Microtensile bond strength of new self-adhesive luting agents and conventional multistep systems
Statement of problem
Several self-adhesive luting agents have recently been introduced on the market. It is crucial to know the effectiveness of such luting agents prior to their clinical application.
Purpose
The purpose of this study was to evaluate the microtensile bond strengths (μTBS) produced by different self-adhesive cements and compare them with conventional luting agents.
Material and methods
Six self-adhesive cements (RelyX Unicem (UN), RelyX U100 (UC), SmartCem 2 (SC), G-Cem (GC), Maxcem (MC), and SeT (SET), and 2 conventional luting agents, one that uses a 2-step etch-and-rinse adhesive (RelyX ARC (RX)), and one that uses a 1-step self-etching adhesive (Panavia F (PF)), were used in this study. An additional group included the use of a 2-step self-etching primer adhesive system (Clearfil SE Bond) prior to the application of Panavia F (PS). Fifty-four human molars were abraded to expose occlusal surfaces and were assigned to 9 groups according to the luting material (n=6). Five composite resin (Filtek Z250) discs (12 mm in diameter, 5 mm thick) were cemented on the teeth according to manufacturers' instructions. After 24 hours of water storage, restored teeth were serially sectioned into beams with a cross-sectional area of approximately 1 mm2 at the bonded interface and were tested in tension with a crosshead speed of 1 mm/min. Failure mode was determined using scanning electron microscopy. Data were statistically analyzed by 1-way ANOVA and Tukey's studentized range HSD test (α =.05).
Results
Mean bond strengths (SD) in MPa were: RX, 69.6 (16.6)A; PS, 49.2 (9.7)A; PF, 33.7 (13.9)AB; GC, 16.9 (10.3)BC; UC, 15.3 (3.4)BC; UN, 12.5 (2.4)C; MC 11.5 (6.8)CD; SC, 8.5 (4.9)CD; SET, 4.6 (0.5)D. Groups with different uppercase letters were significantly different from each other (P<.05). The predominant failure mode of the self-adhesive cements was adhesive between the resin cement and dentin.
Conclusions
The bond strengths produced by the multistep luting agents were significantly higher than those observed for most self-adhesive cements. (J Prosthet Dent 2009;102:306-312)
aMaster student, Department of Operative Dentistry, School of Dentistry, University of Guarulhos, Guarulhos, São Paulo, Brazil; Adjunct Faculty, Blumenau Regional University, Blumenau, Santa Catarina, Brazil
bMaster student, Department of Operative Dentistry, School of Dentistry, University of Guarulhos, Guarulhos, São Paulo, Brazil
cMaster student, Department of Operative Dentistry, School of Dentistry, University of Guarulhos, Guarulhos, São Paulo, Brazil
dPhD student, Department of Operative Dentistry, School of Dentistry, University of Guarulhos, Guarulhos, São Paulo, Brazil
eAssistant Professor, Department of Operative Dentistry, School of Dentistry, University of Guarulhos, Guarulhos, São Paulo, Brazil
fAssistant Professor, Department of Operative Dentistry, School of Dentistry, University of Guarulhos, Guarulhos, São Paulo, Brazil
Corresponding author: Dr Andre F. Reis, Department of Operative Dentistry, Guarulhos University, Rua Dr. Nilo Peçanha 81, Predio U, 6°. Andar, Guarulhos, Sao Paulo, BRAZIL, 07011-040, Fax: +55 11 2464-1758
Supported by FAPESP (The State of São Paulo Research Foundation), grants #2007/06083-4 and #2007/06447-6.
ABSTRACT