Some of the bonding systems used in this study have achieved unchanged dentin bond strengths after thermal cycling. Therefore, by choosing appropriate adhesive systems, the simplified clinical procedures offered by single-step self-etch systems can be exploited even after thermal cycle stress. SUMMARYThis study investigated the influence of thermal cycling on the dentin bond strengths of singlestep self-etch adhesive systems. The Absolute, Clearfil Tri-S Bond, G-Bond and One-Up Bond F Plus systems were used. Bovine mandibular incisors were mounted in self-curing resin, and the facial surfaces were wet ground with #600 SiC paper. Adhesives were applied to the prepared dentin surfaces, and they were light irradiated according to each manufacturer's instructions. Resin composites were condensed into a mold (4 mm in diameter and 2 mm in height) and light irradiated for 30 seconds. Bonded specimens were divided into three groups and subjected to different storage conditions as follows: 37°C water for 24 hours; 37°C water for 24 hours followed by 10,000 thermal cycles between 5°C and 60°C or 37°C water for 24 hours followed by 20,000 thermal cycles between 5°C and 60°C. Ten samples per group were tested in a shear mode at a crosshead speed of 1.0 mm/minute. Analysis of variance and Tukey's HSD test at the 0.05 significance level were used to compare the three storage conditions for each adhesive system. After 24 hours storage in water, the mean dentin bond strengths ranged from 11.4 MPa to 17.1 MPa. The Clearfil Tri-S Bond system showed the highest bond strength. After 10,000 thermal cycles, the mean bond strengths remained unchanged Youhei Asaka, DDS, graduate student,

The purpose of this study was to evaluate the adhesive performance of luting cements to a noble metal alloy treated with metal conditioners.Cast disk specimens made of a noble metal alloy were gritblasted with alumina followed by no treatment or priming with two different types of metal conditioner.A mold was placed on the metal surface and filled with luting cement. Ten samples per test group were stored in 37°C distilled water for 24 hours, then shear tested at a cross-head speed of 1.0 mm/minute.ANOVA and Tukey's HSD tests (a = 0.05) were done. The mean bond strength of resin-modified glass ionomer cement increased significantly with metal conditioner application compared to the controls, indicating the efficacy of the tested metal conditioners in improving bond strength.Based on the results of this study, it seemed to be a useful method to incorporate a functional monomer into resin cements so as to improve the bond strength to a noble metal alloy.

After thermal cycling, some recently introduced simplified bonding systems showed no change in enamel bond strengths. The systems used were Absolute, Clearfil tri-S Bond, G-Bond and One-Up Bond F Plus. Bovine mandibular incisors were mounted in self-curing resin, and the facial surfaces were wet ground with #600 SiC paper. Adhesives were applied on the prepared enamel surfaces and light irradiated according to each manufacturer's instructions. Resin composites were condensed into a mold (ø4x2 mm) and light irradiated for 30 seconds. Thirty specimens per adhesive systems were divided into 1 of 3 test groups (n=10) following storage in water at 37°C for 24 hours. The specimens were then stored in 37°C water for 24 hours, followed by thermal cycling 10,000 and 20,000 times between 5°C and 60°C. After each storage condition, the specimens were tested in shear mode at a crosshead speed of 1.0-mm/minute. One-way ANOVAs and Tukey HSD test at a level of 0.05 were conducted.After 24 hours of water storage, the mean enamel bond strengths ranged from 11.3 to 16.9 MPa, and Clearfil tri-S Bond showed significantly higher bond strength. After thermal cycling, the mean bond strengths ranged from 8.3 to 20.7 MPa. The changes in enamel bond strengths were different among the adhesive systems tested. Failure modes after the test were commonly adhesive failure associated with partial cohesive failure adhesive in resin.