Effects of light-, self-, and tack-curing on degree of conversion and physical strength of dual-cure resin cements.
OBJECTIVE
To evaluate the polymerization degree of conversion (DC) and physical strength of dual-cure cements with tack-curing, and compare them to those with light-curing and self-curing resins.


METHODS
Four dual-cure resin cements were evaluated by DC and diametral tensile strength (DTS) tests with three different polymerization methods: Light-cure (photo-polymerization 40 seconds, self-curing 30 minutes); Self-cure (self-curing 30 minutes); and Tack-cure (photo-polymerization 3 seconds, self-curing 30 minutes). Polymerization degree of conversion was determined using Fourier transform infrared spectroscopy, and calculated based on the ratio changes of aliphatic-to-aromatic C=C IR absorption peaks before and after polymerized. Specimens for DTS (n = 10) were prepared using circular molds (6.0 mm in diameter and 3.0 mm in height) and tested after 24-hour water storage. Data were analyzed by two-way ANOVA. Multiple post-hoc pairwise comparisons were performed by t-test when significant effects were found across the factors (α = 0.05). Results: The Self-cure groups had slow initial curing rate, resulting in the lower DC than both the Light-cure and Tack-cure groups. After 30 minutes of polymerization, only in the RelyX Ultimate group, light-curing resulted in higher DC than tack-curing, which resulted in higher DC than self-curing (P < 0.05). The self-cure of resin cements resulted in a significantly lower DTS only for RelyX Ultimate cement (P < 0.05). There was no significantly different DTS between the Tack-cure and Light-cure groups for all of the resin cements. For all of the three curing modes, RelyX Ultimate cements had the lowest DTS among the four cements tested in this study.
Liang
L
Chen
Byoung In
BI
Suh
Christine
C
Gleave
Won Jun
WJ
Choi
Jihye
J
Hyun
Jiyun
J
Nam
D055117:Curing Lights, Dental; D001840:Dental Bonding / Q000379:methods*; D008422:Materials Testing; D058105:Polymerization