Effect of enamel shades on color of layered resin composites

The purpose of this study was to evaluate the effect of the covering enamel layer of various thicknesses on the color of layered resin composites (LRC). To this end, the CIELAB parameters of the following were evaluated: underlying base (ULB: 2.0 mm of body shade + 3.0 mm of opaque shade), inherent color of the enamel shade (4.0 mm of enamel shade + ULB), and LRC disks (0.5, 1.0, 2.0, 3.0 mm of enamel shade + ULB) of Filtek Supreme (FS, 3M) and Gradia Direct (GD, GC). To assess the effect of the enamel layer on the color of LRC, color difference between ULB and LRC was calculated. With FS, the enamel layer had no major effect on the color of LRC - regardless of thickness. With GD, the enamel layer had a significant effect on the color of LRC, even if the thickness was only 0.5 mm. The difference in enamel layer effect between the two products could be attributed to the difference in color characteristics of the two enamel shades

The effects of different application time on all-in-one self-etching adhesives

The purpose of this study was to evaluate the effects of different application times in all-in-one systems on micro-tensile bond strength. Three all-in-one systems, EB （Easy Bond, 3M ESPE, St. Paul, MN, USA）, BB （BeautiBond, Shofu Inc., Japan） and BF （BondForce, Tokuyama Denetal, Ibaraki, Japan）were used with four different application times: 10s, 20s, 30s, and 40s. Bond strengths to dentin were determined using μTBS test after 24h of water storage at 37℃. In addition, an evaluation of both resin-dentin interface, and fractured surface on dentin side was performed by SEM. The maximum μTBS for each system was observed with a 20s application time. There was no positive correlation between the thickness of hybrid layers and application time, which meant hybrid layers did not increase in thickness along with the increase in application time, rather a difference of quality was detected. Prolonged application time affected the adhesive strength of all-in-one systems, and they were mostly effective for the 20s application time

Bonding Performance of a Hydrophilic Amide Monomer Containing Adhesive to Occlusal and Cervical Dentin

This study aimed to evaluate the bonding performance of a new one-step self-etching adhesive system containing a novel hydrophilic amide monomer. Clearfil Universal Bond Quick (CUB) and Clearfil Megabond 2 (CMB) were used as the one-step and two-step adhesive systems, respectively. Flat dentin surfaces of human premolars were exposed using #600 SiC (silicon carbide) and bonded with the respective adhesives of each system. The teeth were sectioned to obtain beams (1 mm x 1 mm) after 24 h of water storage. The mean bond strength and standard deviations (MPa) on an occlusal surface were as follows: CUB: 45.9 +/- 19.7 and CMB: 67.9 +/- 25.3. The values for cervical ones were CUB: 56.0 +/- 20.3 and CMB: 67.6 +/- 16.0, respectively. In both conditions, the microtensile bond strength (mu TBS) value was lower than that of CMB. As seen during the microscopic observation, no adhesive failure was observed after mu TBS testing because CUB formed a firm and tight adhesive interface

Effect of application time of colloidal platinum nanoparticles on the microtensile bond strength to dentin

The purpose of this study was to investigate the effect of application time of colloidal platinum nanoparticles (CPN) on bond strength. Dentin surfaces were subjected to one of the following treatments: (A) Etching with 10% citric acid-3% FeCl3 solution (10-3 solution); (B) Etching with 10-3 solution followed by applying CPN as a primer solution for 10, 20, 30, or 60 seconds; and (C) Priming with CPN for 10, 20, 30, or 60 seconds followed by etching with 10-3 solution. An acrylic rod was bonded to each treated dentin surface using 4-META/MMA-TBB resin. Bonded specimens were sectioned into beams for microtensile bond strength testing. In groups (B) and (C), highest bond strength was obtained when dentin surfaces were treated with CPN for 30 seconds. This meant that the CPN primer solution either enhanced the penetration of resin into dentin or the degree of conversion of 4-META/MMA-TBB resin. Within the limitations of this study, treatment with 0.1 mN CPN primer solution followed by 20 seconds of water rinsing resulted in high bond strength

Hybrid layer seals the cementum/4-META/MMA-TBB resin interface

Although 4-META/MMA-TBB resin has adhesive properties to dentin, and has been clinically used for the bonding treatment of vertically fractured roots and apicoectomy, there has not been any investigation on the adhesion of 4-META/MMA-TBB resin to cementum. The purpose of this in vitro study was to evaluate the bonding and the sealing ability of 4-META/MMA-TBB resin to cementum. Bovine root cementum and dentin surfaces were treated with a citric acid and ferric chloride solution, and the 4-META/MMA-TBB resin was applied on the treated surfaces before testing. The microtensile bond strength and the leakage levels obtained for the cementum were almost equal to those for the dentin. In SEM and TEM observations, a hybrid layer approximately 2-3 μ in thickness was observed at the interface between the resin and the cementum. It is concluded that 4-META/MMA-TBB resin adhered to cementum via a hybrid layer on cementum, as previously reported for dentin. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 200

Hydrolytic Stability of One-step Self-etching Adhesives Bonded to Dentin

Purpose: To evaluate the hydrolytic stability of three one-step self-etching adhesives (1-SEAs) bonded to dentin through bond strength testing and ultra-morphological interfacial analysis before and after long-term thermocycling.status: publishe

NaOCl degradation of a HEMA-free all-in-one adhesive bonded to enamel and dentin following two air-blowing techniques

OBJECTIVE: Phase-separation within HEMA-free all-in-one dental adhesives may result in the entrapment of droplets within the adhesive resin. Strongly air-blowing prior to polymerization, can remove most of these droplets. The objective of this study was to evaluate the effect these droplets may have on the resistance of the adhesive-tooth interface to NaOCl degradation. METHODS: The micro-tensile bond strength (muTBS) to enamel and dentin was determined when a HEMA-free all-in-one adhesive was applied either following a mild or strong air-blowing technique. The bonds were also exposed to an aqueous sodium hypochlorite (NaOCl) solution for 1h, following a recently introduced methodology to mimic in vivo bond degradation. RESULTS: This study revealed that strong air-blowing of the adhesive only resulted in a significantly higher micro-tensile bond strength (muTBS) to dentin, but not to enamel. Likewise, NaOCl only reduced the muTBS to dentin for both the mild and strong air-blowing technique, but again not the muTBS to enamel. Failure analysis by SEM clearly revealed that strong air-blowing is less effective in droplet removal when the adhesive was applied in small and narrow class-I cavities, as compared to when it was applied to flat surfaces. CONCLUSIONS: NaOCl did preferentially dissolve the hybrid layer at dentin, and more for the mild than for the strong air-blowing technique. A strong air-blowing procedure resulted in a more NaOCl-resistant hybrid layer, so that it can be concluded that a HEMA-free one-step adhesive definitely benefits from a strong air-blowing technique.status: publishe