Depth of Cure and Mechanical Properties of Bulk-Fill Posterior Dental Composites

AbstractFibre-reinforced dental composites are proven to have superior mechanical properties in comparison with micro/nano/hybrid filled composites. However, the addition of small quantities of short glass fibres could affect the dimensional stability of the restoration both during initial stages as well as through the life of the restoration. This in-vitro study aims at evaluating the physical properties of short S-Glass reinforced flowable dental composites. Two S-Glass short fibre-particulate reinforced (5 wt% of aspect ratios 50 and 70) and one particulate only reinforced flowable dental composites were prepared with UDMA-TEGDMA based dental monomer systems. Samples were photopolymersied for 60 s and stored in distilled water at 37 °C for 24 h before testing. Depth of cure (through-thickness microhardness), volumetric shrinkage (Archimedes technique), polymerisation stress (cantilever based tensometer), curing exotherm (thermocouple), water sorption and solubility (ISO 4049) and thermal expansion coefficient (dilatometer) were determined. The test results were statistically analysed using one-way ANOVA (p < 0.05). Depth of cure increased by 41%, volumetric shrinkage increased by 8.3%, shrinkage stress increased by 37.6%, exotherm increased by 20.2%, and thermal expansion reduced by 6.4% while water sorption and solubility had a negligible effect with the inclusion of short glass fibres. The study demonstrates that within the same organic resin system and quantity, a small replacement of fillers with short fibres could significantly affect the dimensional stability of the composite system. In conjunction with mechanical properties, this study could help clinicians to gain confidence in fibre reinforced dental composite restorative system.

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Influence of artificial aging: mechanical and physicochemical properties of dental composites under static and dynamic compression

Clinical Oral Investigations ◽

10.1007/s00784-021-04122-0 ◽

2021 ◽

Author(s):

D. C. Gornig ◽

R. Maletz ◽

P. Ottl ◽

M. Warkentin

Keyword(s):

Mechanical Properties ◽

Water Sorption ◽

Artificial Aging ◽

Filler Content ◽

Dynamic Compression ◽

The Other ◽

Chemical Degradation ◽

Dental Composites ◽

Compression Tests ◽

Acid Ph

Abstract Objective The aim of the study was to evaluate the influence of filler content, degradation media and time on the mechanical properties of different dental composites after in vitro aging. Materials and Methods Specimens (1 mm3) of three commercially available composites (GrandioSO®, Arabesk Top®, Arabesk Flow®) with respect to their filler content were stored in artificial aging media: artificial saliva, ethanol (60%), lactic acid (pH 5) and citric acid (pH 5). Parameters (Vickers microhardness, compressive strength, elastic modulus, water sorption and solubility) were determined in their initial state (control group, n = 3 for microhardness, n = 5 for the other parameters) and after 14, 30, 90 and 180 days (n = 3 for microhardness, n = 5 for the other parameters for each composite group, time point and media). Specimens were also characterized with dynamic-mechanical-thermal analysis (compression tests, F = ± 7 N; f = 0.5 Hz, 1 Hz and 3.3 Hz; t = 0–170 °C). Results Incorporation of fillers with more than 80 w% leads to significantly better mechanical properties under static and dynamic compression tests and a better water sorption behavior, even after chemical degradation. The influence of degradation media and time is of subordinate importance for chemical degradation. Conclusion Although the investigated composites have a similar matrix, they showed different degradation behavior. Since dentine and enamel occur only in small layer thickness, a test specimen geometry with very small dimensions is recommended for direct comparison. Moreover, the use of compression tests to determine the mechanical parameters for the development of structure-compatible and functionally adapted composites makes sense as an additional standard. Clinical relevance Preferential use of highly filled composites for occlusal fillings is recommended.

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Mechanical properties, volumetric shrinkage and depth of cure of short fiber-reinforced resin composite

Dental Materials Journal ◽

10.4012/dmj.2015-280 ◽

2016 ◽

Vol 35 (3) ◽

pp. 418-424 ◽

Cited By ~ 29

Author(s):

Akimasa TSUJIMOTO ◽

Wayne W. BARKMEIER ◽

Toshiki TAKAMIZAWA ◽

Mark A. LATTA ◽

Masashi MIYAZAKI

Keyword(s):

Mechanical Properties ◽

Resin Composite ◽

Short Fiber ◽

Volumetric Shrinkage ◽

Fiber Reinforced ◽

Depth Of Cure

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Amalgam: Reactor Response

Advances in Dental Research ◽

10.1177/08959374880020012401 ◽

1988 ◽

Vol 2 (1) ◽

pp. 83-86 ◽

Cited By ~ 2

Author(s):

E.H. Greener

Keyword(s):

Physical Chemistry ◽

Mechanical Properties ◽

Dental Composites ◽

Current Position ◽

Posterior Restorations

Although the number of research reports on dental composites far outnumbers those on amalgams in recent years, amalgam remains the popular clinical choice for posterior restorations. Recent research on corrosion phenomena, mechanical properties, and new compositions indicates that the useful properties of amalgam may still be improved. Given the current position of amalgam within the dental armamentarium, focused research on the physical chemistry and metallurgy of current and new amalgams may continue to pay dividends.

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Improved Fracture Toughness and Conversion Degree of Resin-Based Dental Composites after Modification with Liquid Rubber

Materials ◽

10.3390/ma13122704 ◽

2020 ◽

Vol 13 (12) ◽

pp. 2704

Author(s):

Krzysztof Pałka ◽

Joanna Kleczewska ◽

Emil Sasimowski ◽

Anna Belcarz ◽

Agata Przekora

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Dental Materials ◽

Degree Of Conversion ◽

Dental Composites ◽

Conversion Degree ◽

Matrix Resin ◽

Ceramic Filler ◽

Liquid Rubber ◽

The Matrix

There are many methods widely applied in the engineering of biomaterials to improve the mechanical properties of the dental composites. The aim of this study was to assess the effect of modification of dental composites with liquid rubber on their mechanical properties, degree of conversion, viscosity, and cytotoxicity. Both flow and packable composite consisted of a mixture of Bis-GMA, TEGDMA, UDMA, and EBADMA resins reinforced with 60 and 78 wt.% ceramic filler, respectively. It was demonstrated that liquid rubber addition significantly increased the fracture toughness by 9% for flow type and 8% for condensable composite. The influence of liquid rubber on flexural strength was not statistically significant. The addition of the toughening agent significantly reduced Young’s modulus by 7% and 9%, respectively, while increasing deformation at breakage. Scanning electron microscopy (SEM) observations allowed to determine the mechanisms of toughening the composites reinforced with ceramic particles. These mechanisms included bridging the crack edges, blocking the crack tip by particles and dissipation of fracture energy by deflection of the cracks on larger particles. The degree of conversion increased after modification, mainly due to a decrease in the matrix resin viscosity. It was also shown that all dental materials were nontoxic according to ISO 10993-5, indicating that modified materials have great potential for commercialization and clinical applications.

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Effects of Polymerization Mode and Interaction with Hydroxyapatite on the Rate of pH Neutralization, Mechanical Properties, and Depth of Cure in Self-Adhesive Cements

European Journal of Dentistry ◽

10.1055/s-0039-1696057 ◽

2019 ◽

Vol 13 (02) ◽

pp. 178-186

Author(s):

Fabiana S. A. S. Camargo ◽

Alejandra H. M. González ◽

Roberta C. B. Alonso ◽

Vinicius Di Hipólito ◽

Paulo H. P. D'Alpino

Keyword(s):

Mechanical Properties ◽

Infrared Spectroscopy ◽

Elastic Modulus ◽

Flexural Strength ◽

The Self ◽

Chemical Bonds ◽

Resin Cements ◽

Adhesive Resin ◽

Depth Of Cure ◽

Ph Neutralization

Abstract Objective The aim of the study was to evaluate the physicochemical properties of self-adhesive resin cements associated with hydroxyapatite (HAp) according to the polymerization activation. Materials and Methods Specimens of cements (PermaCem 2.0 [DMG]; MaxCem Elite [Kerr], and RelyX U200 [3M ESPE]) were distributed into three groups: activation mode; self-cured and dual-cured modes; and association or not with HAp powder mode. The pH neutralization was evaluated as a function of time. Flexural strength and elastic modulus were also tested (0.5 mm/min.). The depth of cure was also analyzed using the scraping test (ISO 4049). Infrared spectroscopy was also used to collect the spectra of specimens to evaluate the chemical bonds. Statistical comparisons were conducted at 5% of significance. Results The aggressiveness of the self-adhesive resin cements evaluated varied among the materials with a tendency for neutralization. Self-cure groups exhibited lower pH throughout the entire evaluation when compared with that of the dual-cure ones, irrespective of the addition of HAp. MaxCem Elite when photoactivated was the only cement influenced by the addition of the HAp in terms of mechanical properties. The self-adhesive cements tested presented equivalent depth of cure based on the ISO 4049 requirements, regardless of the evaluated factors. Conclusions Based on the parameters evaluated, the results demonstrated that most of the self-adhesive cements remained unaltered or improved when mixed with HAp, regardless of the activation mode.

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Water sorption and mechanical properties of dental composites

Biomaterials ◽

10.1016/0142-9612(90)90159-n ◽

1990 ◽

Vol 11 (3) ◽

pp. 219-223 ◽

Cited By ~ 37

Author(s):

C. Bastioli ◽

G. Romano ◽

C. Migliaresi

Keyword(s):

Mechanical Properties ◽

Water Sorption ◽

Dental Composites

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Mechanical Properties of Machinable Zirconia Dental Composites

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.1587 ◽

2007 ◽

Vol 336-338 ◽

pp. 1587-1589

Author(s):

Wen Xu Li ◽

Hua Zhao ◽

Ying Song ◽

Bin Su ◽

Fu Ping Wang

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Calcium Phosphate ◽

Flexural Strength ◽

Dental Composite ◽

The Other ◽

Dental Composites ◽

Composite Ceramics ◽

Cad Cam ◽

The Common

Ca3(PO4)2/ZrO2 dental composite ceramics using for CAD/CAM system were prepared and the effects of weak phases on microstructures and mechanical properties were studied. The results showed that intergranular spreads happened with the increasing Ca3(PO4)2 contents due to the discontinuity of weak interfaces between Zirconia and Calcium phosphate in matrix. So the flexural strength and hardness of the Ca3(PO4)2/ZrO2 composite ceramics were decreased effectively, which improved the machinability of the composites. On the other hand, strong interfaces between Zirconias increased the integrality of the ceramic structures. ZrO2 composite Ceramics with 15% Ca3(PO4)2 were sintered at 1350°C. The flexural strength is 300.44MPa, fracture toughness is 4.36 MPam1/2, and hardness is 6.69 GPa. The cutting exponent of the Ca3(PO4)2/ZrO2 composite ceramics is obviously lower than that of the common commercial Vita Mark II and Dicor MGC ceramics, which shows good mechanical properties and machinability.

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