title: The effect of etching time with Gluma 2000 conditioning solution on shear bond strength of a composite resin and on micromorphology of the enamel.
abstract: The purpose of this study was to assess the effect of etching time with Gluma 2000 conditioning agent on, first, the shear bond strength of composite resin to tooth enamel and, secondly, the micromorphology of the enamel. In the first part of the study flat enamel surfaces were prepared with 600-grit silicon carbide paper on 40 primary and 40 permanent teeth. Ten specimens of each group were etched for 15, 30, 60 or 120 seconds before applying bonding resin and restorative composite resin. After 24 hours' storage in water, the shear bond strength of each specimen was tested. Analysis of variance indicated a significant difference between the eight groups. However, the Student-Newman-Keuls test indicated that the only differences that were significant were the greater bond strengths of the 15-second primary tooth specimens compared with the 15- and 30-second permanent tooth specimens. In most cases the debonded specimens showed cohesive failure in resin close to the coupling interface. In the second part of the study the morphology of the enamel etching patterns in 96 other teeth was studied by scanning electron microscopy. The patterns were similar in primary and permanent teeth, and the longer the etching time the more pronounced was the pattern. The patterns produced in ground enamel were more uniform and predictable than those in pumiced enamel. Examination of bonded resin surfaces after dissolution of the teeth showed complete reproduction of the etched enamel surfaces, indicating excellent flow of the resin into the etched enamel.
authors.affiliation: Department of Conservative Dentistry, University of Bologna, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Malferrari
authors.forename: W J
authors.initials: WJ
authors.lastname: Finger
authors.forename: F
authors.initials: F
authors.lastname: Garcia-Godoy
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000704:Analysis of Variance; D003188:Composite Resins; D003737:Dental Cavity Preparation / Q000379:methods; D003738:Dental Cements; D003743:Dental Enamel / Q000648:ultrastructure*; D005998:Glycine; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010070:Oxalates; D013718:Tensile Strength; D013997:Time Factors
chemical_list: D003188:Composite Resins; D003738:Dental Cements; C092418:Gluma 2000; D010070:Oxalates; C084019:Pekafill; D005998:Glycine