Parameters affecting degree of conversion of dual-cure resin cements in the root canal: FTIR analysis.
OBJECTIVE
To evaluate the degree of conversion of dual-cured resin cements applied for luting of translucent and opaque fibre posts.


METHODS
Two dual-cured resin cements, RelyX ARC and Nexus 2, were used to cement 2 types of tooth-coloured fibre posts, D.T. Light-Post (translucent) and D.T. White-Post (opaque). The degree of conversion for each resin cement was measured. Post-curing polymerization and chemical curing of the cements were also measured. The degree of conversion was measured at various distances (4, 6 and 8 mm) from the tip of the light-curing unit by Fourier transform infrared spectroscopy. The data were analyzed with analysis of variance and post hoc tests (α = 0.05).


RESULTS
The degree of conversion of the dual-cure cements was significantly higher with the D.T. Light-Posts than with the D.T. White-Posts (p < 0.05). No significant difference was observed in the degree of conversion at different depths for the RelyX ARC resin cement in conjunction with the D.T. Light-Posts (p > 0.05). The overall degree of conversion decreased linearly with increasing distance from the light-curing tip. Monitoring of post-curing polymerization and chemical curing revealed no further increase in degree of conversion after 5 minutes (p > 0.05).


CONCLUSIONS
The translucent fibre posts (D.T. Light-Posts) allowed a significantly higher degree of conversion with dual-cure resin cements than the opaque fibre posts (D.T. White-Posts) because of the light-transmitting property of their optical fibres.
Iran Polymer and Petrochemical Institute, Tehran, Iran.
Niloofar
N
Shadman
Mohammad
M
Atai
Maryam
M
Ghavam
Hamid
H
Kermanshah
Shahram Farzin
SF
Ebrahimi
D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D006244:Hardness; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D011092:Polyethylene Glycols / Q000737:chemistry*; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry*; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry*; D012390:Root Canal Therapy / Q000295:instrumentation*; D055116:Self-Curing of Dental Resins; D017550:Spectroscopy, Fourier Transform Infrared
C433206:Nexus; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate