Sealant bond strengths of CO(2) laser-etched versus acid-etched bovine enamel.
OBJECTIVE
The purpose of this study was to evaluate sealant shear bond strength on bovine enamel with standard acid etching compared with CO(2) laser etching.


METHODS
Bovine enamel was prepared either by acid or laser etching and divided into four experimental groups, either acid or laser-etched teeth with or without a primer. A gelatin capsule was used to place the sealant on the prepared enamel surface and the bond tested in shear. Also surface roughness was evaluated by using a surface analyzer and an atomic force microscope.


RESULTS
Shear bond strength results were the following: acid etch = 8.8 +/- 3.8 MPa, acid etch with primer = 10.3 +/- 5.5 MPa, laser etch = 4.0 +/- 1.1 MPa, and laser etch with primer = 6.2 +/- 2.3 MPa. Analysis of variance statistical analysis found no significant difference in bond strength between the acid-etched groups. However, the laser-etched groups had significantly lower bond strengths from the acid-etched teeth. In addition, a significant difference was observed between the laser-etched groups, where the use of the primer helped to increase the bond strength of the sealants. The surface roughness was significantly greater on the laser-etched teeth at the microm level (by using a surface analyzer) from the acid-etched and the control specimens. No difference in roughness (by using an atomic force microscope) was observed at the nanometer level between the laser and acid-etched teeth.


CONCLUSIONS
For these particular settings, the laser-etched teeth resulted in lower bond strengths to enamel and the use of a primer increased the bond strength for laser-etched teeth only.
Drummond
J L
JL
Department of Restorative Dentistry, University of Illinois at Chicago, Chicago, Illinois 60612-7212, USA. drummond@uic.edu
Wigdor
H A
HA
Walsh
J T
JT
Fadavi
S
S
Punwani
I
I
D000134:Acid Etching, Dental; D000818:Animals; D002245:Carbon Dioxide; D002417:Cattle; D001840:Dental Bonding / Q000379:methods*; D003743:Dental Enamel; D003762:Dental Instruments; D066298:In Vitro Techniques; D053685:Laser Therapy; D010895:Pit and Fissure Sealants; D013718:Tensile Strength
D010895:Pit and Fissure Sealants; D002245:Carbon Dioxide