Luting glass ceramic restorations using a self-adhesive resin cement under different dentin conditions.
OBJECTIVE
The aim of this study was to investigate the bond strength of ceramic restorations luted using a self-adhesive resin cement (RelyX Unicem, 3M ESPE) under different dentin conditions.


METHODS
In the experimental groups, ceramic restorations were luted to bovine incisors with RelyX Unicem under the following conditions: [Dry dentin]: surface was dried using air stream for 15 s; [Moist dentin]: excess dentin moisture was removed with absorbent paper; [Bonding agent]: Clearfil SE Bond (Kuraray) self-etching adhesive system was previously applied to dentin. In the Control group, cementation was done using an etch-and-rinse adhesive (Excite DSC) and Variolink II resin cement (Ivoclar Vivadent). Photoactivation of the resin cements was performed with UltraLume LED 5 unit (Ultradent). The restorations (n=5 per group) were sectioned into beams and microtensile testing was carried out. Data were subjected to ANOVA and Tukey's test (p<0.05). Failure modes were classified under Scanning Electron Microscopic (SEM) (x120 magnification).


RESULTS
The bond strength was dependent on the moisture status of the dentin. Bond strength in the "dry dentin group" was significantly lower than that of all other groups, which showed similar results. A predominance of mixed failures was detected for the control group, while a predominance of adhesive failures was observed for the "bonding agent" and "dry dentin" groups. The "moist dentin" group presented predominantly cohesive failures within the luting material. The previous application of a self-etching adhesive showed no significant effect.


CONCLUSIONS
Only excess dentin moisture should be removed for the cementation of ceramic restorations with self-adhesive resin cements.
Guarda
Guilherme B
GB
Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
Gonçalves
Luciano S
LS
Correr
Américo B
AB
Moraes
Rafael R
RR
Sinhoreti
Mário A C
MA
Correr-Sobrinho
Lourenço
L
D000134:Acid Etching, Dental / Q000379:methods; D000268:Adhesiveness; D000388:Air; D000538:Aluminum Silicates / Q000737:chemistry; D000818:Animals; D002417:Cattle; D002484:Cementation / Q000379:methods; D002516:Ceramics / Q000737:chemistry*; D055117:Curing Lights, Dental / Q000145:classification; D001840:Dental Bonding / Q000379:methods*; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D003804:Dentin / Q000648:ultrastructure*; D003890:Desiccation; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry*; D013314:Stress, Mechanical; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
D000538:Aluminum Silicates; C438313:Clearfil SE Bond; D003764:Dental Materials; C420130:Excite cement; C075815:IPS-Empress ceramic; D008689:Methacrylates; C483701:Rely X Unicem; D019279:Resin Cements; D014867:Water; D003776:Dental Porcelain; C078519:leucite; C103502:Variolink; C023506:Glass ceramics