UNIVERSIDADE ESTADUAL PAULISTA
“JÚLIO DE MESQUITA FILHO”
Instituto de Ciência e Tecnologia
Campus de São José dos Campos
ORIGINAL ARTICLE DOI: https://doi.org/10.4322/bds.2024.e4201
1
Braz Dent Sci 2024 Apr/June;27 (2): e4201
This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited.
The effect of ZnO nanoparticles addition to PMMA on surface
contact angle and adhesion of
Candida albicans
O efeito da adição de nanopartículas de ZnO ao PMMA no ângulo de contato superficial e na adesão de
Candida albicans
Dedi FARDIAZ1 , Dyah IRNAWATI2 , NURYONO3
1 - Universitas Gadjah Mada, Magister Dental Science Study Program, Faculty of Dentistry, Yogyakarta, Indonesia.
2 - Universitas Gadjah Mada, Department of Dental Biomaterials, Faculty of Dentistry, Yogyakarta, Indonesia.
3 - Universitas Gadjah Mada, Department of Chemistry, Faculty of Mathematics and Natural Sciences, Yogyakarta, Indonesia.
How to cite: Fardiaz D, Irnawati D, Nuryono. The effect of ZnO nanoparticles addition to PMMA on surface contact angle and adhesion
of
Candida albicans
. Braz Dent Sci. 2024;27(2):e4201. https://doi.org/10.4322/bds.2024.e4201
ABSTRACT
Background: Heat polymerized polymethyl methacrylate resin (PMMA) is a porous denture material prone
to microbial attachment due to water absorption.
Candida albicans
(
C. albicans
) in PMMA can cause denture
stomatitis. Zinc Oxide Nanoparticles (ZnO NPs) possess antimicrobial properties. Objectives: This study aimed
to investigate the effect of adding various concentrations of ZnO NPs to PMMA on surface contact angle and
C. albicans
adhesion. Material and Methods: The PMMA samples (10x10x2mm) were prepared with ZnO
NPs concentrations of 0%, 2.5%, 5%, and 7.5% (n=4). The samples were soaked in distilled water 48 hours at
37°C. The contact angle test was performed using drop-prole analysis.
C. albicans
adhesion test was evaluated
through the
3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide
(MTT assay) for cell viability. The
distribution prole of Zn element was observed using SEM-EDX. The release of Zn2+ was tested by analyzing the
aqueous solution after sample immersion AAS. Results: The mean contact angles (°): 82.96±4.20; 82.36±0.66;
86.25±4.49; and 92.82±5.40. Results of
post-hoc
LSD showing differences only in the 7.5% ZnO NPs group.
The mean viability
C. albicans
(%): 2.27±0.80; 1.55±0.50; 1.45±0.33; and 1.43±0.12. There was a tendency
of decreasing means with increasing concentrations. However, this trend was not consistent with
one-way
ANOVA, which indicated no signicant differences among the treatment groups. SEM-EDX demonstrated ZnO
NPs distribution within PMMA’s matrix. AAS results revealed no Zn2+ presence in distilled water. Conclusion: In
conclusion, the addition of ZnO NPs to PMMA results in an increased contact angle, while exhibiting a statistically
non-signicant reduction in
C. albicans
adhesion.
KEYWORDS
C.albicans
; Contact angle; Nanoparticles; PMMA; ZnO.
RESUMO
Introdução: A resina de polimetilmetacrilato polimerizada termicamente (PMMA) é um material poroso para
próteses propenso à xação microbiana devido à absorção de água.
Candida albicans
(
C. albicans
) no PMMA pode
causar estomatite protética. Nanopartículas de óxido de zinco (NPs de ZnO) possuem propriedades antimicrobianas.
Objetivos: Este estudo teve como objetivo investigar o efeito da adição de várias concentrações de NPs de ZnO ao
PMMA no ângulo de contato da superfície e na adesão de
C. albicans
. Material e Métodos: As amostras de PMMA
(10x10x2mm) foram preparadas com concentrações de NPs de ZnO de 0%, 2,5%, 5% e 7,5% (n=4). As amostras
foram embebidas em água destilada por 48 horas a 37ºC. O teste do ângulo de contato foi realizado utilizando
análise de perl de gota. O teste de adesão de
C. albicans
foi avaliado através do brometo de 3-(4,5-dimetil-2-
tiazolil)-2,5-difenil-2H-tetrazólio (ensaio MTT) para viabilidade celular. O perl de distribuição do elemento Zn
foi observado utilizando MEV-EDS. A liberação de Zn2+ foi testada analisando a solução aquosa, após imersão da
amostra, por AAS. Resultados: As médias dos ângulos de contato (º): 82,96±4,20; 82,36±0,66; 86,25±4,49; e
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Fardiaz D et al.
The effect of ZnO nanoparticles addition PMMA on surface contact angle and adhesion of Candida albicans
Fardiaz D et al. The effect of ZnO nanoparticles addition PMMA on surface
contact angle and adhesion of Candida albicans
INTRODUCTION
Tooth loss become an oral health problem
in Indonesia with the highest prevalence of
sufferers among people aged 45-65 years.
The basic health research at 2018 stated that
the prevalence of patients in the age range of
45-54 years was 23.6%; 55-64 years was 29%;
and over 65 years was 30%. Treatment in the
form of making dentures is needed to overcome
problems related to tooth loss [1]. Dentures are
divided into xed and removable dentures, and
removable dentures is preferred by majority of
patients [2]. A removable denture consists of base
structure, clasps and articial teeth. The denture
base is the part of the denture that rests on the
supporting tissue, which articial teeth and clasps
are attached [3].
Polymer dentures are the most commonly
used material which is easy to manipulate,
lightweight, stable in the oral cavity, and
more esthetics than the other materials [4].
Polymer denture bases are classied based on
their polymerization method, including cold
polymerized acrylic resin, light polymerized
acrylic resin and heat polymerized acrylic resin.
Polymethyl methacrylate (PMMA) is a types
of acrylic resin that often used due to its good
biocompatibility, color and texture resembling
gingiva, good dimensional stability, relatively low
water absorption and ease of manipulation [3].
Aside from its advantages, PMMA has a
porous surface and tends to absorb water through
an imbibition process so that it is easily attached
by microorganisms [5]. According to research by
Gad et al. [6] porous surfaces can become sites
for adhesion and colonization of microorganism
thereby affecting the health of the oral cavity,
and triggering denture stomatitis.
Candida
albicans
is capable of adhering to the PMMA
surface through the formation of biofilm [7].
The formation of biolm and bacterial growth
on the PMMA surface that is already in the
oral cavity, can affect the general condition of
denture users [8]. Microorganism infection in
the oral cavity can cause tooth decay, periodontal
disease, and denture stomatitis due to
Candida
growth [9]. Early infection process
of C. albicans
in denture wearers is the adhesion of the cell
wall layer to the surface through a combination
of specic (ligand and receptor) and non-specic
mechanisms (electrostatic poles and
van der
Waals
bonds
)
, negatively charged
Candida
cell
surface and positively charged acrylic resin
surface
,
mutual attraction occurs [10].
PMMA has a surface contact angle of 65o which
indicates a hydrophilic surface characteristic [11].
The hydrophilic surface has a high surface
energy causing extensive surface wettability
which makes it easier for the accumulation of
bacterial plaque [12]. The study of microbial
adherence involves a multifaceted analysis,
encompassing crucial parameters such as surface
contact angle, which inuences the interaction
dynamics between microorganisms and surfaces.
Investigating the structural morphology of
materials provides valuable insights into the
substrate’s topographical characteristics and its
impact on microbial adhesion [13]. The wide
surface wettability causes a water layer to form
immediately in the contact area between the
support and the physiological media so that the
extracellular matrix can be properly distributed
and the bacterial adhesion becomes strong [14].
A research study has been conducted to
impart antimicrobial properties to polymers,
including the addition of metal oxides such
as ZrO2, TiO2, SiO2, AI2O2 and ZnO [15,16].
The integration of metal oxides into PMMA to
serve as antimicrobial agents involves of llers.
Zinc Oxide Nanoparticles (ZnO NPs) represent
a specific category of materials capable of
enhancing the strength, tensile properties, and
92,82±5,40. Resultados do LSD post-hoc mostrou diferenças apenas no grupo de 7,5% de NPs de ZnO. A viabilidade
média de
C. albicans
(%): 2,27±0,80; 1,55±0,50; 1,45±0,33; e 1,43±0,12. Houve tendência de diminuição
das médias com o aumento das concentrações. No entanto, essa tendência não foi consistente com a ANOVA
unidirecional, que não indicou diferenças signicativas entre os grupos de tratamento. MEV-EDS demonstrou a
distribuição de NPs de ZnO dentro da matriz de PMMA. Os resultados da AAS não revelaram presença de Zn2+ na
água destilada. Conclusão: Em conclusão, a adição de NPs de ZnO ao PMMA resulta em um aumento do ângulo
de contato, ao mesmo tempo que exibe uma redução estatisticamente não signicativa na adesão de
C. albicans
.
PALAVRAS-CHAVE
C. albicans
; Ângulo de contato; Nanopartículas; PMMA; ZnO.
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The effect of ZnO nanoparticles addition PMMA on surface contact angle and adhesion of Candida albicans
Fardiaz D et al. The effect of ZnO nanoparticles addition to PMMA on surface
contact angle and adhesion of Candida albicans
imparting antimicrobial effects to denture bases
when incorporated into the PMMA matrix [17].
The size, shape, properties and bonds formed
between the ZnO NPs and the PMMA polymer
matrix can improve the mechanical properties and
antimicrobial effect. According to Hammani
et al
.
ZnO NPs can bind to the (-COOR) group of the
PMMA polymer during polymerization by forming
hydrogen bonds between the carbonyl group
(-C=O) and the hydroxyl group (-OH) [18]. These
bonds ll spaces between linear macromolecular
chains of PMMA polymer particles thereby
reducing porosity [19].
Several studies explore the potential
antimicrobial effect of ZnO NPs. Abdelghafar
et al
.
stated that ZnO NPs has antibiolm activity on
Staphylococcus aureus
at a concentration of
3-5% [20] . Research by Esposti
et al
. stated that
0.1 mg/μl ZnO NPs had the growth inhibition
of
Streptococcus mutans
[21]. Other than
that, the latest study on the potential of Zn as
antimicrobial in PPMA found that Zn is effective
against
Escherichia coli
and
S. aureus
[22].
Beside the use of ZnO to increase the strength
of PPMA, the study assessing the effect of ZnO
nanoparticles as additional material for PMMA
against microbes especially for
C. albicans
is
limited [23]. Therefore, this study was performed
to investigate the effect of various concentrations
of ZnO NPs to PMMA on surface contact angle
and
C. albicans
adhesion.
MATERIALS AND METHODS
This study is a true experimental study
conducted at the Integrated Research Laboratory
of Faculty of Dentistry Universitas Gadjah Mada,
Laboratorium Penelitian dan Pengujian Terpadu
Universitas Gadjah Mada and Laboratorium
Sentra Ilmu Hayati Universitas Brawijaya.
This study received ethical clearance from the
Ethical Commission of the Faculty of Dentistry
- Universitas Gadjah Mada (UGM) under letter
number 0057/KKEP/FKG-UGM/EC/2022.
Samples preparation
The concentration of ZnO NPs added in
heat cured PMMA were 0%, 2.5%, 5%, and 7.5%
based on previous research by Cierech et al. [23].
The composition of each gorup was presented in
Table I. The samples with dimension 10 x 10 x
2 mm were made and the number of samples for
each group were 4 samples.
The PMMA (ADM, England) and ZnO NPs
(Sigma-Aldrich, USA) powder was put in the
stellon pot and mixed with crownmess until
homogeneous. The PMMA monomer liquid was
added into the stellon pot, stirred, then closed
until it reached the dough phase. The dough was
put into the cuvette, pressed, then polymerized in
curing units (Leleux Polypol Junior, Netherlands)
at 74oC for 1 hour and 90oC for 30 minutes
.
After that, the samples were cooled to room
temperature and the samples were deasked.
The PMMA prole analysis and distribution
of Zn
The Zn elements in the PMMA surface were
observed using Scanning Electron Microscope
Energy Dispersive X-ray (SEM-EDX) (JED-
2300, USA). The samples were tested under the
following conditions: 6510 (LA), volts: 15.00 kV,
and pixels:1024 x 768.
The form of mass and atomic percentages
were observed.
The Zn ion release test
The Zn2+ ions release were analyzed using
Atom Absorption Spectrophotometer (AAS)
(Perkin- Elmer 3110, USA). The samples were
immersed in 10 ml distilled water for 48 hours
at 37oC, then the sample solutions were analyzed
Table I - Study groups and material composition of PMMA and ZnO NPS
Groups
PMMA ZnO NPS
powder
(grams)
Total weight of
acrylic (grams)
Zn
Concentration (%)
Polymer
(grams)
Monomers
(mL)
1 20 10 0 30 0
2 20 10 0.769 30.769 2.5
3 20 10 1.578 31.578 5
4 20 10 2.432 32.432 7.5
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The effect of ZnO nanoparticles addition PMMA on surface contact angle and adhesion of Candida albicans
Fardiaz D et al. The effect of ZnO nanoparticles addition to PMMA on surface
contact angle and adhesion of Candida albicans
using AAS to detect the Zn2+ ions released.
The results of ZnO NP analysis on standard
blanks serve as the starting point for the results
of the sample solution to be tested and the
concentrations were calculated in ppm.
Contact angle test
The contact angle test was conducted by
drop-prole analysis technique based on Yulianto
and Rinastiti method [24]. The sample was placed
in front of the camera (Nikon, Japan), then the
distilled water was dripped using a 6 microliter
micropipette perpendicular to the sample surface.
After 10 seconds, the equilibrium between the
liquid and the sample surface. The image was
taken with the camera and transferred to the
ImageJ software on the computer to identify the
line interaction between the liquid surface and
the sample surface, indicated by the formation of
an angle where the magnitude can be measured
in degrees (o).
C. albicans
adhesion test
The
C. albicans
adhesion test consisted of
four groups, with different concentrations, four
independent assays were conducted for each
group.
C. albicans
adhesion test followed the
procedure described by Ghosemi et al. [25].
C. albicans
suspension was prepared at a
concentration of 106 CFU/mL in potato dextrose
broth medium
.
Adhesion of
C. albicans
on acrylic
resin samples was carried out by immersing
the samples in a suspension of
C. albicans
then
incubated at 30oC for 24 hours. The release of
C. albicans
into Saboraud broth was carried out
by placing the sample in a test tube containing
10 mL of Saboraud broth and then vibrating it
with thermolyne for 30 seconds. The released
C. albicans
was added to the potato dextrose
broth. Then it was put into the incubator shaker at
30oC for 60 minutes. The substrate was extracted
using
ethyl acetate
and thickened using
a rotary
evaporator.
The test was continued with the MTT
assay (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-
2H-tetrazolium bromide) on a 96-well microplate
and quantitative analysis was conducted to
determine cell viablity as a percentage (%).
Statistical analysis
Mean and standard deviation of all data were
calculated, except SEM EDX data. The contact
angle and
C. albicans
viability were analyzed
statistically using One Way ANOVA test with
Least Signicant Difference (LSD) post hoc test
with 95% condence level.
RESULTS
The contact angle test
Analysis of the aquadest contact angle on the
PMMA surface used the
sessile drop test
method,
and the results of the observations as a contact
angle measurement is presented in Figure 1.
The highest mean contact angle was found in the
7.5% ZnO NPs group, while the lowest contact
angle value was in the 2.5% ZnO NPs group
(Figure 2). The results of the contact angle test
Figure 1. (a) PMMA (b) PMMA + 2.5% ZnO NPs (c) PMMA + 5% ZnO NPs (d) PMMA + 7.5% ZnO NPs.
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The effect of ZnO nanoparticles addition PMMA on surface contact angle and adhesion of Candida albicans
Fardiaz D et al. The effect of ZnO nanoparticles addition to PMMA on surface
contact angle and adhesion of Candida albicans
showed the contact angle of aquadest tend to
increase on PMMA as the ZnO NP concentration
increased.
The results of the One-Way ANOVA showed
the F value 5.451 and the significance of the
test results 0.013, meaning that there was a
mean difference between the four groups of
ZnO NPs addition to the contact angle of water
on the PMMA surface (p<0.05). The value
obtained from the One-Way ANOVA meets the
requirements for a post-hoc test Least Signicant
Difference (LSD)0.05. The LSD test results have
been carried out with the results presented
in Table II. There is a signicant difference of
contact angle between 7.5% ZnO NPs group with
other groups (p<0.05).
Adhesion test of
C. albicans
Candida albicans
adhesion test was carried
out by calculating the percentage of cell viability
presented in Table III. The average value of
C. albicans
cell viability in PMMA showed that
with increasing ZnO NPs concentration there
was a tendency to decrease the number of cell
viability. The results of the one-way ANOVA test
can be seen in Table III. The results of the ANOVA
test showed the calculated F value 2.318 and the
signicance of the test results 0.127 which means
that there was no significant effect between
groups of ZnO NPs concentrations in PMMA on
C. albicans
cell viability (p>0.05).
PMMA prole analysis and distribution of Zn
The results of observations through SEM
revealed that there was an interaction between
ZnO NPs and PMMA showing a visual difference
in the pore prole of the PMMA surface. At a
concentration of 7.5% ZnO NPs it can be seen less
surface pores compared to other concentrations.
The addition of ZNO NP to PMMA produced a
denser surface and reduce the presence of pores
in PMMA. The observation results are presented
in Figure 3.
The elemental content of Zn in PMMA data
were presented in Table IV. The results of the
analysis obtained important information about
changes in the mass and atoms of Zn measured.
However, when the ZnO concentration was
Table II - LSD post hoc test results 0.05 contact angle test
Groups
1
0%
ZnO NPs
2
2.5%
ZnO NPs
3
5%
ZnO NPs
4
7.5%
ZnO NPs
1 (0% ZnONPs) - 0.60 3.28 9.86 *
2 (2.5% ZnO NPs) - - 3.88 10.46 *
3 (5% ZnONPs) - - - 6.57 *
4 (7.5% ZnO NPs) - - - -
Note: * = significant difference.
Table III - The mean value and standard deviation of
C. albicans
cell viability (%)
Group Mean and standard
deviation (%) p-Value
1 (0% ZnONPs) 2.27±0.80
0.127
2 (2.5% ZnO NPs) 1.55±0.50
3 (5% ZnONPs) 1.45±0.33
4 (7.5% ZnO NPs) 1.43±0.12
Figure 2. Mean and standard deviation of the contact angle test
(°). * Mean significan different with other groups. Table IV - Percentage of mass and atoms of Zn elements in PMMA (%)
Groups Zn period Zn atoms
1 (0% ZnO NPs) 0.00 0.00
2 (2.5% ZnO NPs) 3.24 0.67
3 (5% ZnO NPs) 3.31 0.68
4 (7.5% ZnO NPs) 19.69 4.67
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The effect of ZnO nanoparticles addition PMMA on surface contact angle and adhesion of Candida albicans
Fardiaz D et al. The effect of ZnO nanoparticles addition to PMMA on surface
contact angle and adhesion of Candida albicans
increased to 2.5%, 5%, and 7.5% there was
a significant increase in the mass and atomic
number of Zn. These results indicate that the
higher the concentration of ZnO in PMMA, the
more mass and Zn atoms are detected.
The 7.5% ZnO NP group showed a higher
mass and atomic number compared to the other
groups. This shows that increasing the ZnO
concentration has a signicant effect on increasing
the mass and number of Zn atoms in PMMA
matrix. Visual observation through a pattern of
dots that form a blue zone is presented in Figure 4.
Observations of Zn elements in PMMA show that
there are aggregations of particles scattered in
the PMMA matrix. The addition of 7.5% ZnO
NP to PMMA resulted in a more concentrated
Zn distribution pattern. Irregular image patterns
indicate that ZnO NP particles tend to gather in
certain areas, forming irregular formations.
The calculation of the absorbance value
in AAS showed the Zn element released from
PMMA. The data were presented in Table V.
Based on absorbance value in the sample it shows
a substandard value, this indicates that the Zn
was not detected in the solution tested.
DISCUSSION
In this study, the addition of ZnO NPs to
PMMA affects several aspects including contact
angle and
C. albicans
adhesion. The result showed
that contact angle tends to increase with the
concentration of ZnO NP. One-way ANOVA result
indicated a signicance level of 0.013, suggesting
a signicant effect of ZnO NP concentration on
the contact angle of distilled water on the PMMA
surface (p <0.05). The results of this study are in
accordance with the hypothesis which states that
there is an effect of the addition of ZnO NP on
the contact angle of distilled water on the PMMA
surface. An increase in the contact angle indicates
a change in surface properties to become more
hydrophobic [20]. The increase in hydrophobicity
Figure 3. Analysis SEM on PMMA. (a). 0% ZnO NPs (b). 2.5% ZnO NPs (c). 5% ZnO NPs(d). 7.5% ZnO NPs.
Table V - The mean value and standard deviation of the absorbance
in the AAS test
Groups Mean and Standard Deviation
1 (0% ZnO NPs) 0.042 ± 0.0092
2 (2.5% ZnO NPs) 0.047 ± 0.014
3 (5% ZnO NPs) 0.048 ± 0.010
4 (7.5% ZnO NPs) 0.049 ± 0.012
Note: Standard 1 (0.1 mg/L) = 0.055.
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The effect of ZnO nanoparticles addition PMMA on surface contact angle and adhesion of Candida albicans
Fardiaz D et al. The effect of ZnO nanoparticles addition to PMMA on surface
contact angle and adhesion of Candida albicans
occurs due to the addition of ZnO NPs which may
change the morphology and surface properties of
the acrylic resin. ZnO particles have hydrophobic
properties so that when mixed with acrylic resin,
they will form a barrier structure between the
resin surface and water or other polar liquids,
thereby reducing the interaction between water
and the substrate surface [26,27].
Research by Saputra
et al
. stated that ZnO
NP has a small particle size so that it can close
the matrix gap [28]. The results of research
conducted by Shanan
et al
. stated that ZnO NPs
can bond with PMMA polymers through covalent
bonds, forming a layer that can change the surface
properties to become more hydrophobic [27].
This layer is a barrier between PMMA and
aquadest. Research conducted by Esposti
et al
.
stated that the deposition of microorganisms on
PMMA is difcult to occur on surfaces that have
low wettability [21]
.
Hwang
et al
., stated that
on a hydrophilic surface, the surface tends to
be moist and can provide a good environment
for bacterial growth, whereas on a hydrophobic
surface it tends to be dry and makes it difcult for
bacterial growth so that it can be used to reduce
or prevent bacterial growth [29].
C. albicans
adhesion test showed that ZnO
NP has a tendency to decrease the number
of cell viability. ZnO NP 7.5% reduce the cell
viability from 2.27% (0% ZnO NP group) to
1.45%. The one-way ANOVA results showed
a signicance test value of 0.127, indicating
that the observed changes did not reach the
level of statistical signicance. Theoretically,
the interaction between ZnO NP particles and
C. albicans
adhesion occurs through several
mechanisms, including affect
C. albicans
cell
metabolism and cell growth. This can happen
due to ZnO NP properties that able to inhibit
the activity of the cell growth enzyme, glucose-
6-phosphate dehydrogenase [30]. ZnO NP can
form a hydrophobic layer on the PMMA surface
which can inhibit the interaction between
C. albicans
and PMMA. This is result in the
reduction in cell viability due to decrease in cell
growth [25].
Figure 4. Distribution of Zn in PMMA. (a). PMMA (b). PMMA + 2.5% ZnO NPs (c). PMMA + 5% ZnO NPs (d). PMMA + 7.5% ZnO NPs. Yellow
arrow: Zn.
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The effect of ZnO nanoparticles addition PMMA on surface contact angle and adhesion of Candida albicans
Fardiaz D et al. The effect of ZnO nanoparticles addition to PMMA on surface
contact angle and adhesion of Candida albicans
The SEM analysis indicated Zn elements
in the PMMA matrix. The surface of PMMA
which was supplemented with ZnO NP looked
less porous than that which was not added ZnO
NP. This is in line with research conducted by
Cierech
et al
. that ZnO NP has a role in lling
the assembly gaps in the PMMA matrix, so that
the surface is atter [13]. The distribution of Zn
elements visually presented in Figure 3 shows
that higher ZnO NP concentration in PMMA,
show more blue dotted zones. It can be seen that
the blue dots join together to form an irregular
formation. This indicates that the ZnO particles
are experiencing agglomeration (clustering).
The addition of 7.5% ZnO NP to PMMA causes
particle aggregation which forms a collection of
particles and is not evenly dispersed in the PMMA
matrix. Tanase
et al
. stated that particles that have
mass and are small in size can easily agglomerate
to form irregular formations [31]. The occurrence
of particle agglomeration, can cause a decrease in
physical properties, antimicrobial properties, and
a decrease in the level of transparency. Apip
et al
.
stated that the antimicrobial power of ZnO NPs
could be inhibited due to aggregation in the
PMMA matrix [32].
The Atomic Absorption Spectrophotometer
(AAS) test has been carried out in PMMA
immersion. The test results showed that Zn2+
ions were not detected in the aquadest bath. This
indicates that the Zn element was not detected
in the tested solution, thereby ruling out the
possibility of elemental release causing the
formation of gaps or pores in the polymer matrix.
The parameter in understanding the
interaction between the surface of the material and
microorganisms is through the zeta potential. In this
study, modication of the PMMA matrix through
the addition of ZnO NP and its effect on
C. albicans
adhesion made it possible for a difference in
electrical potential between the surface of the
material and the cell wall
of C. albicans.
These
differences result in cell adhesion to the surface of
the material cannot occur. Zore
et al
. stated that
the bacterial cell wall interacts with the surface
of the material, zeta potential being an important
factor in determining the adhesion or rejection
between the two entities [33]. If the zeta potential
between the bacterial cell wall and the surface of
the material has the same value or is close to zero,
then adhesion will occur due to the attractive force
between them. However, if the zeta potential has
a high value (positive or negative), the particles
will repel each other, thereby inhibiting bacterial
adhesion and
C. albicans
biolm growth. In this
study, the addition of ZnO NP show a decrease
of
C. albicans
viability and expected to give an
impactful insight in PMMA synthesis.
There are some limitations related to this
study. The study used a relatively small sample
size, four replications for each group. A larger
sample size could provide more statistically
robust results and better represent the denture
user population. The samples were soaked in
distilled water for 48 hours. This duration may
not fully simulate the long-term conditions that
dentures are exposed to within the oral cavity.
Prolonged immersion times could yield different
results. The study’s methodology did not consider
dynamic factors, such as the movement of the oral
cavity and the presence of saliva, which can affect
microbial adhesion and surface characteristics
of denture materials. The study acknowledges
the complex interaction between ZnO NPs and
PMMA. The exact mechanisms and influence
of various factors need further investigation.
The study also did not extensively characterize
the ZnO NPs used, including aspects such as
particle size, shape, and surface properties.
Further study analyzing size and distribution
of ZnO nanoparticle is required to obtain the
supporing data related the application of ZnO
in the heat polymerized acrylic resin. The safety
and biocompatibility of ZnO NPs in dental
applications are essential, considerations and
require further investigation.
On the other hand, this preclinical study
provides some potential for the future studies.
In this study we only focused solely on the
adhesion of
C. albicans.
In real-life situations,
the oral cavity harbors various microorganisms,
and their interactions with denture materials may
differ. This study methods then can be used in the
other study involving various microorganisms.
The study was conducted in a controlled
laboratory setting. Clinical studies involving
denture wearers could provide insights into
the practical implications of ZnO NP-modied
dentures. The study focused on PMMA. Denture
materials can vary widely, and the interaction
of ZnO NPs with different materials should be
explored. This study also can be an initiation
to establish studies asses the use of ZnO NP
by considering potential variations in denture
user populations based on factors like ethnicity,
age, and overall health. Further research and
9
Braz Dent Sci 2024 Apr/June;27 (2): e4201
Fardiaz D et al.
The effect of ZnO nanoparticles addition PMMA on surface contact angle and adhesion of Candida albicans
Fardiaz D et al. The effect of ZnO nanoparticles addition to PMMA on surface
contact angle and adhesion of Candida albicans
ne-tuning of parameters may unlock their full
potential in reducing microbial colonization.
The complexity of the interaction between ZnO
NPs and PMMA has been highlighted. The factors
inuencing this interaction, such as size, shape,
concentration, and environmental conditions,
need further exploration. This emphasizes the
need for continued research in this area.
CONCLUSIONS
The addition of ZnO NPs resulted in an
increased contact angle, indicating improved
hydrophobicity. This change in surface properties
may reduce water absorption, potentially
enhancing the durability of PMMA dentures and
minimizing the risk of microbial colonization.
While we observed a trend of decreasing
C. albicans
adhesion with increasing concentrations of ZnO
NPs, our statistical analysis indicated that this
reduction was not significant. However, the
non-significant reduction in adhesion is still
noteworthy, as it suggests that ZnO NPs could
potentially contribute to a decrease in denture
stomatitis cases. ZnO NPs are known for their
antimicrobial properties. While the study did
not show a signicant reduction in
C. albicans
adhesion, the antimicrobial characteristics of ZnO
NPs remain promising.
Author’s Contributions
DF: Conceptualization, Software, Resources,
Investigation, Writing – Original Draft Preparation,
Visualization. DI: Conceptualization, Metodology,
Supervision, Writing – Review & Editing, Project
Administration and Funding Acquisition. N:
Validation, Data Curation, Formal Analysis,
Writing – Review & Editing, Supervision.
Conict of Interest
The authors have no proprietary, nancial,
or other personal interest of any nature or kind
in any product, service, and/or company that is
presented in this article.
Funding
This research did not receive any specic
grant from funding agencies in the public,
commercial, or not-for-prot sectors.
Regulatory Statement
This study was conducted in accordance with
all the provisions from the Ethical Commission
of the Faculty of Dentistry - Universitas Gadjah
Mada (UGM) under letter number 0057/KKEP/
FKG-UGM/EC/2022.
REFERENCES
1. Badri IA. The relationship between the use of dentures and the
quality of life of the elderly in the Batu Aji Community Health
Center Working Area. J Smart Keperawatan. 2021;8:7-13. http://
doi.org/10.34310/jskp.v8i1.407.
2. Putri VS, Susanto HS, Hestiningsih R, Udijono A. The
relationship between maintenance behavior and the condition
of removable dentures in the community in the working area of
the Bandarharjo Community Health Center, Semarang City. J
Kesehat Masy. 2017;5:500-4.
3. Anusavice KJ, Shen C, Rawls HR. Phillips’ science of dental
materials. 12th ed. St. Louis Missouri: Elsevier Health Sciences;
2013.
4. Vikram S, Chander NG. Effect of zinc oxide nanoparticles on the
flexural strength of polymethylmethacrylate denture base
resin. Eur Oral Res
.
2020;54(1):31-5. http://doi.org/10.26650/
eor.20200063. PMID:32518908.
5. Sakaguchi R, Ferracane J, Powers J. Craig’s restorative dental
materials. St. Louis Missouri: Elsevier; 2019.
6. Gad MM, Abualsaud R, Fouda SM, Rahoma A, Al-Thobity AM,
Khan SQ,etal. Effects of denture cleansers on the flexural
strength of PMMA denture base resin modified with ZrO2
nanoparticles. J Prosthodont. 2021;30(3):235-44. http://doi.
org/10.1111/jopr.13234. PMid:32783226.
7. Silva MP, De Barros PP, Jorjão AL, Rossoni RD, Junqueira JC,
Jorge AO. Effects of Bacillus Subtilis on Candida Albicans: biofilm
formation, filamentation and gene expression. Braz Dent Sci.
2019;22(2):252-9. http://doi.org/10.14295/bds.2019.v22i2.1692.
8. Zafar MS, Ullah R. Phenolic compound-derived natural
antimicrobials are less effective in dental biofilm control
compared to chlorhexidine. J Evid Based Dent Pract.
2021;21(2):101576. http://doi.org/10.1016/j.jebdp.2021.101576.
PMid:34391562.
9. Bajunaid SO. How effective are antimicrobial agents on
preventing the adhesion of candida albicans to denture base
acrylic resin materials? A systematic review. Polymers (Basel).
2022;14(5):908. http://doi.org/10.3390/polym14050908.
PMid:35267731.
10. Dentino AR, Lee D, Dentino K, Guentsch A, Tahriri M. Inhibition
of
Candida albicans
and mixed salivary bacterial biofilms on
antimicrobial loaded phosphated poly(methyl methacrylate).
Antibiotics (Basel). 2021;10(4):427. http://doi.org/10.3390/
antibiotics10040427. PMid:33924304.
11. Wagner WR, Sakiyama-Elbert SE, Zhang G, Yaszemski MJ.
Biomaterials science: an introduction to materials in medicine.
4th ed. London: Academic Press; 2020.
12. Atalay S, Çakmak G, Fonseca M, Schimmel M, Yilmaz B. Effect of
thermocycling on the surface properties of CAD-CAM denture
base materials after different surface treatments. J Mech
Behav Biomed Mater. 2021;121:104646. http://doi.org/10.1016/j.
jmbbm.2021.104646. PMid:34166873.
13. Cierech M, Osica I, Kolenda A, Wojnarowicz J, Szmigiel D,
Łojkowski W,etal. Mechanical and physicochemical properties
of newly formed ZnO-PMMA nanocomposites for denture bases.
10
Braz Dent Sci 2024 Apr/June;27 (2): e4201
Fardiaz D et al.
The effect of ZnO nanoparticles addition PMMA on surface contact angle and adhesion of Candida albicans
Fardiaz D et al. The effect of ZnO nanoparticles addition to PMMA on surface
contact angle and adhesion of Candida albicans
Nanomaterials (Basel). 2018;8(5):305. http://doi.org/10.3390/
nano8050305. PMid:29734781.
14. Azmy E, Alkholy MR, Helal MA. Microbiological evaluation for
antifungal activity of some metal oxides nanofillers incorporated
into cold cured soft lining materials: clinical based study. Braz
Dent Sci. 2022;25(1):e2921. http://doi.org/10.4322/bds.2022.
e2921.
15. Helal MA, Yang B, Saad E, Abas M, Al-kholy MR, Imam AY,etal.
Effect of Sio2 and Al2o3 nanoparticles on wear resistance of
PMMA acrylic denture teeth. Braz Dent Sci. 2020;3(3):1-12.
http://doi.org/10.14295/bds.2020.v23i3.1999.
16. Kukulka EC, Souza JR, Santos JD, Campos TM, Borges AL. Analysis
of the association of parameters in the formation of ultrafine fibers
from PEI and PMMA. Braz Dent Sci. 2021;24(3):1-7. https://doi.
org/10.14295/bds.2021.v24i3.2367.
17. Cierech M, Kolenda A, Grudniak AM, Wojnarowicz J, Woźniak
B, Gołaś M, et al. Significance of polymethylmethacrylate
(PMMA) modification by zinc oxide nanoparticles for fungal
biofilm formation. Int J Pharm. 2016;510(1):323-35. http://doi.
org/10.1016/j.ijpharm.2016.06.052. PMid:27346417.
18. Hammani S, Daikhi S, Bechelany M, Barhoum A. Role of ZnO
nanoparticles loading in modifying the morphological, optical,
and thermal properties of immiscible polymer (PMMA/PEG)
blends. Materials (Basel). 2022;15(23):8453. http://doi.
org/10.3390/ma15238453. PMid:36499948.
19. Youssef A, El-Nagar I. Preparation and characterization of
PMMA nanocomposites based on Zno-Nps for antibacterial
packaging applications. In: Proceedings of the 5th World
Congress on New Technologies (NewTech’19); 2019; Lisbon,
Portugal. Lisbon, Portugal; 2019. p. 105-1-13. http://doi.
org/10.11159/icnfa19.105.
20. Abdelghafar A, Yousef N, Askoura M. Zinc oxide nanoparticles
reduce biofilm formation, synergize antibiotics action and
attenuate Staphylococcus aureus virulence in host; an important
message to clinicians. BMC Microbiol. 2022;22(1):244. http://
doi.org/10.1186/s12866-022-02658-z. PMid:36221053.
21. Esposti MD, Fabbri P, Morselli D. Self‐assembled PMMA
porous membranes decorated with in situ synthesized
ZnO nanoparticles with UV‐tunable wettability. Macromol
Mater Eng. 2020;305(6):2000017. http://doi.org/10.1002/
mame.202000017.
22. Khlifi K, Atallah MS, Cherif I, Karkouch I, Barhoumi N, Attia-Essaies
S. Synthesis of ZnO nanoparticles and study of their influence
on the mechanical properties and antibacterial. Surf Interfaces.
2023;41:103279. http://doi.org/10.1016/j.surfin.2023.103279.
23. Cierech M, Wojnarowicz J, Kolenda A, Krawczyk-Balska
A, Prochwicz E, Woźniak B,etal. Zinc oxide nanoparticles
cytotoxicity and release from newly formed PMMA–zno
nanocomposites designed for denture bases. Nanomaterials
(Basel). 2019;9(9):1318. http://doi.org/10.3390/nano9091318.
PMid:31540147.
24. Yulianto HDK, Rinastiti M. Contact angle measurement of dental
restorative materials by drop profile image analysis. Jurnal
Teknosains. Jurnal Ilmiah Sains Dan Teknologi. 2014;3:2:112-9.
25. Ghosemi M, Turnbull T, Sebastian S, Kempson I. The MTT assay:
utility, limitations, pitfalls, and interpretation in bulk and
single-cell analysis. Int J Mol Sci. 2021;22(23):12827. http://doi.
org/10.3390/ijms222312827. PMID:34884632.
26. Singh A, Singh M, Pandey A, Ullas AV, Mishra S. Hydrophobicity
of cotton fabric treated with plant extract, TiO2 nanoparticles
and beeswax. Mater Today Proc. 2023;80:1530-3. http://doi.
org/10.1016/j.matpr.2023.01.353.
27. Shanan ZJ, Abdalameer NK, Ali HMJ. NK Abdalameer MK, Ali
HMJ. Zinc oxide nanoparticle properties and antimicrobial
activity. Int J Nanosci. 2022;21(03):2250017. http://doi.
org/10.1142/S0219581X2250017X.
28. Saputra W, Hartiati A, Harsojuwono BA. Pengaruh konsentrasi
seng oksida (ZnO) dan penambahan gliserol terhadap
karakteristik bioplastik dari pati umbi gadung (
Dioscorea hispida
Deenst). J Rekayasa Manaj Agroindustri. 2019;7(4):531-40.
http://doi.org/10.24843/JRMA.2019.v07.i04.p05.
29. Hwang J-J, Wu C-Y, Hung Y-H, Li M-X, Luo K-H, Jia H-W,etal.
Biomimetic PMMA coating surface and its application on
inhibition of bacterial attachment and anti-biofilm performance.
Surf Interfaces. 2023;36:102548. http://doi.org/10.1016/j.
surfin.2022.102548.
30. El-Samanody E-SA, El-Sawaf AK, Madkour M. Synthesis,
crystal structure, spectral and thermal investigations of
morpholinyldithiocarbamate complexes: A novel coordinated
precursors for efficient metal oxide nanophotocatalysts.
Inorg Chim Acta. 2019;487:307-15. http://doi.org/10.1016/j.
ica.2018.12.027.
31. Tănase MA, Marinescu M, Oancea P, Răducan A, Mihaescu
CL, Alexandrescu E, et al. Antibacterial and photocatalytic
properties of ZnO nanoparticles obtained from chemical versus
Saponaria officinalis
extract-mediated synthesis. Molecules.
2021;26(7):2072. http://doi.org/10.3390/molecules26072072.
PMid:33916520.
32. Apip C, Martínez A, Meléndrez M, Domínguez M, Marzialetti T,
Báez R,etal. An in vitro study on the inhibition and ultrastructural
alterations of
Candida albicans
biofilm by zinc oxide nanowires
in a PMMA matrix. Saudi Dent J. 2021;33(8):944-53. http://doi.
org/10.1016/j.sdentj.2021.08.006. PMid:34938036.
33. Zore A, Abram A, Učakar A, Godina I, Rojko F, Štukelj R,etal.
Antibacterial effect of polymethyl methacrylate resin base
containing TiO2 nanoparticles. Coatings. 2022;12(11):1757.
http://doi.org/10.3390/coatings12111757.
Dyah Irnawati
(Corresponding address)
Universitas Gadjah Mada, Department of Dental Biomaterials, Faculty of
Dentistry, Yogyakarta, Indonesia.
Email: dyahirnawati_fkg@ugm.ac.id
Date submitted: 2023 Dec 20
Accept submission: 2024 July 02
