title: Influence of glass particle size of resin cements on bonding to glass ceramic: SEM and bond strength evaluation.
abstract: This study investigated the effect of the filler particle size (micron or submicron) of experimental resin cements on the microtensile bond strength to a glass-ceramic pretreated with hydrofluoric acid (HFA) etching or alumina airborne-particle abrasion (AA). Cements were obtained from a Bis-GMA/TEGDMA mixture filled with 60 mass% micron-sized (1 ± 0.2 µm) or submicron-sized (180 ± 30 µm) Ba-Si-Al glass particles. Ceramic blocks (PM9; VITA) were treated with 10% HFA for 60 s or AA for 15 s. Silane and adhesive were applied. Ceramic blocks were bonded to resin composite blocks (Z250; 3M ESPE) using one of the cements. Bonded specimens were sectioned into beams (n = 20/group) and subjected to microtensile bond strength tests. Data were analyzed using ANOVA and Student-Newman-Keuls' tests (5%). Failure modes were classified under magnification. Morphologies of the treated ceramic surfaces and bonded interfaces were evaluated by scanning electron microscopy. The HFA-submicron group had lower bond strengths than the other groups. All AA-submicron specimens debonded prematurely. Mixed failures were predominant for HFA groups, whereas interfacial failures predominated for AA groups. SEM revealed a honeycomb-like aspect in the HFA-treated ceramic, whereas the AA-treated groups showed an irregular retentive pattern. Continuity of cement infiltration along the bonded interface was more uniform for HFA-treated compared to AA-treated specimens. Cracks toward the bulk of the ceramic were observed in AA-treated specimens. Particle size significantly influenced the ceramic bond strength, whereas surface treatment had a minor effect.
authors.affiliation: Graduate Program in Dentistry, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Valentini
authors.forename: Rafael R
authors.initials: RR
authors.lastname: Moraes
authors.forename: Tatiana
authors.initials: T
authors.lastname: Pereira-Cenci
authors.forename: Noéli
authors.initials: N
authors.lastname: Boscato
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods; D003764:Dental Materials / Q000737:chemistry* / Q000627:therapeutic use; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D019279:Resin Cements / Q000737:chemistry* / Q000627:therapeutic use; D013718:Tensile Strength
chemical_list: D003764:Dental Materials; D019279:Resin Cements; C023506:Glass ceramics
keywords: bonding; dental cements; filler particles; silicate ceramics; surface treatments