86% wt.).
  • Engineering Implication: Material selection for FDPs requires careful consideration of measured optical properties, as reliance solely on manufacturer HT/LT labels may lead to clinical failure in masking discolored substrates or achieving biomimetic aesthetics.

Technical Specifications

Section titled “Technical Specifications”
ParameterValueUnitContext
Specimen Thickness1.0mmStandardized thickness for all tests
Specimen Dimensions14 x 14mmSquare cross-section
CR Range (Overall)59.0 to 84.4N/AContrast Ratio (Opacity Estimate)
TP Range (Overall)8.96 to 15.75N/ATranslucency Parameter (CIELab*)
TP00 Range (Overall)6.31 to 12.47N/ATranslucency Parameter (CIEDE2000)
Most Translucent Material (CR)59.0 ± 1.1N/ACerasmart (CS HT)
Most Opaque Material (CR)84.4 ± 0.6N/AKatana Avencia (KAT OP)
3D Printing Layer Thickness50”mPermanent Crown Resin (PCR) fabrication
PCR Filler Content30-50% wt.Methacrylic acid ester-based resin
CAD/CAM Filler Content Range61-86% wt.Resin nano-ceramics/hybrid blocks
Spectrophotometer IlluminantD65N/AStandard measurement condition
Standard Observer10°Standard measurement condition

Key Methodologies

Section titled “Key Methodologies”

The study employed precise subtractive and additive manufacturing techniques followed by standardized optical measurements:

  1. CAD/CAM Specimen Preparation: Commercial blocks were cut into 1.0 mm thick, 14 mm x 14 mm specimens (n=10 per material/translucency level) using a water-cooled low-speed diamond saw to ensure dimensional accuracy.
  2. 3D Printing Specimen Preparation: Specimens were designed (Thinkercad), exported (STL), and printed (Formlabs 3B) using Permanent Crown Resin (PCR) at a 50 ”m layer thickness.
  3. Post-Curing and Cleaning: 3D printed specimens underwent automated washing (3 min in 99% IPA) followed by two curing cycles (20 min at 60 °C each) in a FormCure unit.
  4. Surface Finishing: All specimens were finished and polished using wet 320- and 600-grit silicone-carbide paper, followed by ultrasonic cleaning in distilled water. 3D printed specimens were also sandblasted (50 ”m glass beads, 1.5 bar) between curing steps to remove layered filler particles.
  5. Optical Measurement Protocol: Translucency was measured using a benchtop spectrophotometer (OceanOptics PSD1000) equipped with an integrating sphere, utilizing white and black standard tiles as references.
  6. Data Analysis: CR (Contrast Ratio), TP (CIELab* color difference over black/white), and TP00 (CIEDE2000 color difference over black/white) were calculated. Statistical analysis involved One-Way ANOVA followed by Tukey post hoc tests (p < 0.05).

Commercial Applications

Section titled “Commercial Applications”

The findings are directly relevant to the engineering and clinical application of aesthetic restorative materials in dentistry, focusing on material optimization and selection criteria.

  • Aesthetic Dental Restorations: Manufacturing of high-performance, aesthetic fixed dental prostheses (FDPs), including crowns, veneers, inlays, and onlays, using both subtractive (CAD/CAM) and additive (3D Printing) methods.
  • Biomimetic Material Development: Guiding the formulation of next-generation resin nano-ceramics by correlating filler content (size, refractive index) and polymer matrix composition (e.g., Bis-GMA vs. Bis-EMA) with target optical properties (TP, CR) to match natural enamel (TP ~15-19) and dentin (CR ~0.65).
  • Substrate Masking Solutions: Selecting highly opaque materials (high CR, low TP, e.g., KAT OP) for restorations requiring effective masking of discolored dentin or metallic substructures, ensuring clinical longevity and aesthetic success.
  • 3D Printing Material Optimization: Informing the development of 3D printable resins for permanent use by establishing performance benchmarks against established CAD/CAM blocks, particularly regarding the necessary balance between low viscosity monomers (like Bis-EMA) and high filler loads for improved mechanical and optical properties.
  • Cementation Protocol Engineering: Data on material translucency and thickness (1.0 mm tested) are crucial for selecting appropriate luting cements (e.g., dual-cure vs. light-cure) to ensure adequate light transmission for polymerization beneath the restoration.
View Original Abstract

The aim of the study was to compare the translucency of CAD/CAM and printable composite materials for fixed dental prostheses (FDP). Eight A3 composite materials (7 CAD/CAM and 1 printable) for FPD were used to prepare a total of 150 specimens. CAD/CAM materials, all characterized by two different opacity levels, were: Tetric CAD (TEC) HT/MT; Shofu Block HC (SB) HT/LT; Cerasmart (CS) HT/LT; Brilliant Crios (BC) HT/LT; Grandio Bloc (GB) HT/LT; Lava Ultimate (LU) HT/LT, Katana Avencia (KAT) LT/OP. The printable system was Permanent Crown Resin. 1.0 mm-thick specimens were cut from commercial CAD/CAM blocks using a water-cooled diamond saw, or 3D printed. Measurements were performed using a benchtop spectrophotometer with an integrating sphere. Contrast Ratio (CR), Translucency Parameter (TP), and Translucency Parameter 00 (TP00) were calculated. One Way ANOVA followed by Tukey test for post hoc were performed for each of the translucency system. The tested materials exhibited a wide range of translucency values. CR ranged from 59 to 84, TP from 15.75 to 8.96, TP00 from 12.47 to 6.31. KAT(OP) and CS(HT) showed, respectively, the lowest and highest translucency for CR, TP and TP00. Due to the significant range of reported translucency values, clinicians should exercise caution when choosing the most appropriate material, especially considering factors such as substrate masking, and the necessary clinical thickness.

Tech Support

Section titled “Tech Support”

Original Source

Section titled “Original Source”

References

Section titled “References”
  1. 2021 - A Potential Application of Materials Based on a Polymer and CAD/CAM Composite Resins in Prosthetic Dentistry [Crossref]
  2. 2018 - CAD/CAM Ceramic Restorative Materials for Natural Teeth [Crossref]
  3. 2014 - Resin-Composite Blocks for Dental CAD/CAM Applications [Crossref]
  4. 2020 - Flexural Resistance of CAD-CAM Blocks. Part 3: Polymer-Based Restorative Materials for Permanent Restorations
  5. 2018 - Effect of Staining Beverages on Color and Translucency of CAD/CAM Composites [Crossref]
  6. 1981 - Optical Properties of Direct Restorative Materials [Crossref]
  7. 2014 - Review of Translucency Determinations and Applications to Dental Materials [Crossref]

Reads Similar to This

Analysis of the depth of penetration of an epoxy resin-based sealer following a final rinse of irrigants and use of activation systems - An in vitro study Assessment of microtensile bond strength of silver diamine fluoride with potassium iodide–treated carious primary dentin restored with glass ionomer cement and/or composite - In vitro study Higher-order resonance of single-crystal diamond cantilever sensors toward high f‧Q products