Abstract
Aims: This in vitro study was undertaken to evaluate and
compare the effect of acid etching and/or diode laser (1064
nm) irradiation on shear bond strength of orthodontic
brackets. Materials and Methods: Thirty freshly extracted
human premolars were included in this study. Laser
irradiation was done by using the new 1064 nm diode laser
with output power of 2.5 Watt in continues mode, also use
stainless steel orthodontic brackets (Roth, 22–slot size), and
use orthodontic flowable composite resin which needs no
bonding fluid. The 30 human teeth were divided into 3 groups
(each group consist of 10 teeth): Group A–use acid etching
(37% phosphoric acid) for 1 minute to bond bracket to tooth
surface (control group), group B–use laser irradiation for 30
seconds with Indian ink (coated on teeth). Group C–use laser
irradiation for 30 seconds with Indian ink after that use acid
etching for 1 minute. Shear bond strength measured by using
unconfined shear testing machine at a cross head speed of 5
mm/min. Results: The shear bond strength means were as
follows: Group A: 11.27 MPa, group B: 6.21 MPa, group C:
14.04 MPa. The acid etching after 1064 nm diode laser
irradiation (group C) has significantly higher bond strength (p
_x0001_ 0.05) than remaining groups. In group B, orthodontic
brackets had significantly lower shear bond strength (p _x0001_ 0.05)
than remaining groups. Conclusions: These results indicate
that acid etching after laser irradiation enhances and improves
the bonding of orthodontic composite resin to human enamel.
In the same time 1064 nm diode laser irradiation with ink
coating is not consider as a replacement to acid etching in
bonding of orthodontic brackets to human enamel._x0001_
