JOURNAL OF PROSTHETIC DENTISTRY THE

Vol. 101 No. 2      February - 2009

ISSN: 0022-3913      UBIC: 171

SUMMARY

Statement of problem. Lack of knowledge regarding the kinetics of the setting reaction of dual- and autopolymerizing resin luting agents (RLA) leads the clinician to underestimate the care required during occlusal adjustments of indirect restorations. Purpose. The purpose of this study was to evaluate the degree of conversion (DC), maximum rate of polymerization (Rpmax ), and potential of cure (ratio of conversions in autopolymerized relative to dual-polymerized modes; PCA/D) of 5 dual-polymerizable RLAs at 5 and 10 minutes, after mixing RLA components using infrared (IR) spectroscopy. Material and methods. The RLAs evaluated included Calibra, Duo-Link, Lute-It, Nexus 2, and RelyX ARC. The RLAs were manipulated and applied to the horizontal diamond element in the optical bench of an IR spectrometer. The materials were either light activated for 40 seconds (dual-polymerizing mode) or were allowed to autopolymerize (autopolymerizing mode). The DC, Rpmax and PCA/D were calculated using standard techniques of observing changes in aliphatic-to-aromatic peak ratios before and after polymerization. Data (n=5) were analyzed by 2-way repeated measures ANOVA and Tukey's post hoc test (α=.05). Results. All autopolymerizing groups exhibited lower DC and Rpmax values than the dual-polymerizing groups (P<.001), and higher DC values at 10 minutes than at 5 minutes, only in tie autopolymerizing mode. Duo-Link exhibited the highest Rpmax values among dual-polymerizing groups, while Lute-It and Calibra showed the lowest Rpmax values and the highest PCA/D values. Within autopolymerizing groups, Nexus 2 and Lute-It exhibited the highest Rpmax values, while RelyX ARC demonstrated the lowest Rpmax as well as the lowest PCA/D values. Conclusions. The DC values of all autopolymerized groups of RLAs were lower than those of the dual-polymerized RLAs, but the differences in Rpmax and PCA/D were product dependent. The DC of ah products was higher at the 10-minute interval than at the 5-minute interval, only in the autopolymerizing mode. (J Prosthet Dent 2009; 101:128-136)

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