ORIGINAL RESEARCH Year : 2023  |  Volume : 14  |  Issue : 1  |  Page : 19-21

Effect of Incorporation of Boron Nitride Nanoparticles on Impact Strength and Surface Roughness of Heat Cure Poly Methyl Methacrylate Resin: An In Vitro Study

Hussein Ali M Hussein1, Hikmat J Al-Judy2
1 Department of Prosthodontic, College of Dentistry, University of Kufa, Najaf, Iraq
2 Department of Prosthodontic, College of Dentistry, University of Baghdad, Baghdad, Iraq

Date of Submission16-Nov-2022Date of Decision15-Dec-2022Date of Acceptance17-Dec-2022Date of Web Publication20-Mar-2023

Correspondence Address:
Hussein Ali M Hussein
Department of Prosthodontic, College of Dentistry, University of Kufa, Najaf
Iraq

Source of Support: None, Conflict of Interest: None

Check

DOI: 10.4103/denthyp.denthyp_140_22

Background: The objective of this research was to explore how the addition of boron nitride (BN) nanoparticles in the concentrations of 1% and 1.5% w/w affect the impact strength and surface roughness of heat-cured poly methyl methacrylate resin (PMMA). Methods: Sixty specimens were made from heat-cured acrylic resin and then divided into control, 1%, and 1.5% w/w BN groups. The impact strength and surface roughness were investigated. One-way ANOVA and Tukey’s post hoc test were used for data analysis. Results: Statistically significant difference is found among the three study groups regarding impact strength (P = 0.011) and surface roughness test (P <  0.001). The post hoc test showed significant differences for all multiple comparisons for the surface roughness test (P < 0.001). Yet, multiple comparisons for the impact strength test revealed only a significant difference between the 1.5% BN and control groups (P = 0.005). Conclusion: The addition of boron BN into PMMA improves impact strength with 1.5% concentration; while adversely increase the surface roughness.

Keywords: Boron nitride, denture base, heat cure acrylic resin, impact strength, nanoparticle, poly methyl methacrylate, surface roughness

How to cite this article:
Hussein HM, Al-Judy HJ. Effect of Incorporation of Boron Nitride Nanoparticles on Impact Strength and Surface Roughness of Heat Cure Poly Methyl Methacrylate Resin: An In Vitro Study. Dent Hypotheses 2023;14:19-21
How to cite this URL:
Hussein HM, Al-Judy HJ. Effect of Incorporation of Boron Nitride Nanoparticles on Impact Strength and Surface Roughness of Heat Cure Poly Methyl Methacrylate Resin: An In Vitro Study. Dent Hypotheses [serial online] 2023 [cited 2023 Mar 21];14:19-21. Available from: http://www.dentalhypotheses.com/text.asp?2023/14/1/19/372087   Introduction 

Polymethyl methacrylate (PMMA) is a popular polymer because of its optical properties, biocompatibility, and attractive look. Acrylic resin, however, is not an ideal biomaterial because of its inadequate impact strength and fatigue resistance. Biting forces, temperature variations, exposure to saliva, water, acidic foods, and mechanical impacts are just some of the factors that can cause damage to the denture base over time.[1],[2] One of the most commonly used denture base materials is PMMA, but an optimal material has yet to be discovered.[3]

The denture can break in two ways: either by impact, as when it is dropped on a hard surface, or by fatigue, as when the denture base deforms repeatedly because of occlusal forces.

Nowadays, more focus is being placed on the inclusion of various components, such as rubber, fibers, or nanosilver into PMMA in order to enhance its physical properties.[4],[5],[6]

Boron nitride (BN) is a refractory material that exhibits notable thermal and chemical resistance. Its chemical structure is comparable to that of graphene (carbon 2D material).

BN is wildly used in dental science, for instance reinforcement of dental ceramics,[7] filler of resin-based dental sealants,[8] to increase properties of dental adhesives,[9],[10] as a coating for dental implants,[11] as fillers for dental resin composite.[12]

However, the objective of this research was to explore how the addition of BN nanoparticles in the concentration of 1% and 1.5% w/w affects the impact strength and surface roughness of heat-cured PMMA.

  Materials and methods 

Study protocol approved by the local ethical committee of College of Dentistry, University of Baghdad (approval number (13) on March 01, 2022). Sixty specimens were prepared from heat-cured resin (Rodex, Bagcilar, Turkey). And impact strength test and a surface roughness test were carried out among the study groups: the control group (PMMA without BN) (n = 10), PMMA specimens containing 1% (n = 10), and 1.5% w/w BN (n = 10). (BN, hexagonal, 99.99%, 3–4 um) (SkySpring Nanomaterials, Inc., Houston, USA) was mixed with the monomer liquid to make the acrylic dough for the experimental groups. The BN was thoroughly dispersed using a probe sonicator apparatus (Soniprep-150, Imgen Technologies LLC, Alexandria, USA) for 3 minutes to ensure good BN dispersion and prevent agglomeration within the monomer. Imgen Technologies LLC.

Impact strength test

The acrylic samples for the impact strength test were fabricated with dimensions of 80 × 10 × 4 mm in length, width, and thickness respectively and were maintained in distilled water at 37 °C for 2 days before being tested according to ADA specification No.12.[13]Charpy impact testing instrument (TMI, Testing Machine Inc., New York, USA) used in accordance with the guidelines laid out in ISO 179-1.

Surface roughness test

The acrylic samples of the impact strength test were fabricated with dimensions of 65 × 10 × 2.5 mm in length, width, and thickness, respectively, and were stored in distilled water at 37 °C for 2 days before being tested in accordance.[13] The profilometer apparatus (TEREN, DaLian, China) was used to examine the microstructure geometry of the test specimens.

Statistical methods

Data were analyzed using one-way ANOVA and Tukey’s post hoc test using R software (R Foundation for Statistical Computing, Vienna, Austria).

  Results 

The statistically significant difference was found among the three study groups regarding impact strength (P = 0.011) and surface roughness test (P <  0.001). The Post hoc test showed significant differences for all multiple comparisons for the surface roughness test (P < 0.001). Yet, multiple comparisons for the impact strength test revealed a significant difference between the 1.5% BN and control (0% BN) group (P = 0.005) and a non-significant difference between the 1% BN versus control group (P = 0.020) and 1% BN versus 1.5% BN group (P = 0.023) [Figure 1].

Figure 1 Box and whisker plot depicted summary statistics related to impact strength and roughness test.

Click here to view

  Discussion 

The resistance of an acrylic denture base to cracking when faced with an unexpected, intense force, such as when dropped, is a crucial quality. For this research, we utilized the Charpy impact testing equipment, which is well recognized as one of the most popular techniques for determining the relative toughness of a material in a time- and cost-efficient manner. In this study, the addition of 1% and 1.5% BN reduced the mean value of impact strength in comparison with the control group. This reduction was statistically insignificant for the 1.5% BN group.

The research of Gaffari et al., reported a similar finding, discovering a decrease in strength with the addition of silver nanoparticles.[14] Ihab et al., assessed the effect of addition of the ZrO2 nanoparticles into PMMA and found a significant rise in impact and transverse strength at concentration of 5%, but a non-significant increase was observed at 7%.[15] This reduction may be caused by a rise in the number of particles, each of which serves as a focal point for a localized region of high stress. As a result of their influence on the interface area at high concentrations, reinforcing materials help to minimize the loss of energy during testing.[16] In contrast, Alqahtani reported that the addition of 5% BN increased the flexural strength, Vickers hardness and the modulus of elasticity.[17],[18] Kamil and Al-Judy examined the addition of silicon carbide nanoparticles to PMMA and reported a non-significant decrease in impact strength.[19] Also, Alwan and Alameer reported a significant increase in impact and transverse strength with the addition of TiO2 nanoparticles to PMMA.[20]

However, increased surface roughness allows the development of bacterial plaque and stains on the denture, which has a negative effect on the hygiene and esthetics of dentures. The esthetic features and biofilm adhesion are both affected by the initial surface roughness.[21]

This study used a profilometer device, which has been recognized as a high-quality device for the assessment of surface roughness. The present study’s findings showed that the addition of BN reduced surface roughness. Our findings are in accordance with the outcomes of Mangal et al., who revealed that the addition of diamond filler resulted in a reduction in surface roughness.[22] In contrast, Ahmed et al. showed the incorporation of silanized SiO2 nanoparticles and oxygen plasma-treated polypropylene fiber to heat cure PMMA and increase surface roughness of acrylic resin.[23] Kamil and Al-Judy reported a significant increase in surface roughness after the addition of silicon carbide nanoparticles.[19] Alwan and Alameer showed a significant increase in surface roughness with the incorporation of TiO2 nanoparticles into PMMA.[20] Inconsistency aside, Ihab et al. reported non-significant increases in surface roughness following the addition of ZrO2 nanoparticles.[15]

The limitations of this study must be noted. In vitro studies could not exactly act out like oral environs. Other limitation of this study is a limited sample size.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 

  References 
1.Im SM, Huh YH, Cho LR, Park CJ. Comparison of the fracture resistances of glass fiber mesh- and metal mesh-reinforced maxillary complete denture under dynamic fatigue loading. J Adv Prosthodont 2017;9:22-30.  
    2.Alla R, Raghavendra K, Vyas R, Konakanchi A. Conventional and contemporary polymers for the fabrication of denture prosthesis: part I-overview, composition and properties. Int J Appl Dent Sci 2015;1:82-9.  
    3.Pan Y, Liu F, Xu D, Jiang X, Yu H, Zhu M. Novel acrylic resin denture base with enhanced mechanical properties by the incorporation of PMMA-modified hydroxyapatite. Prog Nat Science: Mater Int 2013;23:89-93.  
    4.Bettencourt AF, Neves CB, de Almeida MS et al. Biodegradation of acrylic based resins: a review. Dental materials 2010;26:e171-e180.  
    5.Nejatian T, Johnson A, Van Noort R. Reinforcement of denture base resin. Trans Tech Publ 2006; 124-9.  
    6.Rashad HA, Abutaleb FA. Effect of Nano silver as additive by different ways to acrylic denture base and its role in menopausal woman management. Egypt Dent J 2018;64:1513-22.  
    7.Lee B, Kwon J-S., Khalid MW et al. Boron nitride nanoplatelets as reinforcement material for dental ceramics. Dent Mater 2020;36:744-54.  
    8.Bohns FR, Degrazia FW, de Souza Balbinot G et al. Boron nitride nanotubes as filler for resin-based dental sealants. Sci Rep 2019;9:1-8.  
    9.Degrazia FW, Leitune VCB, Visioli F, Samuel SMW, Collares FM. Long-term stability of dental adhesive incorporated by boron nitride nanotubes. Dent Mater 2018;34:427-433.  
    10.Degrazia FW, Leitune VCB, Samuel SMW, Collares FM. Boron nitride nanotubes as novel fillers for improving the properties of dental adhesives. J Dentistry 2017;62:85-90.  
    11.Özmeriç N, Çakal GÖ, Gökmenoğlu C et al. Histomorphometric and biomechanical evaluation of the osseointegration around micro- and nano-level boron-nitride coated titanium dental implants. J Stomatol Oral Maxillofac Surg 2022;123:e694-e700.  
    12.Alansy AS, Saeed TA, Al-Attab R et al. Boron nitride nanosheets modified with zinc oxide nanoparticles as novel fillers of dental resin composite. Dental Materials. 2022;38:e266-74.  
    13.Council on Dental Materials I, Equipment. American National Standards Institute/American Dental Association Specification No. 61 for zinc polycarboxylate cement. J. Am. Dent. Assoc. 1980;101:669-71.  
    14.Ghaffari T, Hamedirad F, Ezzati B. In vitro comparison of compressive and tensile strengths ofacrylic resins reinforced by silver nanoparticles at 2% and0.2% concentrations. J Dent Res Dent Clin Dent Prospects 2014;8:204-9.  
    15.Ihab N, Moudhaffar M. Evaluation the effect of modified nano-fillers addition on some properties of heat cured acrylic denture base material. J Baghdad Coll Dent 2011;23:23-29.  
    16.Oleiwi JK, Hamad QA. Studying the mechanical properties of denture base materials fabricated from polymer composite materials. Al-Khwarizmi Eng J 2018;14:100-11.  
    17.Alqahtani M. Effect of hexagonal boron nitride nanopowder reinforcement and mixing methods on physical and mechanical properties of self-cured PMMA for dental applications. Materials 2020;13:2323.  
    18.Alqahtani M. Mechanical properties enhancement of self-cured PMMA reinforced with zirconia and boron nitride nanopowders for high-performance dental materials. J Mech Behav Biomed Mater 2020;110:103937.  
    19.Kamil AS, Al-Judy HJ. Effect of addition of silanized silicon carbide nanoparticles on some physical properties of heat cured acrylic denture base material. J Res Med Dent Sci 2018;6:86-95.  
    20.Alwan SA, Alameer SS. The effect of the addition of silanized Nano titania fillers on some physical and mechanical properties of heat cured acrylic denture base materials. J Baghdad Coll Dent 2015;325:1-12.  
    21.Gantz L, Fauxpoint G, Arntz Y, Pelletier H, Etienne O. In vitro comparison of the surface roughness of polymethyl methacrylate and bis-acrylic resins for interim restorations before and after polishing. J Prosthetic Dent 2021;125:833.e1-e10.  
    22.Mangal U, Kim J-Y, Seo J-Y, Kwon J-S, Choi S-H. Novel poly (methyl methacrylate) containing nanodiamond to improve the mechanical properties and fungal resistance. Mater 2019;12:3438.  
    23.Ahmed AG, Ismail IJ. Evaluation the effect of addition of plasma treated polypropylene fiber and silanized silicon dioxide nanoparticles composite on some properties of heat-polymerized polymethylmethacrylate. J Baghdad Coll Dent 2016;28:1-8.  
    
  [Figure 1]