Long-term bond between dual-polymerizing cementing agents and human hard dental tissue.
OBJECTIVE
To examine the long-term adhesion of seven dual-polymerizing cementing agents to human dentin in vitro.


METHODS
Two hundred and eighty extracted non-carious human molars were ground flat to expose dentin surfaces. The bond strengths of cementing agents with their respective bonding systems were examined: one compomer cement (PermaCem), five resin cements (RelyX ARC, Panavia F, Variolink II, Nexus 2, Calibra) and one self-adhesive universal resin cement (RelyX Unicem). One subgroup (n=10) was tested after 150 days of storage in water at 37 degrees C (time t(1)), the other subgroup (n=10) was tested after 150 days of storage plus 37,500 thermal cycles (time t(2)). All specimens were stressed in shear at a constant crosshead speed of 0.5mm/min until failure. Statistical analysis was performed by ANOVA, taking effect interactions into account. The Tukey method was used for multiple paired comparisons (alpha=0.05).


RESULTS
The three-way ANOVA (cementing agents, polymerization methods, times of measurements) showed Variolink II to have the highest strength at 9.9+/-4.5MPa. Values were slightly higher at t(1) (5.9+/-4.7MPa) than at t(2) (4.9+/-4.2MPa) (p=0.0044). Polymerization with light activation (6.5+/-5.1MPa) yielded higher strengths than polymerization without (4.3+/-3.3MPa) (p<0.0001). Separate two-way ANOVAs for t(1) and t(2) showed that the two main effects (cementing agent, polymerization method) and their interactions differed significantly.


CONCLUSIONS
Cementing agents/adhesive systems and the polymerization method influence the long-term bond to hard dental tissues.
Department of Prosthodontics, School of Dentistry, Johann Wolfgang Goethe University of Frankfurt/Main, Germany. piwowarczyk@gmx.de
Andree
A
Piwowarczyk
Ralf
R
Bender
Peter
P
Ottl
Hans-Christoph
HC
Lauer
D000134:Acid Etching, Dental; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D020770:Compomers / Q000737:chemistry; D001840:Dental Bonding; D003804:Dentin / Q000648:ultrastructure*; D006801:Humans; D008027:Light; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry* / Q000528:radiation effects; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
C433205:Calibra; D020770:Compomers; C433206:Nexus; C438843:Panavia-Fluoro; D011108:Polymers; D011109:Polymethacrylic Acids; C483701:Rely X Unicem; C462240:RelyX ARC; D019279:Resin Cements; D014867:Water; C065770:Herculite XR; C103502:Variolink; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate