BACKGROUND:At present, there are stil differences in the studies of total-etch, self-etch and self-bonding resin cement effect on the coronal microleakage and bonding strength of fiber posts.
OBJECTIVE:To evaluate the coronal microleakage and the bonding strength of fiber posts treated with three kinds of resin cements.
METHODS:Total y 32 upper incisors were randomly divided into five groups, including three experimental groups and two control groups. After the root canal preparation, three kinds of resin cements (EMBRACE WetBond, LuxaCore, Medental Multi-cure) were used to fiber posts with the bond diameter of 1.4 mm. Stereomicroscope was used to observe the microleakage. Then, the specimens were cut into 2 mm wafer along the axis of tooth, and universal testing machine for push-out test was used to observe the failure mode. In the positive control group, no root canal preparation was done, the root was coated with nail polish, and the crown was directly exposed to the dye. In the negative control group, no root canal preparation was done, the root canal orifice was covered with the resin, the tooth was overal coated with nail polish and then embedded 1 mm below the section.
RESULTS AND CONCLUSION:The microleakage was observed in al the three resin cements, Medental Multi-cure showed the least microleakage and LuxaCore showed the largest microleakage, and there was significantly different among the three kinds of resin cements (P<0.05). The bonding strength of three cements had significant differences (P<0.05), and ranked from high to low:Mdental Multi-cure, LuxaCore, and EMBRACE WetBond. The main fracture modes were binder/fiber post fracture and mixed failure. The results suggest that the total-etch resin cement binds tightly with the dentin, and owns a superiority in the microleakage and bonding property as compared with the self-etch resin cements and self-bonding resin cements.

Biotinylated chitosan nanoparticles (Bio-CS-NP) were prepared for the active delivery to cancer cells and its characterization was investigated in this study. The preparation process included two steps. First, biotinylated chitosan ( Bio-CS ) was obtained through a reaction between sulfosuccinimidobiotin and chitosan (CS). Second, Bio-CS-NP were prepared by the precipitation of Bio-CS with sodium chloride solution. With a biotin reagent box, the conjugation densities of biotin on the surface of Bio-CS-NP were determined. The morphology and diameter of the nanoparticles were assayed by transmission electron microscope (TEM) and laser light scattering particle analyzer, respectively. The uptake of nanoparticles by human hepotacarcinoma HepG2 cells, for example, Bio-CS-NP and chitosan nanoparticles (CS-NP) without any modification, was quantitatively examined. The results indicated that the conjugation densities of biotin on the surface of Bio-CS-NP were 2.2 biotin CS. Bio-CS-NP were spherical, smooth on the surface. The average diameter was 296.8 nm. The polydispersion index was 0.155. The uptake of Bio-CS-NP by HepG2 cells was much higher than that of CS-NP (P < 0.05). It demonstrated that Bio-CS-NP can be applied as a new vehicle to actively deliver anticancer drugs to tumor cells. The method for the determination of biotin was simple and practical.
Biotin ; analogs & derivatives ; chemistry ; metabolism ; Biotinylation ; Carcinoma, Hepatocellular ; metabolism ; pathology ; Cell Line, Tumor ; Chitosan ; chemistry ; metabolism ; Drug Carriers ; Drug Compounding ; Drug Delivery Systems ; Humans ; Liver Neoplasms ; metabolism ; pathology ; Nanoparticles ; Particle Size ; Succinimides ; chemistry ; metabolism