Influence of Light-curing Mode on the Mechanical Properties of Dental Resin Nanocomposites

Various amounts of methacryl polyhedral oligomeric silsesquioxane (POSS) were explored to be incorporated into novel nano SiO2 dental resin composites using light curing method. The scanning electron microscopy (SEM), optical microscopy, fourier transform infrared spectroscopy (FTIR), nanoindentation, nanoscratch and three-point flexure tests were performed. The volumetric shrinkage and mechanical properties such as hardness, elastic modulus, resistance, flexural strength and fracture energy were analyzed. With the additions of POSS, the volume shrinkage decreased and the mechanical properties initially increased. The effects of POSS on these properties were studied to provide a reference for clinically selecting a composite resin with excellent properties.

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Comparative Effect of Self- or Dual-Curing on Polymerization Kinetics and Mechanical Properties in a Novel, Dental-Resin-Based Composite with Alkaline Filler

Materials ◽

10.3390/ma11010108 ◽

2018 ◽

Vol 11 (1) ◽

pp. 108 ◽

Cited By ~ 12

Author(s):

Nicoleta Ilie

Keyword(s):

Mechanical Properties ◽

Flexural Strength ◽

Mechanical Stability ◽

Polymerization Kinetics ◽

Dental Resin ◽

Polymerization Kinetic ◽

Double Bond Conversion ◽

Light Curing ◽

Dual Curing ◽

The Impact

Dental bulk-fill restorations with resin-composites (RBC) are increasing in popularity, but doubts concerning insufficient curing in depth still disconcert clinicians. An alternative might be offered by modern dual-cured RBCs, which additionally provide bioactive properties. This study assessed the impact of additional light-curing on polymerization kinetics, the degree of conversion (DC) and mechanical properties of a novel, dual-cured RBC with alkaline fillers. Since the bioactivity of a material often implies a release of compounds, the mechanical stability in simulated clinical environments was also evaluated. Polymerization kinetics and DC were assessed at 2- and 4-mm specimen depths in real-time up to one hour (n = 6). Incident and transmitted irradiance and radiant exposure were recorded at 2- and 4-mm depths. Micro-mechanical profiles (n = 6) were assessed in 100-µm steps along 6-mm deep specimens at 24 h post-polymerization. Flexural strength and modulus (n = 10) were determined up to three months of immersion in neutral (6.8) and acidic (4) pH conditions. DC variation in time was best described by a sigmoidal function (R2 > 0.98), revealing a retarded (3.4 ± 0.4 min) initiation in C=C double bond conversion in self-cured versus dual-cured specimens. The setting reaction kinetic was identical at 2- and 4-mm depths for the self-cure mode. For the dual-cure mode, polymerization initiated at 2-mm depth instantly with light-irradiation, while being retarded (0.8 min) at 4-mm depth. The material behaves similarly, irrespective of curing mode or depth, later than 11 min after mixing. Flexural strength and modulus was comparable to regular RBCs and maintained up to three months in both neutral and acidic conditions. Additional light-curing initially accelerates the polymerization kinetic and might help shorten the restauration procedure by hardening the material on demand, however with no effect on the final properties.

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Effect of Accelerated Aging on Some Mechanical Properties and Wear of Different Commercial Dental Resin Composites

Materials ◽

10.3390/ma14112769 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2769

Author(s):

Jonne Oja ◽

Lippo Lassila ◽

Pekka K. Vallittu ◽

Sufyan Garoushi

Keyword(s):

Mechanical Properties ◽

Flexural Strength ◽

Accelerated Aging ◽

Wear Depth ◽

Resin Composites ◽

Expiration Date ◽

Dental Resin ◽

Hydrothermal Aging ◽

Dental Resin Composites

The aim of current in vitro research was to determine the effect of hydrothermal accelerated aging on the mechanical properties and wear of different commercial dental resin composites (RCs). In addition, the effect of expiration date of the composite prior its use was also evaluated. Five commercially available RCs were studied: Conventional RCs (Filtek Supreme XTE, G-aenial Posterior, Denfil, and >3y expired Supreme XTE), bulk-fill RC (Filtek Bulk Fill), and short fiber-reinforced RC (everX Posterior). Three-point flexural test was used for determination of ultimate flexural strength (n = 8). A vickers indenter was used for testing surface microhardness. A wear test was conducted with 15,000 chewing cycles using a dual-axis chewing simulator. Wear pattern was analyzed by a three-dimensional (3D) noncontact optical profilometer. Degree of C=C bond conversion of monomers was determined by FTIR-spectrometry. The specimens were either dry stored for 48 h (37 °C) or boiled (100 °C) for 16 h before testing. Scanning electron microscopy (SEM) was used to evaluate the microstructure of each material. Data were analyzed using ANOVA (p = 0.05). Hydrothermal aging had no significant effects on the surface wear and microhardness of tested RCs (p > 0.05). While flexural strength significantly decreased after aging (p < 0.05), except for G-aenial Posterior, which showed no differences. The lowest average wear depth was found for Filtek Bulk Fill (29 µm) (p < 0.05), while everX Posterior and Denfil showed the highest wear depth values (40, 39 µm) in both conditions. Passing the expiration date for 40 months did not affect the flexural strength and wear of tested RC. SEM demonstrated a significant number of small pits on Denfil’s surface after aging. It was concluded that the effect of accelerated aging may have caused certain weakening of the RC of some brands, whereas no effect was found with one brand of RC. Thus, the accelerated aging appeared to be more dependent on material and tested material property.

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The Photoinitiators Used in Resin Based Dental Composite—A Review and Future Perspectives

Polymers ◽

10.3390/polym13030470 ◽

2021 ◽

Vol 13 (3) ◽

pp. 470

Author(s):

Andrea Kowalska ◽

Jerzy Sokolowski ◽

Kinga Bociong

Keyword(s):

Current Knowledge ◽

Biomechanical Properties ◽

Degree Of Conversion ◽

Dental Composite ◽

Polymerization Process ◽

Dental Composites ◽

Dental Resin ◽

Dental Resins ◽

Light Curing

The presented paper concerns current knowledge of commercial and alternative photoinitiator systems used in dentistry. It discusses alternative and commercial photoinitiators and focuses on mechanisms of polymerization process, in vitro measurement methods and factors influencing the degree of conversion and hardness of dental resins. PubMed, Academia.edu, Google Scholar, Elsevier, ResearchGate and Mendeley, analysis from 1985 to 2020 were searched electronically with appropriate keywords. Over 60 articles were chosen based on relevance to this review. Dental light-cured composites are the most common filling used in dentistry, but every photoinitiator system requires proper light-curing system with suitable spectrum of light. Alternation of photoinitiator might cause changing the values of biomechanical properties such as: degree of conversion, hardness, biocompatibility. This review contains comparison of biomechanical properties of dental composites including different photosensitizers among other: camphorquinone, phenanthrenequinone, benzophenone and 1-phenyl-1,2 propanedione, trimethylbenzoyl-diphenylphosphine oxide, benzoyl peroxide. The major aim of this article was to point out alternative photoinitiators which would compensate the disadvantages of camphorquinone such as: yellow staining or poor biocompatibility and also would have mechanical properties as satisfactory as camphorquinone. Research showed there is not an adequate photoinitiator which can be as sufficient as camphorquinone (CQ), but alternative photosensitizers like: benzoyl germanium or novel acylphosphine oxide photoinitiators used synergistically with CQ are able to improve aesthetic properties and degree of conversion of dental resin.

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Evaluating antibacterial and surface mechanical properties of chitosan modified dental resin composites

Technology and Health Care ◽

10.3233/thc-181568 ◽

2020 ◽

Vol 28 (2) ◽

pp. 165-173 ◽

Cited By ~ 5

Author(s):

Shahid Ali ◽

Laila Sangi ◽

Naresh Kumar ◽

Bharat Kumar ◽

Zohaib Khurshid ◽

...

Keyword(s):

Mechanical Properties ◽

Resin Composites ◽

Dental Resin ◽

Dental Resin Composites

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Ca-Doped mesoporous SiO2/dental resin composites with enhanced mechanical properties, bioactivity and antibacterial properties

Journal of Materials Chemistry B ◽

10.1039/c7tb02864d ◽

2018 ◽

Vol 6 (3) ◽

pp. 477-486 ◽

Cited By ~ 9

Author(s):

Yu Zhang ◽

Cui Huang ◽

Jiang Chang

Keyword(s):

Mechanical Properties ◽

Antibacterial Activity ◽

Antibacterial Properties ◽

Resin Composites ◽

Dental Resin ◽

Dental Resin Composites ◽

Mesoporous Sio2

MCS containing resin composites possess enhanced mechanical properties and antibacterial activity, and can smartly induce the deposition of apatite minerals.

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