SEM observation of the bond integrity of fiber-reinforced composite posts cemented into root canals.
OBJECTIVE
To test the null hypothesis that continuity of resin cement/dentin interfaces is not affected by location along the root canal walls or water storage for 3 months when bonding fiber posts into root canals.


METHODS
Fiber posts were luted to bovine incisors using four resinous luting systems: Multilink, Variolink II, Enforce Dual and Enforce PV. After cementation, roots were longitudinally sectioned and epoxy resin replicas were prepared for SEM analysis (baseline). The original halves were immersed in solvent, replicated and evaluated. After 3 months water storage and a second solvent immersion, a new set of replicas were made and analyzed. The ratio (%) between the length (mm) of available bonding interface and the actual extension of bonded cement/dentin interface was calculated.


RESULTS
Significant lower percent values of bond integrity were found for Multilink (8.25%) and Variolink II (10.08%) when compared to Enforce Dual (25.11%) and Enforce PV (27.0%) at baseline analysis. The same trend was observed after immersion in solvent, with no significant changes. However, bond integrity was significantly reduced after 3 months water storage and a second solvent immersion to values below 5% (Multilink=3.31%, Variolink=1.87%, Enforce Dual=1.20%, and Enforce PV=0.75%). The majority of gaps were depicted at the apical and middle thirds at baseline and after immersion in solvent. After 3 months, gaps were also detected at the cervical third.


CONCLUSIONS
Bond integrity at the cement/dentin interface was surprisingly low after cementation of fiber posts to root canals with all resin cements. That was not significantly altered after immersion in solvent, but was further compromised after 3 months water storage. Gaps were mainly seen at middle and apical thirds throughout the experiment and extended to the cervical third after water storage for 3 months. Bond integrity of fiber posts luted to root canals was affected both by location and water storage.
Department of Prosthodontics, Integrated Center for Research, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil. estevamab@hotmail.com
Estevam A
EA
Bonfante
Luiz F
LF
Pegoraro
Mario F
MF
de Góes
Ricardo M
RM
Carvalho
D000818:Animals; D002417:Cattle; D003188:Composite Resins; D003362:Cost-Benefit Analysis; D001840:Dental Bonding; D017268:Dental Prosthesis Retention; D003786:Dental Pulp Cavity; D003799:Dental Stress Analysis; D003804:Dentin; D004356:Drug Storage; D008855:Microscopy, Electron, Scanning; D011176:Post and Core Technique / Q000191:economics; D019279:Resin Cements; D014867:Water
D003188:Composite Resins; C113550:FiberKor, sculpture; D019279:Resin Cements; D014867:Water