The aim of the study isto evaluate the effect of
primer and two different curing times of primer on
shear bond strength of orthodontic brackets bonded to
tooth surface
Materials and methods : 33 extracted first Premolar
teeth was embedded in auto-polymerizing acrylic resin
till cervical region. They were randomly divided into
three groups (each of 11 premolar). All teeth were etched
in same manner using 37% orthophosphoric acid
Etchant gel and after thatit was divided into 3 groups
Group 1: Primer was not applied, Transbond XT
Adhesive Light Cure Paste was applied and the bracket
was light cured for 20 second with standard intensity
curing light.Group 2:Transbond XT Primer was applied
and cured with high intensity LED Light(2500mW/cm2 )
for 1 second.Transbond XT Adhesive Light Cure Paste
was applied and the bracket was light cured for 20
second with standard intensity curing lightGroup 3: .
Transbond XT Primer was applied and cured with
normal intensity LED Light(1200mW/cm2 ) for 10
seconds.Transbond XT Adhesive Light Cure Paste was
applied and the bracket was light cured for 20 second
with standard intensity curing light.After bonding,each
specimen was loaded into a Universal Testing Machine
for testing. A computer connected with Universal Testing
Machine recorded the results of each test. The readings
were recorded in Newton(N). And it was converted into
Mega Pascal Units for statistical analysis.
Results : In the present study the mean SBS of no primer
group was 12.20MPa, SBS when primer was cured for 1
sec with high intensity curing light was 15.54 MPa and
SBS when primer was cured for 10 sec with normal
intensity curing light was 16.60MPa, all the three value
were more than the clinically acceptable values
Conclusion: The result of our study showed that use of
primer by curing for 1sec with high intensity LED light,
curing for 10sec with normal intensity LED light and not
using primer all three-condition produced SBS which
was clinically acceptable, but by using primer and curing
it for 1sec with high intensity LED light we can eliminate
the disadvantages which are caused by not using primer
and we can save our chair side time also by reducing the
curing time. Further studies can be done considering the
above aspects. Further research by doing a scanning
electron microscopy (SEM) study of the debonded tooth
surface to check for the enamel cracks and resin tag
formation in the various groups can be conducted to
evaluate the results better.
