Kamla-Raj 2011

J Life Sci, 3(1): 29-33 (2011)

Evaluation of Microleakage of Various Restorative Materials:

An in Vitro Study
Kanika Verma Gupta1, Pradhuman Verma2 and Ashwarya Trivedi 3
1

Department of Pedodontics and Preventive Dentistry Desh Baghat Dental College and
Hospital, Muktsar, Punjab, India
2
Department of Oral Medicine and Radiology Desh Baghat Dental College and Hospital,
Muktsar, Punjab, India
3
Department of Oral Medicine and Radiology Guru Nanak Dev Dental College and Hospital,
Sunam, Punjab, India
KEYWORDS Microleakage. Glass Ionomer Cements. Composites. Compomer
ABSTRACT Microleakage is the clinically detectable passage of bacteria, fluids, molecules or ions between a
cavity wall and the restorative materials applied to it. The aim of this study was to evaluate and compare the
microleakage of six restorative materials viz., GC Fuji II LC, Ketac Molar Easy Mix, Filtek Z350, Filtek P60,
Durafill VS and Dyract Restorative. Sixty caries-free premolars were divided into six groups (n = 10) and standard
Class I cavities were restored with six different materials. Observation for marginal leakage was done under
Stereomicroscope at 10X and data collected was subjected to statistical analysis. Concluding from the study, the
sealing ability in terms of microleakage can be summarized as: Self-cured GIC (Ketac Molar Easy Mix) < Compomer
(Dyract) < Packable composite (Filtek P60) < Resin modified Glass ionomer cement (GC Fuji II LC) d Microfilled
composite (Durafill VS) < Nanocomposite (Filtek Z350).

INTRODUCTION
There have been more changes and developments in dentistry over the past decade than in
the previous hundred years combined, and the
pace is accelerating! In the current age of adhesive dentistry or microdentistry, conservation of
tooth structure is paramount. Rather than using
extension for prevention as a treatment guideline, emphasis now is placed on restriction with
conviction.
Microleakage is defined as the clinically detectable passage of bacteria, fluids, molecules or
ions between a cavity wall and the restorative
materials applied to it and is the major problem in
clinical dentistry. Achieving a micromechanical
and biomechanical bond between the restoration and tooth is considered effective and a standard procedure in clinical practice.
Instead of simply lathe-cut low copper amalgam or silicate cement, the menu of available
materials has expanded to include hybrid,
microfilled or optimal size particle, flowable or
packable composites, glass ionomers, resin reinforced glass ionomers and compomers in varying viscosities (Korkmaz et al. 2010).
The ultimate success of a material is indicated
by its longevity in the oral cavity. As the initial in
vitro screening of new materials does not always
reveal their full limitations or possibilities, clinical testing of new systems remains the ultimate

proof of effectiveness. In the oral cavity, multiple and mutually interactive clinical variables
related to tooth substrate and to its immediate
environment, co-determine the eventual clinical
effectiveness of newly developed adhesive materials as suggested by Hegde et al. (2009).
The objective of the present in vitro study,
is to compare the sealing ability of the most
innovative restorative materials being used in
clinical practice, including Conventional Glass
Ionomer Cements, Resin Modified GIC, Microfilled Composites, Packable Composites, Nanofilled Composites and Polyacid modified resin
composites (Compomer).
MATERIALS AND METHOD
This study was conducted in the Department
of Pedodontics and Preventive Dentistry, Guru
Nanak Dev Dental College and Research Institute, Sunam. Sixty caries-free maxillary and mandibular premolars, extracted for orthodontic
purposes were collected and used. The teeth
were examined by trans-illumination to exclude teeth exhibiting enamel fractures as these
might allow dye penetration. Calculus was removed with a scaler followed by cleaning with
pumice slurry (in water) and rubber prophylaxis cup. The teeth were stored in distilled water with few thymol crystals added to it.
Class I cavities standardized to a size of

30

KANIKA VERMA GUPTA, PRADHUMAN VERMA AND ASHWARYA TRIVEDI

3x2x2mm dimensions were prepared in each

sample with ISO Size (No.014) inverted cone and
(No.010) straight fissured diamond burs using
high speed water cooled hand piece.
Sixty samples were randomly divided into six
equal groups, Group I to Group VI, consisting of
10 samples of each group and were filled according to manufacturers instructions.
The samples were stored in distilled water
at room temperature for 24 hours and final finishing and polishing of the restorations was done
using fine finishing stones and polishing discs
(Sof-lex, 3M ESPE). The specimens were then
subjected to 1500 cycles of thermo-cycling between temperatures 12C 2 to 60C 2 with
dwell time of 30 seconds and 10 seconds interval between the baths.
Teeth were covered with yellow sticky wax to
occlude all the openings. Two coats of nail varnish were applied to all tooth surfaces except for
1mm around the restoration margins. The teeth
were subjected to the dye solution of 50 percent
Silver nitrate in small dark bottles for 4 hours and
kept away from light. Then, the specimens were
immersed in the photographic film developing
solution- for 4 hours under 200 watt bulb, keeping the light source as close as possible.
After the dye exposure, the teeth were thoroughly cleaned under running tap water for 5
minutes to remove the superficial dye and then
nail varnish was removed with the scalpel. Longitudinal sections were prepared with a Mandrel and diamond disk, in bucco-lingual direction, dividing the restoration at its midpoint
mesiodistally exposing the tooth interface from
cavosurface margin to the pulpal wall.
The degree of dye penetration in the occlusal
cavity walls was assessed separately under a
Binocular Stereomicroscope at 10X magnification. The part of the sectioned tooth which
showed more reading for microleakage was
considered in the study. The extent of dye penetration was determined at buccal and lingual/
palatal wall from the occlusal portion of the
restoration to base of the cavity along the tooth
restoration interface, by the following scoring
criteria given by Parbhakar et al. (2003).
0 : No dye penetration.
1 : Dye penetration between the restoration and
the tooth into enamel only.
2 : Dye penetration between the restoration and
the tooth in the enamel and dentin.

3: Dye penetration between the restoration and

the tooth into the pulp chamber.
The data collected was tabulated and subjected to statistical analysis to compare the
microleakage, using ANOVA and Unpaired t-test.
RESULTS
The mean microleakage scores of various restorative materials are depicted in Table 1. The
analysis of variance for microleakage for different restorative materials used in the study was
found to be significant (Table 2). The comparison of means of microleakage scores was done
at buccal and palatal/lingual walls for different
restorative materials used in study and it was
found that there was no statistically significant
difference obtained (Table 3). A significant difference was found in the microleakage values of
Group I (GIC Fuji II LC), group II (Ketac Molar
EM) and group VI (Dyract); whereas no significant difference of group I was found with other
groups. There was a significant difference (p <
0.05) in the microleakage of Group II with all the
other groups and the microleakage of Filtek Z350
(group III) was statistically significant with all
the groups except with Resin modified glass
ionomer cement (group I), Filtek P60 (group IV)
and Durafill (group V). Statistically significant
difference was found for microleakage scores of
Group IV with resin Group II and Group VI. There
was no significant difference in the microleakage
scores of Group V with other groups except with
Group II and Group V, whereas it was significant
for Group VI with all the groups. The comparison
of various different groups in their significance
is shown in Table 4.
Table 1: Mean values ( s.d) of microleakage for
various groups of restorative materials used in
the study
Group

Mean
(m)

Upper
value

Group I
Group II
Group III
Group IV
Group V
Group VI

0.4
2.75
0.05
0.55
0.35
1.45

2
3
1
3
3
3

Lower
value
0
2
0
0
0
0

S.D
0.753937
0.444262
0.223607
0.759155
0.74516
0.759155

It was observed from the obtained results

that, the advanced restorative material nanocomposite, Filtek Z350 displayed minimum microleakage while the microleakage of Self-cured

EVALUATION OF MICROLEAKAGE OF VARIOUS RESTORATIVE MATERIALS

Table 2: Analysis of variance for microleakage
for different restorative materials used in the
study
Source of
Degree Varia- p
Inference
variation
of free- nce
value
dom
ratio
(F)
Between group
Within group

5
54

47.15

31

and the best sealing quality (Fig. 4) was shown

by the Nanocomposite (Filtek Z350).

p < 0.05 Significant

Total
59
Analysis of variance for microleakage values with
different restorative materials used in the study
exhibited a significant relation (p < 0.05).
Table 3: Comparisons of means of microleakage
scores at buccal and palatal/lingual walls for
different restorative materials used in study
Groups

t value

p value

Significance

(Buccal :
Palatal/
Lingual Wall)
I
II
III
IV
V
VI

1.25
0.5
1.0
0.27
0.57
2.33

p
p
p
p
p
p

>
>
>
>
>
>

0.05
0.05
0.05
0.05
0.05
0.05

Not
Not
Not
Not
Not
Not

Fig. 1. Sample showing microleakage extending

into the pulp chamber

significant
significant
significant
significant
significant
significant

Table 4: Comparisons of means of microleakage

with different restorative materials used in study
Groups
t value p value
Significance
I : II
I : III
I : IV
I:V
I : VI
II : III
II : IV
II : V
II : VI
III : IV
III : V
III : VI
IV : V
IV : VI
V : VI

15.95
2.375
1.018
0.3393
7.126
18.32
14.93
16.29
8.822
3.393
2.036
9.501
1.357
6.108
7.465

p
p
p
p
p
p
p
p
p
p
p
p
p
p
p

<
>
>
>
<
<
<
<
<
>
>
<
>
<
<

0.001
0.05
0.05
0.05
0.001
0.001
0.001
0.001
0.001
0.05
0.05
0.001
0.05
0.001
0.001

Significant
Not significant
Not significant
Not significant
Significant
Significant
Significant
Significant
Significant
Not significant
Not significant
Significant
Not significant
Significant
Significant

glass ionomer - Ketac Molar Easy Mix was found

to be maximum (Fig. 1). So, the sealing ability in
terms of microleakage was minimum for Self-cured
GIC (Ketac Molar Easy Mix). The Compomer
(Dyract) was showing lesser sealing property
(Fig. 2) than the Packable composite (Filtek P60).
It was also observed that the microleakage along
the cavity walls was found to be more for Resin
modified Glass ionomer cement (GC Fuji II LC)
than Microfilled composite; Durafill VS (Fig. 3)

Fig. 2. Sample showing microleakage extending

into enamel at the palatal wall with no microleakage at the buccal wall

Fig. 3. Sample showing microleakage extending

into enamel and dentin at both buccal and palatal
walls

32

KANIKA VERMA GUPTA, PRADHUMAN VERMA AND ASHWARYA TRIVEDI

Fig. 4. Sample showing no microleakage

DISCUSSION
Restorative dentistry has seen a paradigm shift
from the age old principle of Extension for Prevention as laid down by Sir G.V.Black to the recent principle of restriction with conviction.
After retrieving from distilled water with few thymol crystals, to maintain aseptic conditions before cavity preparation as cited by Mali et al.
(2006), Class I cavities were prepared in each
tooth. Class I cavities were selected because of
its configuration or C factor, which corresponds
to the ratio between the number of bonded and
unbounded surfaces as suggested by Roberson
et al. (2002), Santini et al. (2004). This study used
thermo-cycling to mimic intra-oral temperature
variations and subjecting the restorations on the
tooth to temperature extremes compatible with
oral cavity.
The silver ion is extremely small 0.059 nm when
compared to a typical bacterium which is 0.5-1.0
m or internal diameter of dentinal tubules (1-4
m), therefore, silver staining technique has been
effectively used to study the degree of microleakage with a more superior definition and accurate evaluation of microleakage, as done by
Mathew et al. (2001).
The 5th generation bonding agent, Prime and
Bond NT was used as adhesive in this study,
since it has the feature of reduced number of
system components (1-bottle bonds) and is an
acetone-based adhesive system which is more
technique sensitive, suggested by Sano et al.
(1998) and Arisu et al. (2009). Incorporated hy-

drophilic components are able to dislodge moisture from the conditioned dentin and attain an
intimate interaction at the demineralized intertubular and peritubular dentin, creating the hybrid
layer, which is essential for an ideal bond to dentin, as observed by Maleknejad et al. (2009).
Santini et al. (2004), Kallenos et al. (2005) found
that 5th generation bonding agents showed minimum microleakage as compared to 6th and 7th
generation adhesive systems, so 5th generation
adhesive was preferred to evaluate the microleakage of restorative materials in our study.
The sections were then examined using 0-3
calibration, which is a parametric scale giving a
qualitative measurement of sealing effectiveness.
The mean microleakage for Filtek Z350 was least
that proves nanocomposites both stronger and
more effective at preventing secondary decay. It
provides a steady release of calcium and phosphate ions that are essential to the long-term
success, as studied by Korkmaz et al. (2010).
Durafill VS, microfilled composite showed
moderate microleakage because of the particle
size which improves the flow of material due to
improved viscosity and hence better adaptability. Also, water sorption of these materials compensates for polymerization shrinkage, which is
attributed to less filler content, according to study
conducted by Mccoy et al. (1998) and Hegde et
al. (2009).
GC Fuji II LC, resin-modified glass ionomer
cements showed higher adhesiveness to dentin
than conventional glass ionomer cements, studied by Nakanuma et al. (1998) exhibiting moderate amount of marginal leakage.
Filtek P60, packable composite contain higher
filler load as well as filler distribution, study conducted by Loguercio et al. (2004). They exhibited
more microleakage than resin modified glass
ionomers, microfilled and nanocomposites, but
less than self-cured glass ionomers and compomers.
Dyract, compomer have minimal glass ionomer reactions, it is closer to a resin composite,
thus exhibiting contraction stresses during polymerization that resulted in marginal gaps, exhibiting more marginal leakage.
Microscopically, the texture of Ketac Molar
EM appeared as granulated with many cracks
and air voids. The cohesive strength is found to
be lower than adhesive strength. Thus, the porous nature of the material is an important factor
that enhances potential of microleakage, in ac-

EVALUATION OF MICROLEAKAGE OF VARIOUS RESTORATIVE MATERIALS

cordance with the study conducted by Cho et al.

(1995) and Yaman et al. (2010).
CONCLUSION
All the restorative materials used in the study
were unable to prevent the microleakage completely. Out of all the restorative materials, Filtek
Z350 the nanocomposite displayed minimum
microleakage while the microleakage of Self-cured
glass ionomer - Ketac Molar Easy Mix was found
to be maximum. Concluding from the study, the
sealing ability in terms of microleakage can be
summarized as:
Self-cured GIC (Ketac Molar Easy Mix) <
Compomer (Dyract) < Packable composite
(Filtek P60) < Resin modified Glass ionomer
cement (GC Fuji II LC) < Microfilled composite (Durafill VS) < Nanocomposite (Filtek
Z350).
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