Fiber post cementation strategies: effect of mechanical cycling on push-out bond strength and cement polymerization stress.
OBJECTIVE
To evaluate the effect of mechanical cycling and cementation strategies on the push-out bond strength between fiber posts and root dentin and the polymerization stresses produced using three resin cements.


METHODS
Eighty bovine mandibular teeth were sectioned to a length of 16 mm, prepared to 12 mm, and embedded in self-curing acrylic resin. The specimens were then distributed into 8 groups (n = 10): Gr1 - Scotchbond Multi Purpose + RelyX ARC; Gr2 - Scotchbond Multi Purpose + RelyX ARC + mechanical cycling; Gr3 - AdheSE + Multilink Automix; Gr4 - AdheSE + Multilink Automix + mechanical cycling; Gr5 - phosphoric acid + RelyX U100 (self-adhesive cement); Gr6 - phosphoric acid+ RelyX U100 + mechanical cycling; Gr7 - RelyX U100; Gr8 - RelyX U100 + mechanical cycling. The values obtained from the push-out bond strength test were submitted to two-way ANOVA and Tukey's test (p = 0.05), while the values obtained from the polymerization stress test were subjected to one-way ANOVA and Tukey's test (α = 0.05).


RESULTS
Mechanical cycling did not affect the bond strength values (p = 0.236), while cementation strategies affected the push-out bond strength (p < 0.001). Luting with RelyX U100 and Scotch Bond Multi Purpose + RelyX ARC yielded higher push-out bond strength values. The polymerization stress results were affected by the factor "cement" (p = 0.0104): the self-adhesive cement RelyX U100 exhibited the lowest values, RelyX ARC resulted in the highest values, while Multilink Automix presented values statistically similar to the other two cements.


CONCLUSIONS
The self-adhesive cement appears to be a good alternative for luting fiber posts due to the high push-out bond strengths and lower polymerization stress values.
Sao Paulo State University, Sao Jose dos Campos, Brazil.
Cesar Dalmolin
CD
Bergoli
Marina
M
Amaral
Leticia Cristina
LC
Boaro
Roberto Ruggiero
RR
Braga
Luiz Felipe
LF
Valandro
D000134:Acid Etching, Dental / Q000379:methods; D000180:Acrylic Resins / Q000737:chemistry; D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002417:Cattle; D002484:Cementation / Q000379:methods*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry; D003786:Dental Pulp Cavity / Q000648:ultrastructure; D003804:Dentin / Q000648:ultrastructure; D004853:Epoxy Resins / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry; D011176:Post and Core Technique / Q000295:instrumentation*; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry*; D018915:Root Canal Preparation / Q000379:methods; D012821:Silanes / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties
D000180:Acrylic Resins; C489662:AdheSE cement; D003188:Composite Resins; D003764:Dental Materials; D004853:Epoxy Resins; D010756:Phosphoric Acids; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; D012821:Silanes; C009753:fiberglass; C502351:multilink adhesive system; C115612:single bond; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C030242:phosphoric acid