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An Evaluation of the Bond Strength using Two Different Primers (Moisture Insensitive10.5005/jp-journals-10021-1268
Primer and New Liquid Polish Sealer)
original article
An Evaluation of the Bond Strength using Two
Different Primers (Moisture Insensitive Primer and
New Liquid Polish Sealer) in Presence of
Blood and Saliva Contamination: An in vitro Study
1
Madhu Sudhan, 2SM Laxmikanth, 3Pradeep Chandra Shetty, 4CS Ramachandra, 5Sham Bhat
ABSTRACT
The practice of orthodontics often requires the bonding of
brackets under difficult conditions of moisture and blood conta­
mination. The purpose of this study were: (1) to evaluate and
compare the shear bond strength of transbond MIP and liquid
polish Biscover in dry, moist and blood contaminated conditions,
(2) to study the debonding characteristic and site of bond failure
of specimens bonded with the above primers.
Materials and methods: One hundred and sixty five human
premolars teeth were randomly divided into 11 groups of 15
samples in each group. Various enamel conditions were studied:
Dry, Saliva contaminated and blood contaminated. A light cure
bonding system (Transbond XT) was used in all the groups.
The teeth in the groups 1 to 3 were bonded with Transbond
XT primer, BisCover and MIP respectively. For groups 4 to 7a
layer of saliva and blood respectively, was applied to the etched
enamel followed by BisCover and MIP. For groups 8 to 11, a
layer of saliva and blood respectively was applied after the
application of BisCover and MIP.
Results: The shear bond strength values for groups 1 to 3 had
no statistically significant differences. When the results were
statistically evaluated, SBS of the groups contaminated before
BisCover and MIP application showed significantly smaller shear
bond values. On the other hand, teeth contaminated after Bis
Cover and MIP application had values similar to those of groups
2 and 3. There was also a statistically significant difference in
ARI scores between the dry and contaminated groups.
Conclusion: MIP and Biscover exhibited acceptable mean SBS
values in dry, moisture and blood contaminated conditions and
hence suitable for bonding the areas where there is high risk
of blood contamination.
Keywords: Shear bond strength, Moisture insensitive primer,
Biscover.
How to cite this article: Sudhan M, Laxmikanth SM,
Shetty PC, Ramachandra CS, Bhat S. An Evaluation of the
Bond Strength using Two Different Primers (Moisture Insensitive
1
Reader, 2,3,5Professor, 4Principal and Head
1
Department of Orthodontics, Farooqia Dental College
Mysore, Karnataka, India
2-5
Department of Orthodontics, AECS Maaruti Dental College
Bengaluru, Karnataka, India
Corresponding Author: Madhu Sudhan, Reader, Department
of Orthodontics, Farooqia Dental College, Mysore, Karnataka
India, Phone: 9900662482, e-mail: [email protected]
Primer and New Liquid Polish Sealer) in Presence of Blood
and Saliva Contamination: An in vitro Study. J Ind Orthod Soc
2014;48(4):319-324.
Source of support: Nil
Conflict of interest: None
Received on: 17/9/13
Accepted after Revision: 4/10/13
INTRODUCTION
Genesis of acid etching technique and subsequent adaptation
of direct bonding in orthodontics has revolutionized the
orthodontic treatment procedures.1-3 The development of
acid etch technique by Buonocore in 1955 led to direct
bonding of orthodontic brackets with composite resin,
which resulted in improvement in orthodontic treatment.4,5
Composite resin at present is the most effective and reliable
adhesive available for bonding orthodontic attachments.6,7
However, bonding orthodontic attachments to etched enamel
with resin based material is technique sensitive.5 One
disadvantage of direct bonding has been moisture control. A
variety of clinical conditions does not permit ideal isolation
for commonly used orthodontic bonding adhesive. A dry
field is paramount for successful bonding. Contamination
can occur at two critical times: after the tooth surface has
been etched and after the primer has been applied. Bonding
could be compromised at both these times. 4 Moisture
contamination with gingival fluid, saliva or blood tends to
reduce the bond strength significantly and is the major cause
for bond failure.8
Effect of moisture contamination on shear bond strength
of composite to enamel was shown by Hormetti et al and
Silverstone et al.10,11 Despite their hydroxyl groups, conven­
tional Bisphenol A glycidyl methacrylate (BIS- GMA) resins
are hydrophobic and are efficient only in a dry environ­
ment.3,5 To address this reality, some manufacturers have
introduced hydrophilic bonding materials and suggested that
it may allow successful orthodontic bonding to a moisture
contaminated enamel surface. Thus, a possible solution to
this problem has been offered by the development of new
The Journal of Indian Orthodontic Society, October-December 2014;48(4):319-324
319
Madhu Sudhan et al
hydrophilic primers (Moisture Insensitive Primer—MIP),
which have been formulated with alcohol and/or acetone
as ingredients to displace moisture from the enamel surface
isolated for bonding.5,9
A new material, liquid polish BisCover (Bisco Inc,
Schaumburg, Ill), developed to totally eliminate the formation
of the oxygen-inhibition layer by chemical means, was used
to develop a highly reactive, multifunctional, acrylate-based
light-cured surface sealant and glaze.12-19 A recent study
showed that the liquid polish BisCover can be used in direct
bonding and there was no significant change in bond strength
both in dry and contaminated conditions.20 Although literature
exists in which the bond strength of MIP and biscover have
been independently compared with conventional primers, no
reported study has compared the bond strength of all three
under different contaminated conditions.
Therefore, this study was undertaken to evaluate and
compare the shear bond strength of MIP, Biscover and con­
ven­tional (Transbond XT) primer under both dry and conta­
minated (saliva and blood) condition.
Materials and methods
A total of 165 human premolars teeth extracted for ortho­
dontic treatment were collected, cleaned of soft tissue, and
stored in a solution of 70% ethyl alcohol. The selection
criteria included teeth with good morphology, intact buccal
enamel surface, devoid of any developmental defects, caries
free, no cracks due to forceps during extraction.
The samples were divided into eleven groups comprising
of 15 samples in each group (fig. 1). One hundred and
sixty-five stainless steel metal orthodontic brackets with
0.018" slots (Maxillary PreMolar - MBT Brackets, 3M
Company) without hooks were used in the study. Light cure
orthodontic bonding resin (Transbond XT-3M Company)
were used to bond the metal brackets on the tooth surfaces.
The primer tested in this study were Transbond Moisture
Insensitive Primer (MIP-3M Unitek Monrovia, california)
and liquid polish BisCover (Bisco Inc, Schaumburg, III,
USA). A commercially available artificial saliva was used
Fig. 1: Sample size
320
which contains sodium carboxy methyl cellulose (1.0%
w/v), sorbitol (3.0% w/v), potassium chloride (0.12% w/v)
and sodium chloride (0.12% w/v) (Aqwet, CIPLA, Satara,
India). Two milliliter of freshly drawn human blood stored
with 2% EDTA was used (fig. 2). The curing light used to
initiate polymerization from the source was 3M halogen
light curing unit 2500 (3M, USA). An aluminum-mounting
jig was fabricated with the dimensions 120 mm (L) ×
47 mm (B) and 4 mm thickness, which was used to place
the samples and hold it during the test (fig. 3). The samples
were stored in deionized water at 37°C for 48 hours after
bonding (fig. 4). An Instron Universal Testing Machine
(3M model number 5500R, UK) was used to assess the
shear bond strength of the brackets (fig. 5). The scanning
electron microscope (SEM) was used to study the surface
characteristics of teeth after debonding (fig. 6).
Before bonding, the buccal surface of each tooth was
cleaned with pumice and water slurry with a dental rotary
hand piece and brush for 5 seconds, then thoroughly rinsed
with a stream of water for 10 seconds and then dried with
oil free compressed air. The dried surfaces were etched with
37% phosphoric acid gel for 30 seconds. Specimens were
then rinsed with water for 20 seconds and dried with oil free
compressed air for 10 seconds. After etching and drying the
Fig. 2: Materials used
Fig. 3: Aluminum jig
JIOS
An Evaluation of the Bond Strength using Two Different Primers (Moisture Insensitive Primer and New Liquid Polish Sealer)
Fig. 4: Deionized water
Fig. 5: Instron machine
Fig. 6: Scanning electron microscope
enamel surface of all the teeth were bonded with Transbond
XT adhesive resin using two different primers (moisture
insensitive primer and liquid polish biscover) under dry,
saliva and blood contaminated conditions.
The teeth in the groups 1 to 3 were bonded with Trans­
bond XT Primer, BisCover (Bisco Inc, Schaumburg, III,
USA) and Moisture Insensitive Primer (MIP, Transbond, 3M
Unitek) respectively. For groups 4 and 5, a layer of saliva
and blood, respectively was applied to the etched enamel
followed by BisCover. For groups 6 and 7, a layer of saliva
and blood, respectively was applied to the etched enamel
followed by MIP. The study also evaluated the contamination
after primers application in the following groups 8 to 11.
For groups 8 and 9, a layer of saliva and blood respectively
was applied after the application of Biscover. For groups 10
and 11, a layer of saliva and blood respectively was applied
after the application of Biscover (Table 1).
All the samples were stored in deionized water and
placed in an incubator at 37°C for 48 hours after bonding
to ensure complete polymerization of the adhesive material.
Then a specially prepared cylindrical plastic ring was placed
around each tooth. The ring was filled with self-curing,
fast setting acrylic until it was 3 mm below the bracket. A
Universal Testing Machine (Instron-1011) with a load cell
carrying 500 Newton’s was attached to the machine. For
measuring the shear bond strength, the prepared plastic ring
was fixed to the Aluminum Jig which in turn was positioned
in the lower cross head, with the long axis of the tooth and
the bracket base parallel to the direction of load applied
Table 1: Bonding procedure
Group 1
38% phosphoric acid
Rinsing/drying
Dry
Primer—Transbond XT light cure Adhesive transbond XT light cure
Group 2
38% phosphoric acid
Rinsing/drying
Dry
Primer—Biscover light cure
Adhesive transbond XT light cure
Group 3
38% phosphoric acid
Rinsing/drying
Dry
Primer—MIP light cure
Adhesive transbond XT light cure
Group 4
38% phosphoric acid
Rinsing/drying
Dry
Saliva and Biscover light cure
Adhesive transbond XT light cure
Group 5
38% phosphoric acid
Rinsing/drying
Dry
Blood and Biscover light cure
Adhesive transbond XT light cure
Group 6
38% phosphoric acid
Rinsing/drying
Dry
Saliva and MIP light cure
Adhesive transbond XT light cure
Group 7
38% phosphoric acid
Rinsing/drying
Dry
Blood and MIP light cure
Adhesive transbond XT light cure
Group 8
38% phosphoric acid
Rinsing/drying
Dry
BisCover light cure and saliva
Adhesive transbond XT light cure
Group 9
38% phosphoric acid
Rinsing/drying
Dry
BisCover light cure and blood
Adhesive transbond XT light cure
Group10
38% phosphoric acid
Rinsing/drying
Dry
MIP light cure and saliva
Adhesive transbond XT light cure
Group 11
38% phosphoric acid
Rinsing/drying
Dry
MIP light cure and blood
Adhesive transbond XT light cure
The Journal of Indian Orthodontic Society, October-December 2014;48(4):319-324
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Madhu Sudhan et al
Fig. 7: Sample under testing procedure
(fig. 7). A wire loop was made using 23 gauge stainless steel
wire and the ends of the wire were gripped in the upper jaw
(cross head) and under the gingival tie wings by adjusting
the cross head. The cross head moved at a uniform speed of
3 mm/min. The load was progressively applied till the
bracket got detached from the tooth surface and the reading
was recorded in newtons for every specimen and then
converted into Megapascals (Mpa).
After debonding of the brackets, the surface of the teeth
were examined to assess the adhesive remnant index (ARI),
which describes the amount of composite adhesive that
remains on the surface of the tooth. Eleven specimens in each
group were selected, which had given highest bond strength.
All specimens were mounted on carbon stubs and
prepared for SEM study by Sputtering with gold palladium
in a high vacuum evaporator (JFC 1100E ion sputtering
device JEOL Ltd, Tokyo, Japan for 6 minutes (Fig. 8).
They were examined in JSM-840 SEM (JEOL Ltd, Tokyo,
Japan) operated at 10 KV. Photographs were taken at the
magnification of 50, 100, 500 and 1000× to analyze the site
of bond failure.
Statistical Analysis
Descriptive statistics including mean, standard deviation
and coefficient of variation values were calculated for each
of the 3 groups. Difference between the groups were then
evaluated by a one-way analysis of variance (ANOVA)
(Table 2). This was followed by pair wise comparison of the
material groups using Tukey’s significant differences (TSD)
test to find out how the procedural groups differed from
each other. The Chi-square test was used to determine the
statistical differences in the ARI scores among the different
groups (Table 3).
322
Fig. 8: Samples after gold sputtering
Results
This study evaluated the bond strength using two different
primers (moisture insensitive primer and new liquid polish
sealer) in presence of blood and saliva contamination and
also the surface characteristic of the debonded tooth surface
using the SEM. The shear bond strength values for groups 1
and 2 (Biscover group) and group 3 (MIP group) had no
statistically significant differences. When the results were
statistically evaluated, shear bond strengths of the groups
contaminated before Biscover and MIP application showed
significantly smaller shear bond values. On the other hand,
teeth contaminated after BisCover and MIP application had
values similar to those of groups 2 and 3. In the groups
contaminated before Biscover and MIP application, the
blood contaminated groups 4 and 6 had lower values than the
saliva contaminated groups 5 and 7. The blood contaminated
groups 8 and 10, contaminated after Biscover and MIP
application, did not differ significantly (Graph 1). There
was also a statistically significant difference in ARI scores
between the dry and contaminated groups.
The ARI scores recorded in each group were compared
using chi-square test. Score 4 is found to be more in Groups
1, 9 and 11. Score 0 and 1 is found to be more in Groups 2,
4, 5, 6, 7 and 8. Contaminated groups showed less adhesive
remaining due to bond failure at tooth and adhesive interface
whereas dry groups showed bond failure at adhesive and
bracket interface which revealed through SEM (Table 2).
Discussion
The effect of two contaminants, blood and saliva, were
evaluated before and after the application of the biscover
and MIP. The bond strength values of biscover and MIP
JIOS
An Evaluation of the Bond Strength using Two Different Primers (Moisture Insensitive Primer and New Liquid Polish Sealer)
Table 2: ANOVA test for comparison of mean shear
bond strength of samples in MPa
Groups
1
2
3
4
5
6
7
8
9
10
11
Mean
13.67
12.52
12.01
3.94
8.06
7.02
9.67
12.17
12.76
13.11
13.20
SD
4.03
4.43
5.87
1.27
2.03
3.02
2.22
1.90
2.81
1.28
2.25
Median
14.34
12.92
11.49
4.10
8.16
6.60
10.22
12.15
13.11
13.22
13.58
Min.
2.31
2.25
0.05
1.88
5.28
2.85
4.12
10.21
6.09
10.45
9.13
Max. F
p-value
17.98 15.185 < 0.001
18.64
21.01
6.86
11.97
13.99
12.62
17.90
18.96
15.60
16.45
Table 3: Analysis of ARI scores
Groups
Scores
0
1
2
1
1
4
1
2
5
5
3
3
2
4
3
4
6
7
2
5
6
5
2
6
7
6
2
7
4
7
2
8
2
7
3
9
0
0
3
10
1
5
5
We compare the ARI scores
chi-square test
χ2
p-value
3
4
4
5
2
0
5
1
0
0
2
0
0
0
1
1
76.243 <0.001
2
1
8
4
3
1
recorded in each group using
were compared individually in blood and saliva conta­
minated conditions. But, both the materials were not
compared together until now.
The first step of the experiment was to test whether
additional bonding was needed when Biscover and MIP
was used as priming agent. The results of mean shear
bond strength in the present study showed that for Group 1
(Transbond Primer—control): 13.9 MPa, Group 2 (bisCover
group): 12.8 MPa and Group 3 (MIP group): 12.2 MPa. The
descriptive statistics (Graph 1) of Biscover and MIP clearly
showed that under dry condition the bond strength values
were above 6 to 8 MPa, which was suggested by Reynolds14
as the clinically acceptable standard.
The second step involved the test of blood and saliva
contamination before Biscover and MIP application. The
results of mean shear bond strength in the present study
showed that for Group 4 (+ BisCover): 3.94 MPa, Group 5
(blood + BisCover): 8.06 MPa, Group 6 (saliva + MIP): 7.02
MPa and Group 7 (blood + MIP): 9.67 MPa. The descriptive
statistics of Biscover and MIP clearly showed that under
blood and saliva contamination the bond strength values
were significantly affected.
Hence, it is infered from the present study that conta­
mination with blood and saliva significantly reduces bond
strength. The groups contaminated with blood showed
reduced bond strength than saliva contamination. Sayinsu
K et al20 also showed that contamination with blood before
biscover application has reduced bond strength which
supports our study.
Sayinsu K et al20 also showed that contamination with
saliva before Biscover application has bond strength well
above clinically acceptable standard which supports our study.
The third step involved the test of blood and saliva
contamination after Biscover and MIP application. The
results of mean shear bond strength in the present study
showed that for Group 8 (BisCover + saliva): 12.4 MPa,
Group 9 (Biscover + blood): 13.0 MPa, Group 10 (MIP
+ saliva): 13.4 MPa, Group 11 (MIP + blood): 13.5 MPa.
Hence, it can be inferred from the present study that
contamination with blood and saliva after Biscover and MIP
application has bond strength well above clinically acceptable
standards. Bishara SE16 showed that contamination after
MIP application has bond strength width above clinically
Graph 1: Mean shear bond strength (MPa) between groups
The Journal of Indian Orthodontic Society, October-December 2014;48(4):319-324
323
Madhu Sudhan et al
acceptable standards, which support the present study.
Sayinsu K et al20 also showed that contamination after
Biscover application has bond strength well above clinically
acceptable standard which supports our study.
The fourth step involved the examination of debonding
characteristic and the site of bond failure of specimens
bonded with the above primers through SEM. From the
present study, it is inferred that contaminated groups show
less adhesive remaining due to bond failure at tooth and
adhesive interface whereas dry groups shows bond failure
at adhesive and bracket interface. On the contrary, bloodcontaminated groups had a higher frequency of bond failure
at the enamel-adhesive interface. It was later conformed
through SEM. No enamel fractures were observed in all
the three groups.
Conclusion
Biscover and MIP can be applied to tooth surface before
bracket bonding without affecting bond strength. This
study also showed that blood contamination on acid-etched
surface reduces bond strength to a greater extent than saliva
contamination. When Biscover or MIP is used a negative
effect of blood or saliva contamination on bond strength is
prevented.
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