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Objective@# To explore the effect of ultrasound on dentin smear layer's surface and bonding strength of the universal resin adhesive under self-etching mode. @*Methods@# Forty mandibular third molars without caries were randomly divided into two groups; one was polished with silicon carbide sandpaper; the other was polished with silicon carbide sandpaper followed by ultrasonic treatment. Scanning electron microscope (SEM) was used to observe surface of the dentin. Treated teeth were bonded with two universal resin adhesives, Clearfil Universal Bond (pH=2.3) and All-Bond Universal (pH=3.1), and the penetration of the bonding interface was observed with a confocal laser scanning microscope (CLSM) after Rhodamine B staining. Finally, the micro tensile bond strength test was conducted to test the adhesion. @*Results@# The SEM showed that after polishing with silicon carbide sandpaper, the smear layer of the dentin surface was scratched, and dentin tubules were almost completely blocked, with no obvious dentin tubules exposed. After ultrasonic treatment, the scratches were reduced, and a large number of dentin tubules were exposed. CLSM showed that both adhesives could penetrate the dentin along the dentin tubules more deeply after ultrasound treatment. Micro tensile bond strength tests showed that ultrasonic treatment could enhance the bonding strength of two universal resin adhesives. However, there was no statistical difference in bonding strength between these two universal resin adhesives under the same treatment. .@*Conclusion@# Ultrasound can partially remove the smear layer on dentin's surface, expose dentin tubules, and increase universal resin adhesives' penetration depth and bonding strength under self-etching mode
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BACKGROUND: When the tooth surface is treated with a rotary or manual instrument, a smudge layer is formed on the enamel and dentin by debris generated by cutting and abrasion. The bonding interface between the adhesive and the dentin is considered as a weak part in the direct repair process. To clarify the effect of smear layer on different kinds of adhesive is significantly important for dentists to select and correctly use the adhesive in clinical treatment. OBJECTIVE: To evaluate the effect of different diamond burs on the dentin bonding performance of four adhesive systems to dentin after 24 hours and 100 days of artificial saliva-storage. METHODS: Adhesive systems were: (1) VSA (Optibond Versa, Kerr); (2) AIO (Optibond All in One, Kerr); (3) SBU (Single bond Universal, 3M); (4) GLU (Bond 5, Gluma, Heraeus). In present study, 80 extracted human molars were randomly divided into four groups and each group is divided into 4 subgroups. Dentin surfaces were prepared by: (1) 600-grit SiC-paper (control group); (2) super-fine diamond bur; (3) regular diamond bur; (4) coarse diamond bur. Bonding agent was applied according to each manufacturer’s instruction. After light-curing, dentin surfaces were built-up with resin composite (A2, CHARISMA, Heraeus). The micro-tensile bond strength was determined after 24 hours and 100 days of storage in artificial saliva at 37 °C. The fractured surfaces on dentin side were observed by scanning electron microscope. RESULTS AND CONCLUSION: (1) Storage for 24 hours: There was no significant difference among groups under VSA and GLU. Under SBU and AIO, the bond strength in the coarse diamond bur group was significantly lower than that in the control group (P 0. 05). Using coarse diamond bur, the bond strength in the VSA group had significant difference compared with the AIO, GLU and SBU groups (P 0. 05). (2) Storage for 100 days, there was no significant difference among groups under VSA and GLU. Under SBU, the bond strength in the coarse diamond bur group was significantly lower than that in the control group (P 0. 05). Using regular diamond bur, the bond strength showed no significant difference in the GLU group compared with the SBU, and VSA groups (P > 0. 05). Using coarse diamond bur, the bond strength had no significant difference between VSA and AIO groups (P < 0. 05). (3) Using VSA, the bond strength in each group at 100 days showed significant difference compared with that at 24 hours (P < 0. 05). (4)Compared with immersed for 24 hours, the ratio of bond interface and combined crack in the VSA, SBU and GLU groups after immersed for 100 days was increased, especially the VSA group. Compared with the other groups, the ratio of bond interface and combined crack in the GLU group after immersed for 24 hours and 100 days both increased by 50%. (5) These results indicate that preparation by different burs produces different smear layers, which has significant effect to self-etching adhesive system and has no significant effect to total-etching adhesive system. Storage time makes effect on different adhesives.
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Objectives: The objective of the present study is to evaluate the bond strength of: (a) Zirconia blocks (tribochemical treatment and zirconia primer) and resin blocks bonded using self-adhesive resin cement (phosphate monomer cement). (b) Zirconia blocks and resin blocks bonded using nonphosphate monomer cement. (c) Micro-tensile bond strength of zirconia and resin blocks, bonded with self-adhesive resin cement and nonphosphate monomer cement after thermocycling. Materials and Methods: Twenty zirconium-dioxide specimens (5 mm × 5.4 mm × 13 mm) were produced using a metal mold. Each zirconium block was duplicated in light-curing resin material specimen (5 mm × 5.4 mm × 13 mm) using a mold made of addition silicon impression material. A total of 40 specimens were made, of which 20 specimens were zirconia blocks and 20 were resin blocks, which would be bonded to each other using phosphate monomer-containing cement (Multilink [10 nos.]) and nonphosphate monomer-containing cement (RELY-X [10 nos.]). The specimens were then divided into two groups of n = 10 each. The surface of zirconium specimen of one group (Group 1) was treated with zirconia primer and bonded with phosphate monomer-containing cement, and the other groups (Group 2) were not treated with any surface conditioning and were bonded with a nonphosphate containing cement. The specimens in each group were further subdivided into two subgroups of n = 5 each as follows: Group 1-1A (subjected to thermocycling), 1B (nonthermocycled) and Group 2-2A (subjected to thermocycling), 2B (nonthermocycled). Then, they were subjected for testing of tensile bond strength under a universal testing machine. Results: Resin cement selection seems to be a more relevant factor in the bonding of zirconia. The phosphate monomer-containing cement has the better bond strength after thermocycling compared to the nonphosphate monomer group. Thermocycling reduced the bond strength of both the groups and a significant difference was seen in the bond strength of nonphosphate monomer cement group subjected to thermocycling compared to the nonthermocycled one. Tensile bond strength values were significantly affected by the luting agent system employed and by thermal aging. Hence, for long-term durability, luting of zirconia with a phosphate monomer-containing cement after the zirconia has been surface treated is preferable as their bond strength did not show much significant difference after being subjected to thermocycling, compared to the nonthermocycled group. Conclusion: Resin cement selection seem to be a more relevent factor in the bonding of zirconia thermocycling does affect adhesion to to zirconium oxide ceramics.
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The purpose of this study was to evaluate the effect of multiple application of all-in-one dentin adhesive system on microtensile bond strength using confocal laser scanning microscope and microtensile bond strength test. Flat occlusal dentin surfaces were prepared using low-speed diamond saw. In group I, Scotchbond Multipurpose (SM) was applied by manufacturer's recommendation. In group II, after Adper Prompt L-Pop was applied for 15s and light cured for 10s, the second coat was re-applied and light-cured. In group III, after light-curing the second layer, the third coat was re-applied and light-cured. Specimens bonded with a resin-composite were sectioned into resin-dentin stick for measuring the adhesive layer thickness by confocal laser scanning microscope and evaluating micro-tensile bond strength. The adhesive layers of three-step dentin adhesive system, 3 coats of Adper Prompt L-Pop had significantly thicker than SM, 2 coats of Adper Prompt L-Pop (p 0.05). And SM, 3 coats of Adper Prompt L-Pop had significantly higher than 2 coats of Adper Prompt L-Pop in bond strengths (p < 0.05).
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Adhesives , Dentin , DiamondABSTRACT
0.05),respectively.The fractured adheisive dentin surface was mainly a mixed failue mode.Conclusions:There is no significant difference in the bond strengths of each of the three bonding agents to ND and CAD.
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Objective:To evaluate the influence of delayed application of mixed self-etching bonding agent on the tensile bond strength.Methods:Two "two-bottle,one-step" self-etching adhesives,Adper Prompt and Xeno III,were evaluated.The occlusal enamel of human third molar was cut out and the exposed dentin surface was divided in two halves by a 1 mm deep groove in the labial-lingual orientation to allow for evaluation of immediate application and delayed application(0.5,1,2,3,4,5 and 6 h) of mixed self-etching bonding agent in the same specimen,followed by composite resin built-up on the adhesive.The bonded specimens were sectioned into beams of approximately 0.9 mm2 and subsequently subjected to micro-tensile bond strength testing at a crosshead speed of 1.0 mm/min.Results:The specimens bonded with the Adper Prompt within 5 h after mixing showed no different and that with the Xeno III within 3 h after mixing showed no different.Conclusion:The effective period for "two-bottle,one-step" self-etching adhesives after mixing is limited.Different bonding agents have different effective periods.