Evalaution Of Shear Bond Strength Of Orthodontic Brackets Bonded To Enamel Surface With Laser Conditioning. - An In Vitro Study

Abstract

AIM : The Aim of the study is an  In-vitro evaluation of the shear bond strength of composite resin bonded to enamel which is pretreated using acid etchant and Laser etching .
MATERIALS AND METHODS: 32 extracted human teeth were divided in two groups of 16 each (Groups A and B). In Group A, prepared surface of enamel was etched using 37% phosphoric acid (Scotchbond, 3M). In Group B, enamel was surface treated by laser Er: Cr: YSGG (Waterlase MD,  I plus Biolase Technology Inc., San Clemente, CA, USA) operating at a wavelength of 2,780 nm and having a pulse duration of 60ms in H mode with at 2W/30 Hz .Bonding agent (Scotchbond Multipurpose, 3M) was applied over the test areas on 16 samples of Groups A and B each, and light cured. Composite resin (Transbond XT ,3M) . The samples were tested for shear bond strength.
RESULTS:Mean shear bond strength for acid-etched enamel was (11.93 ± 1.06MPa) significantly higher (P < 0.01) than for laser-etched enamel(9.56 ± 1.25 MPa) ARI revealed both laser etched and acid etched revealed  a score 2  more than half the adhesive on tooth surface .
CONCLUSIONS:For enamel surface, mean shear bond strength of bonded composite obtained after laser etching were lower than those obtained after acid etching.ARI scores had negligible differences betweens the acid etched and laser etched.