title: Comparison of shear bond strength of composite resin to enamel surface with laser etching versus acid etching: An in vitro evaluation.
abstract: BACKGROUND
  The aim of the study is in vitro evaluation of the shear bond strength of composite resin bonded to enamel which is pretreated using acid etchant and Er,Cr:Ysgg.
  
  
  METHODS
  40 extracted human teeth were divided in two groups of 20 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 a an Er, Cr: YSGG laser system (Waterlase MD, Biolase Technology Inc., San Clemente, CA, USA) operating at a wavelength of 2,780 nm and having a pulse duration of 140-200 microsecond with a repetition rate of 20 Hz and 40 Hz. Bonding agent ((Scotchbond Multipurpose, 3M) was applied over the test areas on 20 samples of Groups A and B each, and light cured. Composite resin (Ceram X duo Nanoceramic restorative, Densply) was applied onto the test areas as a 3 × 3 mm diameter bid, and light cured. The samples were tested for shear bond strength.
  
  
  RESULTS
  Mean shear bond strength for acid-etched enamel (26.41 ± 0.66MPa, range 25.155 to 27.150 MPa) was significantly higher (P < 0.01) than for laser-etched enamel (16.23 ± 0.71MPa, range 15.233 to 17.334 MPa).
  
  
  CONCLUSIONS
  For enamel surface, mean shear bond strength of bonded composite obtained after laser etching were significantly lower than those obtained after acid etching.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vasantdada Patil Dental College and Hospital, Kavalapur, Sangli, Maharashtra, India.
authors.forename: Upendra A
authors.initials: UA
authors.lastname: Hoshing
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vasantdada Patil Dental College and Hospital, Kavalapur, Sangli, Maharashtra, India.
authors.forename: Suvarna
authors.initials: S
authors.lastname: Patil
authors.affiliation: Department of School of Dental Sciences, Krishna Institute of Medical Sciences Deemed University, Malakapur, Karad, Maharashtra, India.
authors.forename: Ashish
authors.initials: A
authors.lastname: Medha
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vasantdada Patil Dental College and Hospital, Kavalapur, Sangli, Maharashtra, India.
authors.forename: Siddhesh Dattatray
authors.initials: SD
authors.lastname: Bandekar
keywords: Enamel etching; chromium:yttrium; erbium; gallium; garnet laser; laser etching; phosphoric acid etching; scandium; shear bong strength