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Flexural strength, biocompatibility, and antimicrobial activity of a polymethyl methacrylate denture resin enhanced with graphene and silver nanoparticles

  • Cecilia Bacali
  • Ioana BaldeaEmail author
  • Marioara Moldovan
  • Rahela Carpa
  • Diana Elena Olteanu
  • Gabriela Adriana Filip
  • Vivi Nastase
  • Liana Lascu
  • Mandra Badea
  • Mariana ConstantiniucEmail author
  • Florin Badea
Original Article

Abstract

Objective

The study evaluates the effect of adding graphene-Ag nanoparticles (G-AgNp) to a PMMA auto-polymerizing resin, with focus on antibacterial activity, cytotoxicity, monomer release, and mechanical properties.

Materials and methods

Auto-polymerizing acrylic resin (M) was loaded with 1 wt% G-AgNp (P1) and 2 wt% G-AgNp (P2). Methyl methacrylate monomer release (MMA) was measured after immersion of the samples in chloroform and cell medium respectively. Cell viability was assessed on dysplastic oral keratinocytes (DOK) and dental pulp stem cells. Oxidative stress and inflammatory response following exposure of dysplastic oral keratinocytes to the experimental resins was evaluated. Antibacterial activity against Staphylococcus aureus, Streptococcus mutans and Escherichia coli and also flexural strength of the resins were assessed.

Results

Residual monomer: For samples immersed in chloroform, MMA concentration reached high levels, 10.27 μg/g for sample P1; MMA increased at higher G-AgNp loading; 0.63 μg/g MMA was found in medium for P1, and less for sample P2. Cell viability: Both cell lines displayed a viability decrease, but remained above 75%, compared to controls, when exposed to undiluted samples. Inflammation: proinflammatory molecule TNF-α decreased when DOK cultures were exposed to G-AgNp samples. MDA levels indicated increased oxidative stress damage in cells treated with PMMA, confirmed by the antioxidant mechanism activation, while samples containing G-AgNp induced an antioxidant effect. All tested samples showed antibacterial properties against Gram-positive bacteria. Samples containing G-AgNp also exhibited bactericide action on E. coli. Mechanical properties: both samples containing G-AgNp improved flexural strength compared to the sample resin, measured through elastic strength parameters.

Conclusions

PMMA resin loaded with G-AgNp presents promising antibacterial activity associated with minimal toxicity to human cells, in vitro, as well as improved flexural properties.

Clinical relevance

These encouraging results obtained in vitro support further in vivo investigation, to thoroughly check whether the PMMA loaded with graphene-silver nanoparticles constitute an improvement over current denture materials.

Keywords

PMMA resin Graphene Silver nanoparticles Antibacterial action Biocompatibility 

Notes

Author contribution

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Cecilia Bacali, Ioana Baldea, Marioara Moldovan, Rahela Carpa and Diana Elena Olteanu. The first draft of the manuscript was written by Cecilia Bacali, Ioana Baldea, Marioara Moldovan and Rahela Carpa. All authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Funding information

The work was supported by the University of Medicine and Pharmacy “Iuliu Hatieganu” Cluj-Napoca, Romania, grant number PCD 7690/76/15.04.2016.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

This article does not contain any studies with human participants or animals performed by any of the authors.

Informed consent

For this type of study, formal consent is not required.

References

  1. 1.
    Naik AV (2009) Complete denture fractures: A clinical study. J Indian Prosthodont Soc 9:148–150.  https://doi.org/10.4103/0972-4052.57084 CrossRefGoogle Scholar
  2. 2.
    Shakir S, Jalil H, Khan MA, Qayum B, Qadeer A (2017) Causes and types of denture fractures. Pakistan Oral Dental J 37(4):634–637Google Scholar
  3. 3.
    Darbar UR, Huggett R, Harrison A (1994) Denture fracture-a survey. Br Dent J 176(9):342–345.  https://doi.org/10.1038/sj.bdj.4808449 CrossRefPubMedGoogle Scholar
  4. 4.
    Gendreau L, Loewy ZG (2011) Epidemiology and etiology of denture stomatitis. J Prosthodont 20(4):251–260CrossRefGoogle Scholar
  5. 5.
    Stein PS, Sullivan J, Haubenreich JE, Osborne PB (2005) Composite resin in medicine and dentistry. J Long-Term Eff Med Implants 15(6):641–654.  https://doi.org/10.1615/JLongTermEffMedImplants.v15.i6.70 CrossRefPubMedGoogle Scholar
  6. 6.
    Frazer RQ, Byron RT, Osborne PB, West KP (2005) PMMA: An essential material in medicine and dentistry. J LongTermEff Med Implants 15(6):629–639.  https://doi.org/10.1615//JLongTermEffMedImplants.v15.i6.60 CrossRefGoogle Scholar
  7. 7.
    Karthick R, Sirisha P, Ravi SM (2014 Dec) Mechanical and tribological properties of PMMA-sea shell based biocomposite for dental applications. Procedia Mater Sci 6:1989–2000.  https://doi.org/10.1016/j.mspro.2014.07.234 CrossRefGoogle Scholar
  8. 8.
    Golbidi F, Amini PM (2017) Flexural strength of polymethyl methacrylate repaired with fiberglass. J Dent (Tehran, Iran) 14(4):231–236Google Scholar
  9. 9.
    Liu J, Ge Y, Xu L (2012) Study of antibacterial effect of polymethyl methacrylate resin base containing Ag-TiO2 against Streptococcus mutans and Saccharomyces albicans in vitro. West China J Stomatol 30(2):201–205Google Scholar
  10. 10.
    Weaver R, Goebel W (1980) Reactions to acrylic resin dental prostheses. J Prosthet Dent 43(2):138–142.  https://doi.org/10.1016/0022-3913(80)90176-6 CrossRefGoogle Scholar
  11. 11.
    Leggat PA, Kedjarune U (2003) Toxicity of methyl methacrylate in dentistry. Int Dent J 53(3):126–131.  https://doi.org/10.1111/j.1875-595X.2003.tb00736.x CrossRefPubMedGoogle Scholar
  12. 12.
    Xie H, Cao T, Rodriguez-Lozano FJ, Luong-Van EK, Rosa V (2017 Jul) Graphene for the development of the next-generation of bios for dental and medical applications. Dent Mater 33(7):765–774.  https://doi.org/10.1016/j.dental.2017.04.008 CrossRefPubMedGoogle Scholar
  13. 13.
    Lee JH, Jo JK, Kim DA, Patel KD, Kim HW, Lee HH (2018 Apr) Nano-graphene oxide incorporated into PMMA resin to prevent microbial adhesion. Dent Mater 34(4):e63–e72.  https://doi.org/10.1016/j.dental.2018.01.019 CrossRefPubMedGoogle Scholar
  14. 14.
    Bacali C, Badea M, Moldovan M, Sarosi C, Nastase V, Baldea I, Chiorean RS, Constantiniuc M (2019 Jul) The influence of graphene in improvement of physic-mechanical properties in PMMA Denture Base Resins. Materials (Basel) 12(14):2335CrossRefGoogle Scholar
  15. 15.
    Bacali C, Buduru S, Nastase V, Craciun A, Prodan D, Constantiniuc M, Badea M, Moldovan M, Sarosi C (2019) Solubility, ductility and resilience of a PMMA denture resin with graphene and silver nanoparticles addition. Stud UBB Chem 64:471–481CrossRefGoogle Scholar
  16. 16.
    Sun L, Yan Z, Duan Y, Zhang J, Liu B (2018) Improvement of the mechanical, tribological and antibacterial properties of glass ionomer cements by fluorinated graphene. Dent Mater 34(3):e115–e127.  https://doi.org/10.1016/j.dental.2018.02.006 CrossRefPubMedGoogle Scholar
  17. 17.
    Sava S, Moldovan M, Sarosi C, Mesasros A, Dudea D, Alb C (2015) Effects of graphene addition on the mechanical properties of composites for dental restoration. Mater Plast 52(1):90–92Google Scholar
  18. 18.
    Monzavi A (2015) & Eshraghi, Saeed & Hashemian, Roxana & Momen-Heravi, Fatemeh. In vitro and ex vivo antimicrobial efficacy of nano-MgO in the elimination of endodontic pathogens. Clin Oral Investig 19(2):349–356.  https://doi.org/10.1007/s00784-014-1253-y CrossRefPubMedGoogle Scholar
  19. 19.
    Acosta-Torres L, Mendieta A, Nuñez R, Cajero-Juárez M, Castaño V (2012) Cytocompatible antifungal acrylic resin containing silver nanoparticles for dentures. Int J Nanomedicine 7:4777–4786.  https://doi.org/10.2147/IJN.S32391 CrossRefPubMedPubMedCentralGoogle Scholar
  20. 20.
    Gad M, Fouda SM, Al-Harbi FA, Näpänkangas R, Raustia A (2017) PMMA denture base material enhancement: A review of fiber, filler, and nanofiller addition. Int J Nanomedicine 12:3801–3812.  https://doi.org/10.2147/IJN.S130722 CrossRefPubMedPubMedCentralGoogle Scholar
  21. 21.
    Geim AK, Novoselov KS (2007) The rise of graphene. Nat Mater 6(3):183–191CrossRefGoogle Scholar
  22. 22.
    Kumar P, Huo P, Zhang R, Liu B (2019) Antibacterial properties of graphene-based nanomaterials. Nanomaterials (Basel) 9(5):737CrossRefGoogle Scholar
  23. 23.
    Liu S, Zeng TH, Hofmann M, Burcombe E, Wei J, Jiang R, Kong J, Chen Y (2011) Antibacterial activity of graphite, graphite oxide and reduced graphene oxide: membrane and oxidative stress. ACS Nano 5(9):6971–6980CrossRefGoogle Scholar
  24. 24.
    Jatania A, Shivalinga BM (2014) An in vitro study to evaluate the effects of addition of zinc oxide to an orthodontic bonding agent. Eur J Dent 8(1):112–117.  https://doi.org/10.4103/1305-7456.126262 CrossRefPubMedPubMedCentralGoogle Scholar
  25. 25.
    Olteanu D, Filip A, Socaci C, Biris AR, Filip X, Coros M, Rosu MC, Pogacean F, Alb C, Baldea I, Bolfa P, Pruneanu S (2015 Dec 1) Cytotoxicity assessment of graphene-based nanomaterials on human dental follicle stem cells. Colloids Surf B: Biointerfaces 136:791–798.  https://doi.org/10.1016/j.colsurfb.2015.10.023 CrossRefPubMedGoogle Scholar
  26. 26.
    Zhang B, Wei P, Zhou Z, Wei T (2016 Oct 1) Interactions of graphene with mammalian cells: molecular mechanisms and biomedical insights. Adv Drug Deliv Rev 105:145–162.  https://doi.org/10.1016/j.addr.2016.08.009 CrossRefPubMedGoogle Scholar
  27. 27.
    Danesh G, Hellak T, Reinhardt K, Vegh A, Schafer E, Lippold C (2012) Elution characteristics of residual monomers in different light-and auto-curing resins. Exp Toxicol Pathol 64(7-8):867–872.  https://doi.org/10.1016/j.etp.2011.03.008 CrossRefPubMedGoogle Scholar
  28. 28.
    Baldea I, Costin G-E, Shellman Y, Kechris K, Olteanu ED, Filip A, Cosgarea MR, Norris DA, Birlea SA Biphasic pro-melanogenic and pro-apoptotic effects of all-trans- retinoic acid (ATRA) on human melanocytes: time-course study. J Dermatol Sci 72(2):168–176.  https://doi.org/10.1016/j.jdermsci.2013.06.004 CrossRefGoogle Scholar
  29. 29.
    Baldea I, Olteanu DE, Bolfa P, Ion RM, Decea N, Cenariu M, Banciu M, Sesarman AV, Filip AG (2015) Efficiency of photodynamic therapy on WM35 melanoma with synthetic porphyrins: role of chemical structure, intracellular targeting and antioxidant defense. J Photochem Photobiol B 151:142–152.  https://doi.org/10.1016/j.jphotobiol.2015.07.019 CrossRefPubMedGoogle Scholar
  30. 30.
    Balouiri M, Sadiki M, Ibnsouda SK (2016) Methods for in vitro evaluating antimicrobial activity: a review. J Pharm Anal 6(2):71–79.  https://doi.org/10.1016/j.jpha.2015.11.005 CrossRefPubMedGoogle Scholar
  31. 31.
    Bural C, Aktas E, Deniz G, Unlucerci Y, Kizilcan N, Bayraktar G (2011) Effect of post-polymerization heat-treatments on degree of conversion, leaching residual MMA and in vitro cytotoxicity of autopolymerizing acrylic repair resin. Dent Mater 27(11):1135–1143.  https://doi.org/10.1016/j.dental.2011.08.007 CrossRefPubMedGoogle Scholar
  32. 32.
    Goldberg M (2008) In Vitro and in vivo studies on the toxicity of dental resin components: a review. Clin Oral Investig 12(1):1–8.  https://doi.org/10.1007/s00784-007-0162-8 CrossRefPubMedGoogle Scholar
  33. 33.
    De Andrade Lima Chaves C, Machado AL, Vergani CE, Freitas de Souza R, Giampaolo ET (2012) Cytotoxicity of denture base and hard chairside reline materials: a systematic review. J Prosthetic Dent 107(2):114–127.  https://doi.org/10.1016/S0022-3913(12)60037-7 CrossRefGoogle Scholar
  34. 34.
    Al-Hiyasat A, Darmani H, Milhem MM (2005) cytotoxicity evaluation of dental resin composites and their flowable derivatives. Clin Oral Investig 9(1):21–25.  https://doi.org/10.1007/s00784-004-0293-0 CrossRefPubMedGoogle Scholar
  35. 35.
    Paz E, Forriol F, del Real JC, Dunne N (2017) Graphene oxide versus graphene for optimization of PMMA bone cement for orthopaedic applications. Mater Sci Eng C Mater Biol Appl 77:1003–1011.  https://doi.org/10.1016/j.msec.2017.03.269 CrossRefPubMedGoogle Scholar
  36. 36.
    Segerstrom S, Sandborgh-Englund G, Ruyter EI (2011 Jun) Biological and physiochemical properties of carbon-graphite fibre-reinforced polymers intended for implant suprastructures. Eur J Oral Sci 119(3):246–252.  https://doi.org/10.1111/j.1600-0722.2011.00826.x CrossRefPubMedGoogle Scholar
  37. 37.
    Charasseangpaisarn T, Wiwatwarrapan C, Leklerssiriwong N (2016 Dec) Ultrasonic cleaning reduces the residual monomer in acrylic resins. J Dent Sci 11(4):443–448.  https://doi.org/10.1016/j.jds.2016.07.003 CrossRefPubMedPubMedCentralGoogle Scholar
  38. 38.
    Mesaros AS, Romanec C, Mesaros M, Moldovan M (2017) In vitro testing of experimental and commercial bracket bonding materials. Mater Plast 54(4):620–625Google Scholar
  39. 39.
    Chang SE, Foster S, Betts D, Marnock WE (1992 Dec 2) DOK, a cell line established from human dysplastic oral mucosa, shows a partially transformed non-malignant phenotype. Int J Cancer 52(6):896–902.  https://doi.org/10.1002/ijc.2910520612 CrossRefPubMedGoogle Scholar
  40. 40.
    Souid-Mensi G, Moukha S, Mobio TA, Maaroufi K, Creppy EE (2008) The cytotoxicity and genotoxicity of okadaic acid are cell-line dependent. Toxicon 51(8):1338–1344.  https://doi.org/10.1016/jtoxicon.2008.03.002 CrossRefPubMedGoogle Scholar
  41. 41.
    Yoshioka R, Nakashima Y, Fujiwara Y, Komohara Y, Takeya M, Nakanishi Y (2016) The biological response of macrophages to PMMA particles with different morphology and size. Biosurf Biotribol 2(3):114–120.  https://doi.org/10.1016/j.bsbt.2016.09.003 CrossRefGoogle Scholar
  42. 42.
    Da Silva EVF, Goiato C, da Rocha Bonatto L, de Medeiros RA, dos Santos DM, Rangel EC, de Oliveira SHP (2016) Toxicity analysis of ocular prosthesis acrylic resin with or without pigment incorporation in human conjunctival cell line. Toxicol In Vitro 36:180–185.  https://doi.org/10.1016/j.tiv.2016.08.005 CrossRefPubMedGoogle Scholar
  43. 43.
    Qu Y, He F, Yu C, Liang X, Liang D, Ma L, Zhang LJ, Wu J (2018 Sept 1) Advances on graphene-based nanomaterials for biomedical applications. Mater Sci Eng C Mater Biol Appl 90:764–780.  https://doi.org/10.1016/j.msec.2018.05.018 CrossRefPubMedGoogle Scholar
  44. 44.
    Siczek K, Zatorski H, Ghmielowiek-Korzeniowska A, Kordek L, Tymczyna L, Fichna J (2017 Jun) Evaluation of anti-inflammatory effect of silver-coated glass beads in mice with experimentally induced colitis as a new type of treatment in inflammatory bowel disease. Pharmacol Rep 69(3):386–392.  https://doi.org/10.1016/j.pharep.2017.01.003 CrossRefPubMedGoogle Scholar
  45. 45.
    Carmel-Harel O, Storz G (2000) Roles of the glutathione- and thioredoxin-dependent reduction systems in the Escherichia coli and Saccharomyces cerevisiae responses to oxidative stress. Annu Rev Microbiol 54:439–461.  https://doi.org/10.1146/annurev.micro.54.1.439 CrossRefPubMedGoogle Scholar
  46. 46.
    Ravindran A, Chandran P, Khan SS (2013) Biofunctionalized silver nanoparticles: Advances and prospects. Colloids Surf B: Biointerfaces 105:342–352.  https://doi.org/10.1016/j.colsurfb.2012.07.036 CrossRefPubMedGoogle Scholar
  47. 47.
    Jaworski S, Wierzbicki M, Sawosz E, Jung A, Gielerak G, Biernat J, Jaremek H, Łojkowski W, Woźniak B, Wojnarowicz J, Stobiński L, Małolepszy A, Mazurkiewicz-Pawlicka M, Łojkowski M, Kurantowicz N, Chwalibog A (2018) Graphene oxide-based nanocomposites decorated with silver nanoparticles as an antibacterial agent. Nanoscale Res Lett 13:116.  https://doi.org/10.1186/s11671-018-2533-2 CrossRefPubMedPubMedCentralGoogle Scholar
  48. 48.
    Gurunathan S, Han JW, Park JH, Kim E, ChoiYJ KDN, Kim JH (2015 Oct 5) Reduced graphene oxide–silver nanoparticle nanocomposite: a potential anticancer nanotherapy. Int J Nanomedicine 10:6257–6276.  https://doi.org/10.2147/IJN.S92449 CrossRefPubMedPubMedCentralGoogle Scholar
  49. 49.
    Vi TTT, Rajesh Kumar S, Rout B, Liu CH, Wong CB, Chang CW, Chen CH, Chen DW, Lue SJ (2018) The preparation of graphene oxide-silver nanocomposites: the effect of silver loads on gram-positive and gram-negative antibacterial activities. Nanomaterials 8(3):163.  https://doi.org/10.3390/nano8030163 CrossRefPubMedCentralGoogle Scholar
  50. 50.
    Kim JS, Kuk E, Yu KN, Kim JH, Park SJ, Lee HJ, Kim SH, Park YK, Hwang CY, Kim YK, Lee YS, Jeong DH, Cho MH (2007) Antimicrobial effects of silver nanoparticles. Nanomedicine 3(1):95–101.  https://doi.org/10.1016/j.nano.2006.12.001 CrossRefPubMedGoogle Scholar
  51. 51.
    Duran N, Duran M, de Jesus MB, Seabra AB, Favaro WJ, Nakazato G (2016) Silver nanoparticles: a new view on mechanistic aspects on antimicrobial activity. Nanomedicine 12(3):789–799.  https://doi.org/10.1016/j.nano.2015.11.016 CrossRefPubMedGoogle Scholar
  52. 52.
    Prabhu S, Poulose E (2012) Silver nanoparticles: mechanism of antimicrobial action, synthesis, medical applications, and toxicity effects. Int Nano Let 2:32.  https://doi.org/10.1186/2228-5326-2-32 CrossRefGoogle Scholar
  53. 53.
    Chwalibog A, Sawosz E, Hotowy A, Szeliga J, Mitura S, Mitura K, Grodzik M, Orłowski P, Sokolowska A (2010) Visualization of interaction between inorganic nanoparticles and bacteria or fungi. Int J Nanomedicine 5:1085–1094.  https://doi.org/10.2147/IJN.S13532 CrossRefPubMedPubMedCentralGoogle Scholar
  54. 54.
    Maleki Dizaj S, Mennati A, Jafari S, Khezri K, Adibkia K (2015) Antimicrobial activity of carbon-based nanoparticles. Adv Pharm Bull 5(1):19–23.  https://doi.org/10.5681/apb.2015.003 CrossRefPubMedPubMedCentralGoogle Scholar
  55. 55.
    Petrochenko PE, Zheng J, Casey BJ, Reza Bayati M, Narayan RJ, Goering PL (2017 Oct) Nanosilver-PMMA coating optimized to provide robust antibacterial efficacy while minimizing human bone marrow stromal cell toxicity. Toxicol in Vitro 44:248–255.  https://doi.org/10.1016/j.tiv.2017.07.014 CrossRefPubMedGoogle Scholar
  56. 56.
    Zhuang C, She Y, Zhang H, Han Y, Li Y, Zhu Y (2018) Cytoprotective effect of deferiprone against aluminium chloride-induced oxidative stress and apoptosis in lymphocytes. Toxicol Lett 285:132–138.  https://doi.org/10.1016/j.toxlet.2018.01.007 CrossRefPubMedGoogle Scholar
  57. 57.
    Li J, Wang G, Zhu H, Zhang M, Zheng X, Di Z, Liu X, Wang X (2014) Antibacterial activity of large-area monolayer graphene film manipulated by charge transfer. Sci Rep 4:4359.  https://doi.org/10.1038/srep04359 CrossRefPubMedPubMedCentralGoogle Scholar
  58. 58.
    De Moraes AC, Lima BA, de Faria AF, Brocchi M, Alves OL (2015) Graphene oxide-silver nanocomposite as a promising biocidal agent against methicillin-resistant Staphylococcus aureus. Int J Nanomedicine 10:6847–6861.  https://doi.org/10.2147/IJN.S90660 CrossRefPubMedPubMedCentralGoogle Scholar
  59. 59.
    Xu WP, Zhang LC, Li JP, Lu Y, Li HH, Ma YN, Wang WD, Yu SH (2011) Facile synthesis of silver@graphene oxide nanocomposites and their enhanced antibacterial properties. J Mater Chem 21(12):4593–4597.  https://doi.org/10.1039/C0JM03376F CrossRefGoogle Scholar
  60. 60.
    Moldovan M, Prodan D, Sarosi C, Carpa R, Socaci C, Rosu MC (2018) Pruneanu. Synthesis, morpho-structural properties and antibacterial effect of silicate based containing graphene oxide/hydroxyapatite. Mater Chem Phys 217:48–53.  https://doi.org/10.1016/j.matchemphys.2018.06.055 CrossRefGoogle Scholar
  61. 61.
    Ajaj-ALKordy NM, Alsadi MH (2014) Elastic modulus and flexural strength comparisons of high-impact and traditional denture base acrylic resins. Saudi Dent J 1:15–18.  https://doi.org/10.1016/jdentj.2013.12.005 CrossRefGoogle Scholar
  62. 62.
    Neelgund GM, Oki A, Luo Z (2013) In situ deposition of hydroxyapatite on graphene nanosheets. Mater Res Bull 48(2):175–179.  https://doi.org/10.1016/j.materresbull.2012.08.077 CrossRefPubMedPubMedCentralGoogle Scholar
  63. 63.
    Papageorgiu DG, Kinloch IA, Young RJ (2017) Mechanical properties of graphene and graphene-based nanocomposites. Progr Mat Sci 90:75–6425.  https://doi.org/10.1016/jmatsci.2017.07.004 CrossRefGoogle Scholar
  64. 64.
    Kumar S, Mahajan M, Singh R, Mahajan A. Silver nanoparticles anchored reduced graphene oxide for enhanced electrocatalytic activity towards methanol oxidation. Chem Phys Lett 693.  https://doi.org/10.1016/j.cplett.2018.01.003.CrossRefGoogle Scholar
  65. 65.
    Hashem M, Fayez Al Rez M, Fouad H, Elsarnagawy T, Elsharawy M, Umar A, Assery M, Ansary S (2017) Influence of titanium oxide nanoparticles on the physical and thermomechanical behavior of poly methyl methacrylate (PMMA): A denture base resin. Sci Adv Mater 9(6):938–944(7).  https://doi.org/10.1166/sam.2017.3087 CrossRefGoogle Scholar
  66. 66.
    Somkuwar S, Mishra S, Agrawal B, Choura R (2017) Comparison of flexural strength of polymethyl methacrylate resin reinforced with multiwalled carbon nanotubes and processed by conventional water bath technique and microwave polymerization. J Indian Prosthodont Soc 17(4):332–339.  https://doi.org/10.4103/jips.jips.137.17 CrossRefPubMedPubMedCentralGoogle Scholar
  67. 67.
    Arendorf TM, Walker DM (1987) Denture stomatitis: a review. J Oral Rehabil 14(3):217–227CrossRefGoogle Scholar
  68. 68.
    Ma J, Zhang J, Xiong Z, Yong Y, Zhao XS (2011) Preparation, characterization and antibacterial properties of silver-modified graphene oxide. J Mater Chem 21:3350.  https://doi.org/10.1039/c0jm02806a CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Prosthodontics and Dental MaterialsIuliu Hatieganu University of Medicine and PharmacyCluj-NapocaRomania
  2. 2.Department of PhysiologyIuliu Hatieganu University of Medicine and PharmacyCluj-NapocaRomania
  3. 3.Raluca Ripan Institute for Research in ChemistryBabeș Bolyai UniversityCluj-NapocaRomania
  4. 4.Faculty of Biology and Geology, Department of Molecular Biology and BiotechnologyBabeș Bolyai UniversityCluj-NapocaRomania
  5. 5.Institute for Computational LinguisticsUniversity of HeidelbergHeidelbergGermany
  6. 6.Department of Preventive Dental MedicineIuliu Hatieganu University of Medicine and PharmacyCluj-NapocaRomania
  7. 7.Department, of Anatomy and EmbryologyIuliu Hatieganu University of Medicine and PharmacyCluj-NapocaRomania

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