The purpose of this study was to analyze the ions released from a surface pre-reacted glass ionomer (S-PRG) filler in distilled water or lactic acid solution. S-PRG filler was mixed with either solution at 1000:1, 100:1, 10:1, and 1:1 ratios by weight. By means of inductively coupled plasma atomic emission spectroscopy and a fluoride electrode, elements released from S-PRG filler were identified to be Al, B, Na, Si, Sr, and F. To investigate the effect of solution pH on ion release, the pH values of the solutions before mixing and after 24 hours' mixing with S-PRG were measured. After 24 hours' mixing, the pH values of solutions at all ratios became more neutral or weakly alkaline regardless of their initial pH levels before mixing. In conclusion, results showed that S-PRG filler released several types of ions, and that ion release was influenced by the mixing ratio of the solution rather than the initial pH of the solution.

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SUMMARYThis study examined the relationship between the adhesive application time and enamel bond strength of several single-step self-etch adhesive systems. The adhesives used were: Bond Force (BF, Tokuyama Dental Corporation, Tokyo, Japan), Clearfil tri-S Bond (CT, Kuraray Medical Inc, Tokyo, Japan), iBond Self-Etch (IB, Heraeus Kulzer, Armonk, NY) and OptiBond All-in-One (OB, sds Kerr). Bovine mandibular incisors were mounted in self-curing resin and wet ground with #600-grit silicon carbide paper to expose labial enamel. Adhesives were applied for 10, 20 or 40 seconds and the resin composites were condensed into a mold (ø4 x 2 mm) on the enamel and light irradiated. Ten samples per test group were stored in 37°C water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/minute. One-way ANOVA and the Tukey HSD test (α α=0.05) were performed within each adhe-

The purpose of this study was to examine the microtensile bond strength of a single-step selfetch adhesive system (Clearfil tri-S Bond and One-Up Bond F Plus) to bovine dentin. Adhesive was applied to a flat dentin surface, and resin composite was bonded according to the manufacturers' instructions. After 24 h storage in distilled water at 37°C, hourglassshaped specimens were produced. These were subjected to microtensile bond strength testing at a cross-head speed of 1.0 mm/min. The results were analyzed using Student's t-test at a significance level of 0.05. Fieldemission scanning electron microscopy (FE-SEM) observations of the fractured specimens and the adhesive-treated dentin surfaces were also conducted. The bond strength of Clearfil tri-S Bond was not significantly different from that of One-Up Bond F Plus, 41.1 ± 10.1 versus 42.3 ± 6.0 MPa. Mode of failure analysis for Clearfil tri-S Bond revealed an equal distribution between the three types of failure, and the predominant mode of failure was adhesive for One-Up Bond F Plus. FE-SEM observations of dentin to which adhesive had been applied revealed that the smear layer had been removed and the collagen fibers exposed. (J. Oral Sci. 49, [183][184][185][186][187][188][189] 2007)

The purpose of this study was to evaluate the influence of irradiation time on volumetric change and flexural properties of flowable resins. Four commercially available flowable resins were employed. For volumetric shrinkage measurement, resin pastes were inserted into a mold (2 mm in height, 4 mm in diameter) and put into a water-filled dilatometer. This was followed by light irradiation for 10, 20, or 30 seconds at 600 mW/cm 2 . Volumetric shrinkage of the specimens was then determined from the change in the height of water meniscus, and the percentage volumetric change thereof was calculated. For flexural strength measurement, resin pastes were filled into a stainless steel mold (25×2×2 mm), and the middle one-third of the specimen was first irradiated. The remaining two-thirds were irradiated under the same irradiation conditions as volumetric shrinkage measurement. After 24-hour storage in 37℃ water, three-point flexural tests were performed with a span length of 20 mm at a crosshead speed of 1.0 mm/min. One-way ANOVA followed by Tukey' s HSD test were used for statistical analysis. For all materials tested except Estelite Flow Quick, both volumetric shrinkage and flexural strength increased with longer light irradiation time. Results of this study indicated that both volumetric shrinkage and flexural properties were influenced by light irradiation time and resin composite type.

SUMMARYThis study was carried out to examine the effect of storage conditions of adhesive vials on the dentin bond strength of single-step self-etch adhesive systems. The adhesive/resin composite combinations used were: Absolute 2/Ceram·X(AB), Adper Prompt L-Pop/Filtek Supreme(AP), Bond Force/Estelite Σ Σ Quick(BF), Clearfil tri-S Bond/Clearfil AP-X(CT) and GBond/Gradia Direct(GB). Vials of adhesives were stored at 5°C, 23°C or 40°C. Specimens for the dentin bond strength tests were made after 0, 1, 2, 3, 4, 5 and 6 months. Labial bovine mandibular incisor dentin was wet ground with #600 SiC. The adhesives were applied according to the manufacturer's instructions. After adhesive light irradiation, resin composite cylinders were created (4 mm x 2 mm) and polymerized (n=10). Samples were stored in 37°C distilled water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/minute. ANOVA and Dunnet tests were performed at a significance level of 0.05. Scanning electron microscopic (SEM) observations of the dentin surfaces were made. Bond strengths varied, with storage conditions ranging from 2.2 ± 1.4 to 9.3 ± 2.4 MPa for AB, 4.5 ± 1.5 to 13.3 ± 2.7 MPa for AP, 5.1 ± 1.9 to 5.1 ± 1.9 MPa for BF, 7.7 ± 1.9 to 19.7 ± 2.0 MPa for CT and 7.4 ± 1.3 to 15.7 ± Clinical RelevanceShort-term storage at low temperatures enhances the dentin bond strength of single-step selfetch adhesives. Laboratory Research

The purpose of this study was to investigate the development of shear bond strength of resin composites using self-etching primer systems. Four different types of self-etching primer systems with different combinations of their recommended resin composites were used. Bovine incisors were mounted in self-curing resin and the facial surfaces were wet ground on #600-SiC paper to expose the dentin. The shear bond strengths of ten samples per test group were measured at a crosshead speed of 1.0 mm/min after storage for 5, 10, and 60 min, and 24 h in distilled water at 37 degrees C. One-way ANOVA followed by Dunnett's test (alpha = 0.05) was used to examine the significance of differences between the mean bond strength at 24 h and each of the other storage periods. The dentin bond strengths of all the materials tested increased with prolonged storage time. Such differences in the changes in bond strength might have clinical implications if a restoration is subjected to high stress immediately after it has been placed. It is important to consider the development of dentin bond strength to allow the materials sufficient maturation time prior to functional loading or application of other forms of external stress.