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Volume 47, Number 1, March 2014

Research Report

The effect of soda immersion on nano hybrid composite resin 
discoloration

M. Chair Effendi,1 Yuli nugraeni2 and rizki Widya Pratiwi2
1 Department of Pediatric Dentistry, School of Dentistry Faculty of Medicine, Universitas Brawijaya 
2 Department of Conservative and Endodontic, School of Dentistry Faculty of Medicine, Universitas Brawijaya
Malang - Indonesia

abstract

Background: Composite resin is the tooth-colored restorative material which most of the people are fond of due to their aesthetic 
value. The composite resin discoloration may happen because of the intrinsic and extrinsic factors. Soda water is one of the beverages 
which can cause the composite resin discoloration. Purpose: The study was aimed to determine the effect of soda immersion on nano 
hybrid composite resin discoloration. Methods: The study was an experimental laboratory study using 100 shade A3 nano hybrid 
composite resin specimens with the diameter of 5 mm and density of 2mm. The samples were divided into 5 groups, each group was 
immersed in different beverages. The beverages were mineral water; lemon-flavored soda; strawberry-flavored soda; fruit punch-flavored 
soda; and orange-flavored soda for 3, 7, 14 and 21 days respectively, in the temperature of 37o C. The discoloration measurement 
utilizes Spectrophotometer, Vita Easy Shade, and uses CIEL*a*b* method. results: The result showed that the duration of immersion 
in soda had an effect on the Nano hybrid composite resin discoloration. Strawberry and fruit punch- flavored soda were the most 
influential components toward the discoloration. Nevertheless, the generally-occurred discoloration was clinically acceptable (∆E ≤ 
3,3). Conclusion: The study suggested that the soda immersion duration has effect on Nano hybrid composite resin discoloration. 

Key words: Nano hybrid composite, discoloration, soda beverages

abstrak

latar belakang: Resin komposit adalah material sewarna gigi yang diminati masyarakat karena memiliki nilai estetik yang baik. 
Perubahan warna resin komposit dapat terjadi karena faktor intrinsik dan ekstrinsik. Minuman soda merupakan salah satu minuman 
yang dapat menyebabkan perubahan warna pada resin komposit. tujuan: Tujuan dari penelitian ini untuk meneliti perubahan warna 
resin komposit nanohibrida akibat perendaman dalam minuman soda. Metode: Metode yang digunakan pada penelitian ini adalah 
eksperimental laboratorik dengan menggunakan 100 spesimen resin komposit nanohibrida shade A3 berdiameter 5 mm dan tebal 2 
mm. Sampel dibagi dalam 5 kelompok, masing-masing kelompok direndam dalam minuman yang berbeda, yaitu direndam dalam air 
mineral, soda lemon, soda strawberi, soda fruitpunch, dan soda jeruk selama 3, 7, 14 dan 21 hari, dalam suhu 37o C. Pengukuran 
perubahan warna menggunakan Spectrophotometer, Vita Easy Shade dengan metode CIEL*a*b*. hasil: Hasil penelitian menunjukkan 
bahwa lama perendaman pada minuman soda berpengaruh terhadap perubahan warna resin komposit nanohibrida. Soda yang paling 
berpengaruh terhadap perubahan warna adalah soda strawberi dan soda fruitpunch. Namun perubahan warna yang terjadi secara 
umum masih dapat diterima secara klinis (∆E ≤ 3,3). Simpulan: Hasil penelitian ini menunjukkan bahwa lamanya waktu perendaman 
mempengaruhi perubahan warna pada resin komposit nanohibrida. 

Kata kunci: Komposit nanohibrida, perubahan warna, minuman soda

Corespondence: M. Chair Effendi, c/o: Departemen Ilmu Kedokteran Gigi Anak, Program Studi Pendidikan Dokter Gigi. Universitas 
Brawijaya. Jl. Veteran Malang 65145, Indonesia. E-mail: chaireffendi@gmail.com



�8 Dent. J. (Maj. Ked. Gigi), Volume 47, Number 1, March 2014: 37–40

introduction

Soda is the carbonated water which has various 
flavorsand colors that can attract people to consume.1 

It is proven by American Academy of Pediatrics that 
reported 56-85% of students consume soda at least once 
a day. This percentage increases on teenage boys, 20% 
of them consume it at least four times a day.2 People’s 
habitto consume soda,which actually contains various dye 
substances, can affect the discoloration oftheir composite 
resinrestoration.3 In his previous experiment, Al- Shalan4 

proposed that there is composite resin discoloration after 
immersing intothe coffee, tea, and wine. It is supported 
by Chong et al.2 that consuming coffee, tea, soft drink 
(soda water), juice, and liquor may influence composite 
resin aesthetic and physical quality. Wan Bakar et al.5 

once noted that the discoloration may be caused by the 
absorption from staining substances such as wine, coffee, 
tea, and cola (soda).

Composite resin is the often used as restorative materials 
in dentistry due to its high aesthetic value. Composite resin 
are able to produce restoration color which is identical 
to original tooth color.5 Tyas6 reported the survey result 
toward 100 restoration users-55% use composite resins, 
28% use amalgam, 15% use GIC, and 2% use polyacid-
modified composite resin. Nano hybrid composite resin 
has better physical and mechanical value rather than the 
conventional composite resin. According to Al-Shalan,4 
nano hybrid composite resin have many advantages, that 
they can be used for anterior and posterior tooth restoration 
and reduce the shrinking during polymerization. Moreover, 
they also have smoother surface due to their nano particles, 
better mechanical and aesthetic quality, and they are also 
suitable for restoration on anterior teeth. As according to 
Wan Bakar et al.,5 the lack of composite resin is that their 
color is changed while exposed to other dye substances; 
whereas the most important roleof composite resin as 
the high aesthetic valued-restorationdepends on the color 
suitability among others.7

The discoloration may occur due to the intrinsic and 
extrinsic factors. The intrinsic factor derived from the 
composite resin it self, which occurs in the matrix resins 
or between the matrix gap and filler, while the extrinsic 
factor comes from plaque accumulation and staining 
caused by color substances penetration and exogenous 
contamination. The degree of exogenous discoloration is 
influenced by oral hygiene, food and beverages consumed, 
and smoking habit. Furthermore, discoloration may occur 
chemically, which relates to the alteration or oxidation on 
amine accelerator, oxidation of polymer matrix structure 
and methacrylate group.8

Soda not only contains dye substance but also contains 
sugar and has low pH. The sugar in it can increase the color 
change in composite resinrestoration material, while low pH 
(2.7) can influence the softening matrix in composite resin, 
so that it will affect on composite resin’s integrity.3 The 

existence of microcracks and microvoids between the filler 
and matrix resin can be the entrance for the dye substance to 
penetrate into the composite resin.4 Toksoy et al.9 supported 
that dye substance penetration causes the discoloration of 
composite resin from yellow to brownish.

More than 80% of patients are anxious about 
discoloration in the composite resin restoration they use. 
This discoloration is one of the reasons to replace the 
composite resin restoration. The previous study reported 
that the discoloration starts from the 1st up to the 2nd week 
since the composite resin is exposed to the beverages.4 

Nevertheless, the discoloration has not been examined 
up to the 3rd week. The study was aimed to determine the 
effect of soda immersion on nano hybrid composite resin 
discoloration.

materials and methods

This study was an experimental laboratory using 100 
plates of Nano hybrid composite resin mono ceram X 
dentsply® shade A3 which were immersed in mineral water 
and various kinds of flavored soda (lemon, strawberry, 
fruit punch, and orange) for 3, 7, 14 and 21 days in the 
temperature of 370 C. The discoloration is measured 
using CIEL *a*b method. The tool used to measure the 
discoloration was Vita Easy Shade Guide, which results in 
numbers to present the colors. Colors component measured 
were as follows: (1) L* or Lightness, the range of value 0 
(black) to 100 (white); (2) a* was a chroma component, 
which the discoloration was indicated by +a* to show 
reddish color and –a* to show greenish color; (3) b* was 
chroma component, which indicates +b* as yellowish and 
–b* as bluish.

The formula of discoloration:

∆E= {(∆L*)2+(∆a*)2+(∆b*)2}1/2

Note:
∆E : discoloration
∆L : black-white (L2 – L1)
∆a : color differences from red-green (a2 – a1)
∆b : color differences from yellow-blue (b2 – b1)

The straws were cut into 2 mm in height to make 
composite resin plates. After that, apply nano hybrid 
composite resin using plastic filling. Then, it was 
polymerized using the light cured for 20 seconds. All the 
specimens were immersed in distilled water for 24 hours 
in order to be perfectly polymerized in the temperature of  
370 C to stimulate the mouth cavity temperature. After being 
immersed by the distilled water, the specimens were dried 
with tissue. Then, the initial measurement was done to the 
composite resin using white paper as the base. Specimens 
were immersed in each flavored-beverages and mineral 
water for 3, 7, 14 and 21 days respectively. The flavored-



��Effendi, et al.: The effect of immersion in soda on nano hybrid composite resin discoloration

beverages (lemon, strawberry, orange, and fruit punch soda) 
were changed daily. Measure specimens’ colors on the 3rd, 
7th 14th and 21st day after the first immersion.

results

The effect of immersion duration toward the composite 
resin discoloration after being immersed in various colored 
and flavored soda was evaluated using statistical analysis 
repeated measures Anova with significance level of 0.05 
(p = 0,05) and confidence level of 95% (α = 0.05). The 
difference of nano hybrid composite resin discoloration 
due to the consumption of various colored and flavored 
soda water was evaluated using one way Anova statistical 
technique with significance level of 0.05 and confidence 
level of 95% (α = 0.05). The result of Repeates Measures 
Anova test showed that the significance level got from the 
calculating process was lesser than α = 0,05. So, it could be 
concluded that the duration of immersion in various colored 
and flavored soda water (mineral water, lemon, strawberry, 
fruit punch, and orange soda water) influences Nano hybrid 
composite resin discoloration significantly.

The result of one way Anova Test shows that the 
significance level obtained from the calculating process was 
less than α = 0,05. There was nano hybrid composite resin 
discoloration as the effect of consuming various colored 
and flavored soda. Strawberry and fruit punch- flavored 
soda were the most influential components toward the 
discoloration.

discussion

∆E* result on control group (immersed in mineral 
water) from days 3-21 indicates a range of value between 
0.62-1.36. The discoloration increases in accordance with 
immersion duration, yet the discoloration on the 14th and 
21st day did not differ significantly. It is corresponds to Al-
Shalan4 that the discoloration occurs from the first week of 
exposure and increases until the second week. ∆L* result 
on control group day 3 until 21 indicates the blackened 
composite resin which is marked by the decreasing of white 
spectrum (L*) degree during 21 days. The decreasing of 

color spectrum also occurs on ∆a* dan ∆b*. The immersion 
in mineral water only visually noticeable changes started 
from the 14th day, which is ∆E ≥ 1. Yet, it was still clinically 
acceptable. It is also happened in Fontes et al.10 that stated 
that after nano filler resin immersion in water for a week 
did not indicate any significant discoloration or it was 
still clinically acceptable. The discoloration may occur 
chemically related to the change or oxidation of amine 
accelerator, oxidation of polymer matrix structure, and 
oxidation of methacrylate group.

The immersion in lemon soda indicates an increase in 
discoloration (∆E*), which is in accordance with immersion 
duration. The increasing of discoloration in lemon soda 
indicates the different result among the other immersion 
group. Composite resin immersion in lemon soda causes 
an increase in degree of white color significantly (visually 
noticeable) begun on day 7 to 21 (∆L*= 1.05 – 1.79). It 
is due to the acid properties which have erosive effect 
to polymer material degradation and color pigment on 
composite resin (ferric oxide). 

The acid properties of soda water can dissolve 
polymer matrix of composite resin which causes white 
color appearance comes from silica powder contained 
in composite resin. Likewise in ∆a* dan ∆b*, there is 
an increase in accordance with immersion duration, the 
composite resin is heading to red and yellow. The range 
of composite resin discoloration caused by immersion in 
lemon soda is 0.62-1.79. The experiment result shows the 
quite significant discoloration in each immersion duration, 
however, the discoloration is small and still clinically 
acceptable (∆E ≤ 3.3).

The discoloration caused by strawberry soda can be 
seen	from	∆E	which	is	noticeable	on	3rd, 7th, 14th, and 
21st day with value range of 1.02-3.52. Color spectrum 
change that mostly affects ∆E value showed by ∆a* value 
(reddish) which is higher rather than ∆L* and ∆b* value 
from 1st until 21st day. This change indicates an increase 
of red spectrum degree which is caused by red pigment 
in strawberry soda. The Nano hybrid composite resin 
discoloration may berelatedto resin’ ability to absorb or 
adsorb color pigment in assorted soda colors and flavors.11 It 
is also concluded by Burrow and Makinson that composite 
resin discoloration is more visible due to absorption from 
colored-food rather than water. Based on the experiment 
result, there is a significant change in eachimmersion 
duration, yetthere are only 2 samples at the 21st day which 
the changes are clinically acceptable, which is more 
than clinically acceptable maximum criteria(∆E ≥ 3.3). 
Discoloration in strawberry soda is more than other soda 
water since it has very condensed color pigment. It can 
be proven from the left red stain in lips and tongue after 
consuming strawberry soda.

Nano hybrid composite resin discoloration range (∆E) 
after being immersed in fruit punch soda is 0.9-3.39. This 
discoloration ∆E* is highly influenced by ∆L*, ∆a*, dan 
∆b* values which continuously decrease after immersion. 
This condition indicates the discoloration proven by the 

figure 1. Graphic of discoloration.

water lemon soda strawberry
soda

fruitpunch
soda

orange 
soda

days

days

days

days



�0 Dent. J. (Maj. Ked. Gigi), Volume 47, Number 1, March 2014: 37–40

decreasing of white, red, and yellow spectrum degree in 
the Nano hybrid composite resin to the dark colors- green 
and blue. Based on the experiment, there is a still clinically 
acceptable significant discoloration of each immersion 
duration. There is only 1 sample at the 21st day which 
experiences discoloration more than 3.3. This is caused 
by the concentrated green pigment in fruit punch soda. It 
is proven by the left green stain in lips and tongue after 
consuming it. Generally, composite resin’s color stability 
is affected by various factors such as matrix resin, initiator 
concentration, oxidation of unreacted monomers, filler 
content, and pigment.11

Discoloration ∆E* in orange soda is tremendously 
affected by ∆L* value decreasing, while ∆a* dan ∆b* 
increase after immersion. This condition represents 
discoloration evidenced by degree decreasing of white 
spectrum and increasing of red and yellow spectrum in 
Nano hybrid composite resin specimens. Discoloration 
range on orange soda is 1.02-1.92. It can be known from 
the experiment that the discoloration is still clinically 
acceptable despite the significant discoloration of each 
immersion duration, which keep increasing during 3, 7, 
14 and 21 days.This change is caused by orange pigment 
in orange soda. It is concluded that the increasing of 
discoloration along with immersion duration indicates 
pigment exposure toward Nano hybrid composite resin, 
resulted on the clearer discoloration. 

All groups of composite resins immersed in assorted 
soda colors and flavors undergo quite significant 
discoloration in accordance with immersion duration. Still, 
commonly, the discoloration cannot be clinically accepted 
even though some samples immersed in strawberry and fruit 
punch show ∆E ≥ 3.3. The immersion in mineral water, 
lemon soda, orange soda, fruit punch soda, and strawberry 
soda indicates the discoloration sequences from the least 
to the most. Although nano hybrid composite resin has a 
good color stability, this experiment proves that there was 
a significant discoloration from the average value of ∆E* 
at 3rd until 21st day. Some researchers stated that ∆E* > 1 
in composite resin shows visually noticeable discoloration, 
however, up to ∆E* ≤ 3,3 can be clinically acceptable 

According to the experiment result, there is a significant 
discoloration along with nano hybrid composite resin 
immersion, yet this experiment indicates the smaller 
∆E* value than the previous experiment of Micro hybrid 
composite resins done by Toksoy Fulya in 2009. 

The study suggested that the soda immersion duration 
has effect on nano hybrid composite resin discoloration. 
However, the discoloration caused by immersion in 
lemon and orange soda is still clinically acceptable. Since 
soda can cause discoloration, the patients who are using 
composite resins are suggested not to consume too much 
soda water.

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