-
Influence of inorganic nanoparticles on dental materials' mechanical properties. A narrative review.BMC Oral Health Nov 2023Inorganic nanoparticles have been widely incorporated in conventional dental materials to help in improving their properties. The literature has shown that incorporating... (Review)
Review
Inorganic nanoparticles have been widely incorporated in conventional dental materials to help in improving their properties. The literature has shown that incorporating nanoparticles in dental materials in different specialties could have a positive effect on reinforcing the mechanical properties of those materials; however, there was no consensus on the effectiveness of using nanoparticles in enhancing the mechanical properties of dental materials, due to the variety of the properties of nanoparticles itself and their effect on the mechanical properties. This article attempted to analytically review all the studies that assessed the effect of different types of inorganic nanoparticles on the most commonly used dental materials in dental specialties such as polymethyl methacrylate, glass ionomer cement, resin composite, resin adhesive, orthodontic adhesive, and endodontic sealer. The results had shown that those inorganic nanoparticles demonstrated positive potential in improving those mechanical properties in most of the dental materials studied. That potential was attributed to the ultra-small sizes and unique physical and chemical qualities that those inorganic nanoparticles possess, together with the significant surface area to volume ratio. It was concluded from this comprehensive analysis that while a definitive recommendation cannot be provided due to the variety of nanoparticle types, shapes, and incorporated dental material, the consensus suggests using nanoparticles in low concentrations less than 1% by weight along with a silane coupling agent to minimize agglomeration issues and benefit from their properties.
Topics: Humans; Dental Cements; Dental Bonding; Resin Cements; Composite Resins; Glass Ionomer Cements; Nanoparticles; Materials Testing; Surface Properties; Stress, Mechanical; Dental Materials
PubMed: 37990196
DOI: 10.1186/s12903-023-03652-1 -
International Journal of Molecular... Dec 2023The dental material industry is rapidly developing resin-based composites (RBCs), which find widespread use in a variety of clinical settings. As such, their... (Review)
Review
The dental material industry is rapidly developing resin-based composites (RBCs), which find widespread use in a variety of clinical settings. As such, their biocompatibility has gained increasing interest. This literature review presents a summary of research into the cytotoxicity of methacrylate-based composites published from 2017 to 2023. Subject to analysis were 14 in vitro studies on human and murine cell lines. Cytotoxicity in the included studies was measured via MTT assay, LDH assay, and WST-1 assay. The QUIN Risk of Bias Tool was performed to validate the included studies. Included studies (based entirely on the results of in vitro studies) provide evidence of dose- and time-dependent cytotoxicity of dental resin-based composites. Oxidative stress and the depletion of cellular glutathione (GSH) were suggested as reasons for cytotoxicity. Induction of apoptosis by RBCs was indicated. While composites remain the golden standard of dental restorative materials, their potential cytotoxicity cannot be ignored due to direct long-term exposure. Further in vitro investigations and clinical trials are required to understand the molecular mechanism of cytotoxicity and produce novel materials with improved safety profiles.
Topics: Humans; Animals; Mice; Apoptosis; Biological Assay; Cell Line; Dental Materials; Glutathione
PubMed: 38203323
DOI: 10.3390/ijms25010152 -
Dental Materials : Official Publication... Feb 2022To investigate the impact of crown geometry, crown/abutment/antagonist material and thermal loading on the two-body wear of dental materials caused by chewing simulation.
OBJECTIVES
To investigate the impact of crown geometry, crown/abutment/antagonist material and thermal loading on the two-body wear of dental materials caused by chewing simulation.
MATERIALS AND METHODS
For the crown geometry, crowns (polymethylmethacrylate (PMMA), polyetheretherketone (PEEK) and silicate ceramic (SiO)) were milled with a flat, steep, or medium cusp inclination (CINC). For the crown/abutment material, crowns (PMMA, PEEK and SiO) were combined with PMMA, polymer-infiltrated-ceramic-network (PICN), cobalt-chrome alloy (CoCr) and natural teeth (ENAM) abutments. For the antagonist material, antagonists were fabricated from PICN, CAD/CAM resin composite (RECO), steatite (STEA), steel (STL) and ENAM and tested against flat specimens (substrates) made of veneering ceramic (VC). For thermal loading, the duration (30 s, 60 s, 120 s) and presence of temperature changes (37 °C versus 5 °C/55 °C) was varied. Material losses were determined by matching scanned specimens before and after aging (400,000 chewing cycles, 50 N, 1.3 Hz). Martens parameters were determined for the antagonists/substrates. Data were analyzed using Kolmogorov-Smirnov-test, Kruskal-Wallis H, Scheffé-Post-Hoc-tests, pairwise comparisons, Bonferroni correction, one-way ANOVA, Mann-Whitney-U and Spearman rho.
RESULTS
PMMA crowns presented the highest and PEEK the lowest material losses. Flat CINC showed the lowest material losses for PEEK and SiO crowns. CoCr and ENAM abutments presented material losses in the same range. Antagonist and cumulative material losses for RECO and ENAM were similar. Thermal loading did not influence material losses.
SIGNIFICANCE
Crown geometry influences the crown and antagonists wear, with an increased cusp inclination entailing increased wear. For in vitro set-ups, CoCr abutments and RECO antagonists present valid alternatives to natural teeth. For polymers, in vitro chewing simulations may be performed at a constant temperature (37 °C).
Topics: Computer-Aided Design; Crowns; Dental Materials; Dental Porcelain; Dental Stress Analysis; Materials Testing; Silicon Dioxide
PubMed: 34953628
DOI: 10.1016/j.dental.2021.12.009 -
Nigerian Journal of Clinical Practice Oct 2021Composite resins are among the most popular restorative dental materials because of the strength and esthetic properties. The goal of this study was to assess the effect...
BACKGROUND AND AIMS
Composite resins are among the most popular restorative dental materials because of the strength and esthetic properties. The goal of this study was to assess the effect of commonly consumed beverages on microhardness and color stability of microhybrid (MH) and nanofilled NF) composite resins.
MATERIAL AND METHODS
240 samples were prepared from the composite material [MH = 120 (material I) and NF = 120 (material II)] and allocated into eight groups of 30 samples. In each group, half of the samples were tested for microhardness and another-half for color stability. After baseline measurements, the samples were immersed in test media, that is, distilled water and beverages (tea, cola, and coffee) for 15 days. Microhardness and color stability measurements were carried out after 15 days to assess the effect of beverages. The color stability and microhardness values were compared and evaluated by analysis of variance (ANOVA) using Tukey's alteration test.
RESULTS
It was reported that the microhardness decreased for both the materials after immersion in all the beverages. Percentage change in microhardness was considerably higher in material II in comparison to the material I in cola drink. Color change was significantly higher in material II compared to material I in water and coffee. Cola drink caused the maximum change in microhardness among all the beverages and coffee caused the maximum color change among all the beverages.
CONCLUSION
Both composite materials (I and II) showed a reduction in microhardness and change in color after immersion in a different type of test media.
Topics: Color; Composite Resins; Dental Materials; Humans; Materials Testing; Surface Properties; Tea
PubMed: 34657016
DOI: 10.4103/njcp.njcp_632_20 -
Advances in Clinical and Experimental... Apr 2018More than 35 substances released from composite fillings have been identified. Among these, basic monomers and the so-called co-monomers are most often reported. The...
BACKGROUND
More than 35 substances released from composite fillings have been identified. Among these, basic monomers and the so-called co-monomers are most often reported. The substances released from polymer-based materials demonstrate allergenic, cytotoxic, genotoxic, mutagenic, embryotoxic, teratogenic, and estrogenic properties.
OBJECTIVES
The aim of this study was to measure the amounts of triethylene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA) monomers released from composite dental fillings to citrate-phosphate buffer with the pH of 4, 6, 8 after 24 h and 6 months from the polymerization.
MATERIAL AND METHODS
Ten samples for each polymerization method had been made from the composite material (Filtek Supreme XT, 3M ESPE, St. Paul, USA), which underwent polymerization using the following lamps: halogen lamp (Translux CL, Heraeus Kulzer, Hanau, Germany) (sample H) and diode lamp (Elipar Freelight 2, 3M ESPE), with soft start function (group DS) and without that function (group DWS).
RESULTS
It has been demonstrated that the type of light-curing units has a significant impact on the amount of TEGDMA and UDMA released. The amount of UDMA and TEGDMA monomers released from composite fillings differed significantly depending on the source of polymerization applied, as well as the pH of the solution and sample storage time.
CONCLUSIONS
Elution of the monomers from composite material polymerized using halogen lamp was significantly greater as compared to curing with diode lamps.
Topics: Bisphenol A-Glycidyl Methacrylate; Composite Resins; Dental Materials; Halogens; Humans; Materials Testing; Methacrylates; Polyethylene Glycols; Polymerization; Polymethacrylic Acids; Polyurethanes
PubMed: 29558043
DOI: 10.17219/acem/68382 -
European Journal of Oral Sciences Apr 2022The present study reports on the long-term drug release and mechanical properties of bioactive dental filling materials based on chlorhexidine diacetate (CHX) or...
The present study reports on the long-term drug release and mechanical properties of bioactive dental filling materials based on chlorhexidine diacetate (CHX) or octinidine (di)hydrochloride (ODH) incorporated in a composite based on dimethacrylates or an ormocer. CHX or ODH were added to a nano-hybrid ormocer (O) and a nano-hybrid composite (C) with the amount of 2 wt% to achieve four matrix-drug combinations: O-CHX, O-ODH, C-CHX, and C-ODH. Drug extraction and release were measured using high-performance liquid chromatography with diode-array detection (HPLC-DAD), while drug distribution was assessed by using energy dispersive X-ray spectroscopy (EDX). Drug release in water at 37°C was observed over 87 d. To determine the material properties, the water absorption, water solubility, flexural strength and hardness were measured and compared to the reference materials. Persistent drug release over 87 d was observed for both ODH-based systems and both ormocer-systems, with the longest duration of activity seen for the O-ODH combination. Persistent drug release was achieved via the loosening of the polymer network indicated via decreasing polymerization enthalpies, enhanced water absorption, and water solubility. As a consequence, the flexural strengths of the materials were reduced. However, surface hardness was hardly reduced. ODH seems to be more adequate than CHX for the design of bioactive dental filling materials based on nano-hybrid ormocer and composites.
Topics: Anti-Infective Agents; Composite Resins; Dental Materials; Drug Liberation; Materials Testing; Methacrylates; Organically Modified Ceramics; Surface Properties; Water
PubMed: 34935216
DOI: 10.1111/eos.12840 -
Clinical Oral Investigations Dec 2020To perform a review on the influence of preheating and/or heating of resinous and ionomeric materials on their physical and mechanical properties and to discuss the...
OBJECTIVES
To perform a review on the influence of preheating and/or heating of resinous and ionomeric materials on their physical and mechanical properties and to discuss the benefits and methods of preheating/heating that have been used.
MATERIAL AND METHODS
A search was performed in the Pubmed, Scopus, Scielo, and gray literature databases. In vitro studies published from 1980 until now were searched using the descriptors "composite resins OR glass ionomer cements OR resin cements OR adhesives AND heating OR preheating." Data extraction and quality of work evaluation were performed by two independent evaluators.
RESULTS
At the end of reading the search titles and abstracts, 74 articles were selected. Preheating of composite resins reduces viscosity, facilitates adaptation to cavity preparation walls, increases the degree of conversion, and decreases the polymerization shrinkage. Preheating of resin cements improves strength, adhesion, and degree of conversion. Dental adhesives showed good results such as higher bond strength to dentin. However, unlike resinous materials, ionomeric materials have an increase in viscosity upon heating.
CONCLUSIONS
Preheating improves the mechanical and physical properties. However, there is a lack of clinical studies to confirm the advantages of preheating technique.
CLINICAL RELEVANCE
Preheating of dental restorative materials is a simple, safe, and successful technique. In order to achieve good results, agility and training are necessary so the material would not lose heat until the restorative procedure. Also, care is necessary to avoid bubbles and formation of gaps, which compromises the best restoration performance.
Topics: Composite Resins; Dental Bonding; Dental Cements; Dental Materials; Dentin; Glass Ionomer Cements; Heating; Materials Testing; Resin Cements
PubMed: 33083851
DOI: 10.1007/s00784-020-03637-2 -
The Science of the Total Environment Mar 2022Dental materials are currently undergoing a revolution. Mercury use, including traditional amalgam (mercury-containing) material used in dental fillings, is now being...
Dental materials are currently undergoing a revolution. Mercury use, including traditional amalgam (mercury-containing) material used in dental fillings, is now being widely regulated under the Minamata convention, and dental amalgam is currently being replaced by resin formulations in dentistry. These resin-based materials can be tuned to offer varying material properties by incorporation of a range of nano- and micro-particle based 'fillers' for different dental properties and applications. However, these innovations may have a concomitant effect on the waste streams associated with common dental applications, in particular the potential for higher concentrations of novel micro- and nanomaterials within wastewater streams, and a potential route for novel nanomaterials into the wider Environment. These new materials may also mean that wastewater filtering apparatus commonly deployed at present, such as amalgam separators, may be less efficient or insufficient to capture these new filler materials in dental facility wastewater. In this work, we analyse dental wastewater streams from three dental facilities in Ireland with differing amalgam separators in place. The potential overall toxicity, particulate load and physicochemical properties are analysed. The overall risk posed by these new materials is also discussed.
Topics: Dental Amalgam; Dental Materials; Dental Waste; Ireland; Mercury; Wastewater
PubMed: 34963598
DOI: 10.1016/j.scitotenv.2021.152632 -
Dental Materials Journal Feb 2019Polytetrafluoroethylene (PTFE) is chemically stable, non-toxic to humans, highly resistant to heat and chemicals, and has an extremely low coefficient of friction....
Polytetrafluoroethylene (PTFE) is chemically stable, non-toxic to humans, highly resistant to heat and chemicals, and has an extremely low coefficient of friction. Therefore, PTFE is used in medical applications. We focused on the physical properties of PTFE in relation to its application as a material for use in prostheses and dental devices/instruments. PTFE exhibited low wear (approximately 1/3 that of bovine tooth, and 1/2 that of type III gold alloy), low dynamic friction (approximately 1/5 that of the other specimens), low hardness (4.8HV1.0), low coloration, and low bacterial adhesion, compared to other specimens except porcelain in wear and coloration test (p<0.01). These results suggest that PTFE could have applications in some prostheses for provisional and/or permanent use, and dental instruments/devices by providing excellent impact absorption, high wear resistance for maintenance of occlusal vertical dimension and original function, and ease of cleaning.
Topics: Animals; Bacterial Adhesion; Cattle; Color; Dental Instruments; Dental Materials; Dental Porcelain; Dental Prosthesis Design; Hardness; In Vitro Techniques; Materials Testing; Polytetrafluoroethylene; Surface Properties
PubMed: 30381638
DOI: 10.4012/dmj.2018-088 -
Journal of the Mechanical Behavior of... Oct 2021The aim of this study was to investigate whether there is a relation between impact strength and flexural strength of different composite and ceramic materials used in...
AIM
The aim of this study was to investigate whether there is a relation between impact strength and flexural strength of different composite and ceramic materials used in dental restorations.
MATERIALS AND METHODS
The three-point-bending test was used to determine the flexural strength and flexural modulus, and the Dynstat impact test was used to determine the impact strength of different composite and ceramic dental materials. The relation between the flexural strength and impact strength was mathematically investigated and a three-dimensional finite element analysis model of the impact test set-up was created to verify these results.
RESULTS
We found a relation between the impact strength, a, the flexural strength, σ, and the flexural modulus, E, which can be represented by the formula: a=λ(σ⁄E), where λ is a constant dependent on the test set-up.
CONCLUSION
The obtained impact strength of materials is specific to the test set-up and dependent on the geometric configuration of the test set-up and the specimen thickness. The clinical significance of this investigation is that roughness and fatigue have far more influence on the impact strength than the flexure strength.
Topics: Ceramics; Dental Materials; Dental Porcelain; Flexural Strength; Humans; Materials Testing; Pliability; Surface Properties
PubMed: 34214922
DOI: 10.1016/j.jmbbm.2021.104658