surface treatment is one of the most important factors that affect the bond strength of composite resin restorations. Lasers have been studied as surface pretreatment agents with limited applications in primary teeth. Primary enamel pre-conditioning using Er, Cr:YSGG yielded controversial results as regards to enhancing enamel bond strength of composite resins to primary enamel.
Aim: The aim of the study is to evaluate and compare the shear bond strength of composite resin bonded to enamel which is pretreated using conventional phosphoric acid etchant and Er,Cr:YSGG laser.
Materials and Methods: Thirty extracted human primary molar teeth were divided into three groups, (N=10) in each (Groups I,II and III). Group I, prepared surface of enamel was etched using 37% phosphoric acid (Scotchbond, 3M). Group II, enamel was surface treated by an Er, Cr: YSGG laser system (Waterlase MD, Biolase Technology Inc., San Clemente, CA, USA) and Group III, a combination of etching and laser treatment was performed. The bonding agent (Scotchbond Multipurpose, 3M) was then applied over the test areas and light cured. Composite resin (Filtek ™ Z250 XT Nano-hybrid Universal restorative, 3M Espe) was later applied and light cured. The samples were finally tested for the shear bond strength.
Results: The Mean shear bond strength for Group III was the highest (23.2 ± 0.44MPa) Followed by Group I (17.4 ± 0.66MPa), these values were significantly higher (P < 0.01) than that of Group II (10.1 ± 0.71MPa).
Conclusion: ER,Cr.YSGG laser pretreatment of primary enamel cannot replace the acid etching.