The purpose of this study was to evaluate the effect of immediate or delayed composite resin filling on dentinal microtensile bond strength (µTBS) after applied the adhesive.

The coronal dentin of human third molars was exposed. Single-Bond or One-Step was applied on the dentin surfaces, and composite resin were constructed immediately (group 1) or 5 min., 10 min., 15 min., 20 min. and 30 min. (groups 2-6) after an adhesive was applied. The specimens were sectioned and made bar-shaped. Each surface area of them was about 1mm². The µTBS test was performed by EZ test. The results were analysed by One-way ANOVA and Tukey's test at 95% significance level.

The results suggested that the µTBS of Single-Bond to dentin was decreased when the composite resin was constructed 20 min. and 30 min. after Single-Bond was applied. But the µTBS of One-Step was not affected by delayed composite resin filling.

This study evaluated the microleakage and interfacial gap between enamel and composite resin under the dry and wet condition of the enamel surface. V shaped class 5 cavities were prepared on the occlusal portion of extracted human molars. Samples were divided into three groups: D group (air dry for 10-15 s), BD group (blot dry with moist cotton pellet), and DR group (air dry for 10-15 s and rewet with Aqua-Prep F for 20 s).

Cavities were filled using Aelitefil composite resin after applied One-Step. Microleakage was tested by 2% methylene blue dye solution and the data were statistically analysed by Kruskal-Wallis test and Mann-Whitney test. Also Enamel-resin interface was observed under SEM. Group BD showed statistically lower microleakage than group D (p < 0.05), but there was no statistically significant difference between group BD and DR (p > 0.05). At the enamel-resin interface, group D showed the gap of 2 µm thickness, but group BD and DR showed close adaptation.

In conclusion, the use of blot dry and rewetting agent (Aqua-Prep F) resulted in decreased microleakage and improved adhesion between enamel and resin when using One-Step.

This study evaluated the marginal microleakage of five single step adhesives. Class V cavity preparations with occlusal margins in enamel and gingival margins in dentin were prepared on both buccal and lingual surfaces of extracted human molar teeth. Prepared teeth were randomly divided into five groups and restored using one of the single step adhesives and composite resins: Prompt L-Pop/Filtek Z-250 (Group 1), AQ Bond/Metafil CX (Group 2), One-Up Bond F/Palfique Toughwell (Group 3), Futurabond/Admira (Group 4), Xeno III/Spectrum TPH (Group 5).

The restored teeth were thermocycled. Microleakage was assessed by dye penetration using 2% methylene blue dye solution. The teeth were bisected buccolingually and evaluated for microleakage under steromicroscope. The data were statistically analysed by Kruskal-Wallis test and Mann-Whitney tests.

The results of this study were as follows;

Microleakage of enamel margins in group 3 was statistically higher than that in groups 1, 2, 4, 5 (p < 0.05).

In conclusion, Prompt L-Pop showed the least leakage at enamel margin, and AQ Bond showed at dentin margin in this study. Marginal miroleakage in dentin was higher than that in enamel.

This study investigated that the effect of rewetting agent on dentinal microtensile bond strength (µTBS). Human molars were sectioned to expose the superficial dentin surfaces.

Samples were divided into two groups according to type of adhesives-Single Bond (S) and One-Step (O)], and again subdivided into five groups by different dentin surface treatment-dry for 15s (D), blot dry (BD) or dry for 15s, and rewet with different rewetting agents [distilled water (DW), Gluma Desensitizer (GD) and Aqua-Prep (AP)] for 30s. After application of adhesive, composite resin was built up on the bonding surface. Each tooth was sectioned to obtain stick with 1 mm² cross sectional area and the µTBS was determined by EZ test.

In the S group, the mean µTBS of GD, AP and BD group was significantly higher than that of DW and D group (p < 0.05). In the O group, the mean µTBS of AP, GD, BD and DW group was significantly higher than that of D group (p < 0.05).

The data suggested that Gluma Desensitizer and Aqua-Prep could be successfully used as rewetting agents, and Distilled water could be acceptable in aceton based adhesive system only.

The purpose of this study was to compare the microhardness and the fluoride content of enamel and dentin around fluoride- or non fluoride-containing restorations. Forty extracted human teeth were used and prepared cervical cavities on proximal surface. Experimental teeth were divided into five groups. Group 1 : Prime & Bond NT and Z100, Group 2 : Prime & Bond NT and F2000, Group 3 : Scotchbond Multi-Purpose and Z100, Group 4 : Scothcbond Multi-purpose and F2000, Group 5 : Fuji II LC. The cavities were filled with dentin adhesives and restorative materials. After each tooth was bisected, one half was tested microhardness and the other half was analyzed the fluoride at the enamel and dentin by an EPMA-WDX device. The results were as follows:

1. There was no statistical difference among the microhardness of enamel surface in all group.

2. The microhardness at dentin of 100 µm point in Group 2 and 20 µm point in Group 4 was lower than that of normal dentin (p>0.05).

3. There was no statistical difference among the fluoride content of enamel surface in all group.

4. The fluoride content at the dentin of 30 µm point in Group 2 and 5 were higher than those at 100 µm and 200 µm point in Group 2 and normal dentin (p<0.05).

5. At the dentin of 30 µm point, Group 2 showed higher fluoride content than Group 1 and 3, and Group 5 showed higher fluoride content than other groups.

This study evaluated the influence of application time of self-etching primers on microtensile bond strength (μTBS) to dentin using three self-etching primer adhesive systems.

Dentin surfaces were exposed from forty-eight human molars. They were conditioned with three self-etching primers (Clearfil SE Bond [SE], Unifil Bond [UF], Tyrian SPE + One Step Plus [TY]) and different primining times (10s, 20s, 30s and 40s). Composite resins were bonded to dentin surfaces and specimens were made. μTBS was tested and statistically compared using by one-way ANOVA and Tukey’s Test.

The results of this study presented that priming time for 10s in SE and UF groups and for 30s and 40s in TY group was highly decreased μTBS to dentin.