Influence of low concentration acid treatment on lithium disilicate core/veneer ceramic bond strength.
OBJECTIVE
This study evaluated the influence of low concentration acid treatment on the shear bond strength between lithium disilicate (LD) infrastructure and veneering porcelain. The surface morphology characteristic after this acid treatment was also examined.


METHODS
LD reinforced ceramic cylinders (n=10) (IPS e.max Press, Ivoclar-Vivadent, Schaan, Liechtenstein) were treated (LD-treated) with a low concentration acid solution (Invex Liquid - Ivoclar-Vivadent, Schaan, Liechtenstein) or not treated with the acid solution (LD-untreated). They were veneered with a glass ceramic (IPS e.max Ceram, Ivoclar-Vivadent, Schaan, Liechtenstein). A metal ceramic group (CoCr) was tested as control. Shear bond strength (SBS) was conducted using a universal testing machine at 0.5 mm/min. Surface morphology characteristics after acid treatment were analyzed using scanning electron microscopy.


RESULTS
The acid treatment at low concentrations did not influence the SBS of the LD/veneering porcelain interface. The CoCr group showed the significant higher SBS value (35.59 ± 5.97 MPa), followed by LD-untreated group (27.76 ± 3.59 MPa) and LD-treated (27.02 ± 4.79 MPa). The fracture modes were predominantly adhesive for CoCr group and cohesive within the infrastructure for DL groups. Scanning Electron Microscopy (SEM) analysis showed no morphological differences between treated and untreated LD surfaces.


CONCLUSIONS
Low concentration acid treatment did not improved SBS of veneering ceramic to LD and did not cause morphological changes on the LD surface. Key words:Lithium disilicate, glass ceramics, acid etching, shear bond strength, scanning electron microscopy.
Ph.D. Candidate. Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
Hugo A
HA
Vidotti
Undergraduate Student. Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
Rudan P
RP
Garcia
Professor. Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
Paulo Cr
PC
Conti
Professor, Department of Prosthodontics, School of Dentistry, University of Southern Santa Catarina.
Jefferson R
JR
Pereira
Professor. Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
Accácio Ld
AL
Valle