Relationship between shade and depth of cure for light-activated dental composite resins

doi:10.1016/S0109-5641(86)80057-4

Dental Materials

Volume 2, Issue 2, April 1986, Pages 80-84

https://doi.org/10.1016/S0109-5641(86)80057-4 Get rights and content

Abstract

Depth of cure of 3 light-activated composite resins was evaluated by hardness and infrared analysis and related to the shade and translucency of the material. For one of the 3 brands, the depth of cure for the darkest shade was equivalent to that of the lightest shade, suggesting that depth of cure of light-activated composite resins may be less dependent upon shade than upon translucency.

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There are more references available in the full text version of this article.

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This study aimed to modify an experimental dental composite using a synthesized nano-structured methacrylated zirconium-based MOF to enhance physical/mechanical properties.
The previously known Uio-66-NH₂ MOF was first synthesized and post-modified with Glycidyl Methacrylate (GMA). Fourier Transform Infrared (FTIR) Spectroscopy and CHNS analysis confirmed the post-modification reaction. The prepared filler was investigated by XRD, BET, SEM-EDS, and TEM. The experimental composite was prepared by mixing 60% wt. of resin matrix with 40% wt. of fillers, including silanized silica (SS) or Uio-66-NH-Me (UM). The experimental composites' depth of cure (DPC) was investigated in five groups (G1 =40% SS, G2 =30%SS+10%UM, G3 =20%SS+20%UM, G4 =10%SS+30%UM, G5 =40%UM). Then flexural strength(FS), Elastic Modulus(EM), solubility(S), water sorption(WS), degree of conversion(DC), polymerization shrinkage(PS), and polymerization stress(PSR) of the groups with DPC of more than 1 mm were investigated. Finally, the cytotoxicity of composites was studied.
The groups with more than 20% wt. UM, filler (G4, G5) had lesser than 1 mm DPC. Therefore, we investigated three groups' physical and mechanical properties with lower than 20% UM filler (G1-G3). Within these groups, G3 has a higher FS, EM (P < 0.05), and lower WS and S (P < 0.05). DC dropped in G2 and G3 compared to G1 (p < 0.05), but there was no significant difference between G2 and G3 (P = 0.594).
This new filler is an innovative coupling-agent free filler and can be part of dental filler technology itself. It can also introduce a new group of dental fillers based on MOFs, but it still needs a complete investigation to be widely used.
Compositional boundaries for functional dental composites containing calcium orthophosphate particles
2023, Journal of the Mechanical Behavior of Biomedical Materials
To investigate the interrelationships among handling, degree of conversion (DC), mechanical behavior and Ca²⁺ release of composites containing dicalcium phosphate dihydrate (DCPD, CaHPO₄.2H₂O), as a function of total inorganic content and DCPD: glass ratio.
Twenty-one formulations (1 BisGMA: 1 TEGDMA, in mols) with inorganic fractions ranging from zero to 50 vol% and different DCPD: glass ratios were evaluated for viscosity (parallel plate rheometer, n = 3), DC (near-FTIR spectroscopy, n = 3), fracture toughness/K_1C (single-edge notched beam, n = 7–11) and 14-day Ca²⁺ release (inductively coupled plasma optical emission spectroscopy, n = 3). Data were analyzed by ANOVA/Tukey test (except viscosity, where Kruskal-Wallis/Dunn tests were used, α: 0.05).
Viscosity and DC increased with DCPD: glass ratio among composites with the same inorganic content (p < 0.001). At inorganic fractions of 40 vol% and 50 vol%, keeping DCPD content at a maximum of 30 vol% did not compromise K_1C. Ca²⁺ release showed an exponential relationship with DCPD mass fraction in the formulation (R² = 0.986). After 14 days, a maximum of 3.8% of the Ca²⁺ mass in the specimen was released.
Formulations containing 30 vol% DCPD and 10–20 vol% glass represent the best compromise between viscosity, K_1C and Ca²⁺ release. Materials with 40 vol% DCPD should not be disregarded, bearing in mind that Ca²⁺ release will be maximized at the expense of K_1C.
Misinterpretation of ISO 4049 standard recommendations: Impact on Young's modulus and conversion degree of dental composites
2020, Journal of the Mechanical Behavior of Biomedical Materials
The purpose of this study was to study the effects on Young's modulus and conversion degree of variations in polymerization conditions during the 3-point bending test of composite samples in accordance with the ISO 4049 standard.
Three nanocomposites were used in the 3-point bending test based on the conditions described in the ISO 4049 standard. Samples of 2 mm × 2 mm x 25 mm were fabricated and tested with a different number of irradiation points and irradiation time. Conversion degree of the samples were also measured by micro-Raman spectroscopy and correlated with the Young's modulus values obtained for each one.
The variations in curing protocol during specimen's realization influenced the Young's modulus and degree of conversion of all composites. These two properties correlated well. The ISO 4049 standard defines the conditions for performing the properties tests of composites to allow reproducibility and comparison of different studies. Concerning the 3-point bending test, even a minimal change in the state causes differences in the results obtained. The standard should thus clarify the tools that can be used when producing samples in order to minimize discrepancies.
The influence of the parameters surrounding the design of the samples should be controlled and defined so as not to include bias in the studies carried out. This will allow literature studies to be compared with more accuracy.
Radiation crosslinking of pigmented coating material by UV LEDs enabling depth curing and preventing oxygen inhibition
2020, Progress in Organic Coatings
LED light sources emit in a small wavelength region, e.g. in the blue light and UV-A. These LEDs can be applied for the radiation curing via radical polymerization, which is a growing sector in the coating industry. LEDs will in prospect substitute mercury arc lamps as the light sources, but development of higher intense LEDs and also in the UV-B or UV-C range is still in progress. In this report the efficiency of initiator systems was analyzed for the photopolymerization of UDMA. The chosen systems are usually used in the coating industry and others were invented in the dentistry and holography. The aim is the depth curing of urethane dimethacrylate (UDMA) with the help of UV LEDs at 365 nm, 395 nm, and 405 nm. The overlap of the absorbance of the initiator systems and the emission of the LED is discussed regarding the reactivity in the top layer and a thickness up to 20 mm hereby giving insights in the influence of the light source and the reactivity or spectral properties of the initiator system on the photopolymerization process. Surprisingly, the initiator systems like Ivocerin, and HABI-mercapto, which are unusual as initiators for the curing of coatings, show a high efficiency. Even pigmented and filled systems are curable up to a depth of 4–20 mm, respectively. Furthermore, applying a UV-C LED at 278 nm and using these initiators also decrease the tackiness on the surface caused by oxygen inhibition.
Effect of calcium orthophosphate: Reinforcing glass ratio and prolonged water storage on flexural properties of remineralizing composites
2020, Journal of the Mechanical Behavior of Biomedical Materials
To compare the effects of replacing reinforcing barium glass particles by DCPD (dicalcium phosphate dihydrate), as opposed to simply reducing glass filler content, on composite flexural properties and degree of conversion (DC). On a second set of experiments, composites with different “DCPD: glass” ratios were exposed to prolonged water immersion to verify if the presence of DCPD particles increased hydrolytic degradation. Methods: Two series of composites were prepared: 1) composites with total inorganic content of 50 vol% and “DCPD: glass” ratios ranging from zero (glass only) to 1.0 (DCPD only), in 0.25 increments, and 2) composites containing only silanized glass (from zero to 50 vol%). Disk-shaped specimens were fractured under biaxial flexural loading after 24 h in water. Another set of specimens of composites with different “DCPD: glass” ratios was stored in water for 24 h, 30, 60, 90 and 120 days and tested in flexure. DC was determined using FTIR spectroscopy. Data were analyzed using Kruskal-Wallis/Dunn test (flexural properties) or ANOVA/Tukey test (DC, alpha: 0.05). Results: For glass-only composites, reducing inorganic content caused a linear decrease in strength. The presence of DCPD did not affect composite strength up until a “DCPD: glass” ratio of 0.5. On the other hand, materials with 0.75 and 1.0 DCPD showed significantly lower strength than the glass-only composite with 12.5 vol% filler and the unfilled resin, respectively (p < 0.001). Except for the 0.25 DCPD composite, the presence of DCPD did not contribute to increase flexural modulus. After water storage, composites containing DCPD showed higher percent reductions in properties than the control, but only in a few cases the effect was statistically significant (strength: 0.5 DCPD, modulus: 0.25 and 1.0 DCPD). DC was only marginally affected by DCPD fraction. Significance: For composites with “DCPD: glass” of 0.25 and 0.5, reductions in strength were related to the lower glass content, and not due to the presence of DCPD. Flexural modulus was primarily defined by glass content. Overall, composites containing DCPD particles presented higher reductions in properties after water storage, but it remained within limits reported for commercial materials.
Factors affecting polymerization of resin-based composites: A literature review
2017, Saudi Dental Journal
Citation Excerpt :
For darker shades in RBCs, some manufacturers have recommended increasing the light curing time. This recommendation is evidenced and supported by several studies reporting an effect of the RBC shade on the degree of monomer convergence (Ferracane et al., 1986; Guiraldo et al., 2009; Shortall, 2005). In 2009, Guiraldo et al. conducted an in vitro study of the effect of different Flitek Z250 RBC shades (A1, A2, A3, A3.5 and A4 vita shade guide) on the DC.
The aim of this review was to help clinicians improve their understanding of the polymerization process for resin-based composites (RBC), the effects of different factors on the process and the way in which, when controlled, the process leads to adequately cured RBC restorations.
Ten factors and their possible effects on RBC polymerization are reviewed and discussed, with some recommendations to improve that process. These factors include RBC shades, their light curing duration, increment thickness, light unit system used, cavity diameter, cavity location, light curing tip distance from the curing RBC surface, substrate through which the light is cured, filler type, and resin/oral cavity temperature.
The results of the review will guide clinicians toward the best means of providing their patients with successfully cured RBC restorations.

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^*: Dr. Jack Ferracane, Department of Dental Materials, Baylor College of Dentistry, 3302 Gaston Ave., Dallas, TX 75246, USA.

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Dental Materials

Abstract

References (10)

Visible light-activated resins-depth of cure

J Am Dent Assoc

In vitro depth of cure of photoactivated composites

J Dent Res

Post-irradiation polymerization of visible light-activated composite resin

J Dent Res

Cure of resin-based restorative materials. II. White light photopolymerized resins

Aust Dent J

Conversion in different depths of ultraviolet and visible light-activated composite materials

Acta Odontol Scand

Cited by (95)

Evaluation of physical/mechanical properties of an experimental dental composite modified with a zirconium-based metal-organic framework (MOF) as an innovative dental filler

Compositional boundaries for functional dental composites containing calcium orthophosphate particles

Misinterpretation of ISO 4049 standard recommendations: Impact on Young's modulus and conversion degree of dental composites

Radiation crosslinking of pigmented coating material by UV LEDs enabling depth curing and preventing oxygen inhibition

Effect of calcium orthophosphate: Reinforcing glass ratio and prolonged water storage on flexural properties of remineralizing composites

Factors affecting polymerization of resin-based composites: A literature review

Original articleRelationship between shade and depth of cure for light-activated dental composite resins

Abstract

J Am Dent Assoc

In vitro depth of cure of photoactivated composites

J Dent Res

Post-irradiation polymerization of visible light-activated composite resin

J Dent Res

Cure of resin-based restorative materials. II. White light photopolymerized resins

Aust Dent J

Conversion in different depths of ultraviolet and visible light-activated composite materials

Acta Odontol Scand

Original article
Relationship between shade and depth of cure for light-activated dental composite resins