Research and Education| Volume 128, ISSUE 3, P531-538, September 2022

Download started.


An evaluation of a technique to improve the mechanical properties of maxillofacial silicone elastomers with zinc oxide nanoparticles

Published:February 22, 2021DOI:


      Statement of problem

      Silicone elastomer is the most used material for fabricating maxillofacial prostheses, but the material has low tensile and tear strength and insufficient elasticity. Whether the addition of zinc oxide nanoparticles will improve these properties is unclear.


      The purpose of this in vitro study was to evaluate the effect of adding different concentrations of zinc oxide (ZnO) nanoparticles on the clinically critical mechanical properties of a maxillofacial silicone.

      Material and methods

      Nano-ZnO was added in concentrations of 1%, 2%, 3%, and 5% by weight to Cosmesil M511 High Temperature Vulcanization (HTV) silicone elastomer. Silicone without nano-ZnO or ethanol served as a conventional group, while silicone without nano-ZnO and with ethanol served as the control group. Tensile strength and elongation tests were done according to International Organization for Standardization (ISO) 37. A tear strength test was done according to ISO 34-1. A Shore A hardness test was done according to ISO 7619. In total 144 specimens were fabricated, with 48 specimens for each test. Field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) tests were used to assess the efficiency of the dispersion method, monitoring the particle size of nano-ZnO. Statistical analysis used 1-way ANOVA and the Tukey post hoc test (α=.05).


      FESEM showed a homogenous dispersion of ZnO nanoparticles within the silicone matrix. XRD and FESEM showed a reduction in cluster size of nano-ZnO after sonication. The FTIR-ATR test revealed no significant difference between the conventional and the control group (P>.05). The 3%ZnO demonstrated significantly higher tensile strength, elongation percentage, and tear strength than the control group (P<.05). Shore A hardness showed a significant decrease between the conventional and control group. Hardness increased directly and proportionally to an increase in the concentration of nanofiller.


      Sonication of nano-ZnO in ethanol represented an effective and straightforward way to disperse nano-ZnO in a silicone elastomer matrix. This improved the quality of the nanocomposite without affecting the base material and without the need for a coupling agent or addition of a third material. The overall mechanical properties of the M511 maxillofacial silicone elastomer improved most with a 3%ZnO concentration.
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Prosthetic Dentistry
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Dootz E.R.
        • Koran A.
        • Craig R.G.
        Physical properties of three maxillofacial materials as a function of accelerated aging.
        J Prosthet Dent. 1994; 71: 379-383
        • Aziz T.
        • Waters M.
        • Jagger R.
        Development of a new poly(dimethylsiloxane) maxillofacial prosthetic material.
        J Biomed Mater Res B Appl Biomater. 2003; 65: 252-261
        • Aziz T.
        • Waters M.
        • Jagger R.
        Analysis of the properties of silicone rubber maxillofacial prosthetic materials.
        J Dent. 2003; 31: 67-74
        • Lewis D.H.
        • Castleberry D.J.
        An assessment of recent advances in external maxillofacial materials.
        J Prosthet Dent. 1980; 43: 426-432
        • Polyzois G.L.
        • Frangou M.J.
        Bonding of silicone prosthetic elastomers to three different denture resins.
        Int J Prosthodont. 2002; 15: 535-538
        • Sweeney W.T.
        • Fischer T.E.
        • Castleberry D.J.
        • Cowperthwaite G.F.
        Evaluation of improved maxillofacial prosthetic materials.
        J Prosthet Dent. 1972; 27: 297-305
        • Udagama A.
        Urethane-lined silicone facial prostheses.
        J Prosthet Dent. 1987; 58: 351-354
        • Andreopoulos A.G.
        • Evangelatou M.
        Evaluation of various reinforcements for maxillofacial silicone elastomers.
        J Biomater Appl. 1994; 8: 344-360
        • Andreopoulos A.G.
        • Evangelatou M.
        • Tarantili P.A.
        Properties of maxillofacial silicone elastomers reinforced with silica powder.
        J Biomater Appl. 1998; 13: 66-73
        • Azhdar B.
        • Stenberg B.
        • Kari L.
        Polymer-nanofiller prepared by high-energy ball milling and high velocity cold compaction.
        Polym Compos. 2008; 29: 252-261
        • Nordell P.
        • Nawaz S.
        • Azhdar B.
        • Hillborg H.
        • Gedde U.W.
        Preparation and characterization of aluminum oxide-poly(ethylene-co-butyl acrylate) nanocomposites.
        J Appl Polym Sci. 2012; 125: 975-983
        • Jäverberg N.
        • Edin H.
        • Nordell P.
        • Nawaz S.
        • Hillborg H.
        • Azhdar B.
        • et al.
        Dielectric properties of alumina-filled poly (ethylene-co-butyl acrylate) nanocomposites Part II- wet studies.
        IEEE Trans Dielectr Electr Insul. 2012; 19: 391-399
        • Qadeer M.I.
        • Azhdar B.
        • Hedenqvist M.S.
        • Savage S.J.
        Improved oxidation resistance of SmCo magnetic alloy powders by silanization.
        Prog Org Coatings. 2013; 76: 94-100
        • Hayashi S.
        • Fujiki K.
        • Tsubokawa N.
        Grafting of hyperbranched polymers onto ultrafine silica: Postgraft polymerization of vinyl monomers initiated by pendant initiating groups of polymer chains grafted onto the surface.
        React Funct Polym. 2000; 46: 193-201
        • Khan A.A.
        • Mezbaul Alam M.
        Synthesis, characterization and analytical applications of a new and novel “organic-inorganic” composite material as a cation exchanger and Cd(II) ion-selective membrane electrode: Polyaniline Sn(IV) tungstoarsenate.
        React Funct Polym. 2003; 55: 277-290
        • Liu G.
        • Li Y.
        • Yan F.
        • Zhao Z.
        • Zhou L.
        • Xue Q.
        Effect of Nanoscale SiO2 and TiO2 as the fillers on the mechanical properties and aging behavior of linear low-density polyethylene/low-density polyethylene blends.
        J Polym Environ. 2005; 13: 339-348
        • Tang E.
        • Cheng G.
        • Pang X.
        • Ma X.
        • Xing F.
        Synthesis of nano-ZnO/poly(methyl methacrylate) composite microsphere through emulsion polymerization and its UV-shielding property.
        Colloid Polym Sci. 2006; 284: 422-428
        • Han Y.
        • Kiat-amnuay S.
        • Powers J.M.
        • Zhao Y.
        Effect of nano-oxide concentration on the mechanical properties of a maxillofacial silicone elastomer.
        J Prosthet Dent. 2008; 100: 465-473
        • Eschbach J.
        • Rouxel D.
        • Vincent B.
        • Mugnier Y.
        • Galez C.
        • Le Dantec R.
        • et al.
        Development and characterization of nanocomposite materials.
        Mater Sci Eng C. 2007; 27: 1260-1264
        • Yilmaz C.
        • Korkmaz T.
        The reinforcement effect of nano and microfillers on fracture toughness of two provisional resin materials.
        Mater Des. 2007; 28: 2063-2070
        • Shanmugharaj A.M.
        • Bae J.H.
        • Lee K.Y.
        • Noh W.H.
        • Lee S.H.
        • Ryu S.H.
        Physical and chemical characteristics of multiwalled carbon nanotubes functionalized with aminosilane and its influence on the properties of natural rubber composites.
        Compos Sci Technol. 2007; 67: 1813-1822
        • Kim J.W.
        • Kim L.U.
        • Kim C.K.
        Size control of silica nanoparticles and their surface treatment for fabrication of dental nanocomposites.
        Biomacromolecules. 2007; 8: 215-222
        • Sodagar A.
        • Bahador A.
        • Khalil S.
        • Saffar Shahroudi A.
        • Zaman Kassaee M.
        The effect of TiO2 and SiO2 nanoparticles on flexural strength of poly (methyl methacrylate) acrylic resins.
        J Prosthodont Res. 2013; 57: 15-19
        • Nguyen V.S.
        • Rouxel D.
        • Hadji R.
        • Vincent B.
        • Fort Y.
        Effect of ultrasonication and dispersion stability on the cluster size of alumina nanoscale particles in aqueous solutions.
        Ultrason Sonochem. 2011; 18: 382-388
        • Mahbubul I.M.
        • Saidur R.
        • Amalina M.A.
        Latest developments on the viscosity of nanofluids.
        Int J Heat Mass Transf. 2012; 55: 874-885
        • Ruan B.
        • Jacobi A.M.
        Ultrasonication effects on thermal and rheological properties of carbon nanotube suspensions.
        Nanoscale Res Lett. 2012; 7: 1-14
        • International Organization for Standardization
        ISO 37. Rubber, vulcanized or thermoplastic. Determination of tensile stress-strain properties.
        International Organization for Standardization, Geneva2017
        • International Organization for Standardization
        ISO 34-1. Rubber, vulcanized or thermoplastic. Determination of tear strength -Part 1: Trouser, angle and crescent test pieces.
        International Organization for Standardization, Geneva2015
        • International Organization for Standardization
        ISO 7619-1. Rubber, vulcanized or thermoplastic. Determination of indentation hardness-Part 1: Durometer method (Shore hardness).
        International Organization for Standardization, Geneva2010
        • Zhu H.
        • Li C.
        • Wu D.
        • Zhang C.
        • Yin Y.
        Preparation, characterization, viscosity and thermal conductivity of CaCO3 aqueous nanofluids.
        Sci China Technol Sci. 2010; 53: 360-368
        • Kole M.
        • Dey T.K.
        Effect of prolonged ultrasonication on the thermal conductivity of ZnO-ethylene glycol nanofluids.
        Thermochim Acta. 2012; 535: 58-65
        • Mahbubul I.M.
        • Chong T.H.
        • Khaleduzzaman S.S.
        • Shahrul I.M.
        • Saidur R.
        • Long B.D.
        • et al.
        Effect of ultrasonication duration on colloidal structure and viscosity of alumina-water nanofluid.
        Ind Eng Chem Res. 2014; 53: 6677-6684
        • Griniari P.
        • Polyzois G.
        • Papadopoulos T.
        Color and structural changes of a maxillofacial elastomer: the effects of accelerated photoaging, disinfection and type of pigments.
        J Appl Biomater Funct Mater. 2015; 13: 87-91
        • Crnich C.J.
        • Halfmann J.A.
        • Crone W.C.
        • Maki D.G.
        The effects of prolonged ethanol exposure on the mechanical properties of polyurethane and silicone catheters used for intravascular access.
        Infect Control Hosp Epidemiol. 2005; 26: 708-714
        • Frogley M.D.
        • Ravich D.
        • Wagner H.D.
        Mechanical properties of carbon nanoparticle-reinforced elastomers.
        Compos Sci Technol. 2003; 63: 1647-1654
        • Hersh J.H.
        • Podruch P.E.
        • Rogers G.
        • Weisskopf B.
        Toluene embryopathy.
        J Pediatr. 1985; 106: 922-927
        • Goodwin T.M.
        Toluene abuse and renal tubular acidosis in pregnancy.
        Obs Gynecol. 1988; 71: 715-718
        • Cohr K.H.
        • Stokholm J.
        Toluene. A toxicologic review.
        Scand J Work Environ Health. 1979; 5: 71-90
        • Wilkins-Haug L.
        Teratogen update: Toluene.
        Teratology. 1997; 55: 145-151
        • Filley C.M.
        • Halliday W.
        • Kleinschmidt-DeMasters B.K.
        The effects of toluene on the central nervous system.
        J Neuropathol Exp Neurol. 2004; 63: 1-2
        • Donald J.M.
        • Hooper K.
        • Hopenhayn-Rich C.
        Reproductive and development toxicity of toluene: A review.
        Environ Health Perspect. 1991; 94: 237-244
        • Aysa N.H.
        • Al-maamori M.H.
        Effect of the unmodified and modified ZnO nanoparticles on the mechanical and antibacterial properties of silicone rubber using in medical applications.
        J Nanosci Nanotechnol. 2015; 1: 119-124
        • Donnet J.B.
        • Custodero E.
        Reinforcement of elastomers by particulate fillers.
        in: The science and technology of rubber. 4th ed. Academic Press/Elsevier, San Diego2013: 383-416
        • Sun L.
        • Gibson R.F.
        • Gordaninejad F.
        • Suhr J.
        Energy absorption capability of nanocomposites: A review.
        Compos Sci Technol. 2009; 69: 2392-2409
        • May P.D.
        • Guerra L.R.
        Maxillofacial prostheses of chlorinated polyethylene.
        J Biomed Mater Res. 1978; 12: 421-431
        • Yoo S.H.
        • Cohen C.
        • Hui C.Y.
        Mechanical and swelling properties of PDMS interpenetrating polymer networks.
        Polymer. 2006; 47: 6226-6235
        • Qamar S.Z.
        • Al-Hiddabi S.A.
        • Pervez T.
        • Marketz F.
        Mechanical testing and characterization of a swelling elastomer.
        J Elastomers Plast. 2009; 41: 415-431
        • Hu Y.
        • Chen X.
        • Whitesides G.M.
        • Vlassak J.J.
        • Suo Z.
        Indentation of polydimethylsiloxane submerged in organic solvents.
        J Mater Res. 2011; 26: 785-795
        • Li C.H.
        • Liao P.L.
        • Shyu M.K.
        • Liu C.W.
        • Kao C.C.
        • Huang S.H.
        • et al.
        Zinc oxide nanoparticles-induced intercellular adhesion molecule 1 expression requires Rac1/Cdc42, mixed lineage kinase 3, and c-Jun N-terminal kinase activation in endothelial cells.
        Toxicol Sci. 2012; 126: 162-172
        • Osmond G.
        • Boon J.J.
        • Puskar L.
        • Drennan J.
        Metal stearate distributions in modern artists’ oil paints: Surface and cross-sectional investigation of reference paint films using conventional and synchrotron infrared microspectroscopy.
        Appl Spectrosc. 2012; 66: 1136-1144
        • Goiato M.C.
        • Haddad M.F.
        • Santos DM dos
        • Pesqueira A.A.
        • Moreno A.
        Hardness evaluation of prosthetic silicones containing opacifiers following chemical disinfection and accelerated aging.
        Braz Oral Res. 2017; 24: 303-308
        • Eleni P.N.
        • Krokida M.K.
        • Polyzois G.L.
        • Gettleman L.
        Effect of different disinfecting procedures on the hardness and color stability of two maxillofacial elastomers over time.
        J Appl Oral Sci. 2013; 21: 278-283