Does the bonding effectiveness of a fiber post/resin composite benefit from mechanical or chemical treatment? Seven methods for saliva-contaminated surfaces.

PURPOSE: This study examined four cleaning methods and three chemical treatments for artificial saliva-contaminated fiber posts in terms of bonding durability to resin composite core materials. METHODS: Non-contaminated fiber posts (Tokuyama FR Post, Tokuyama Dental) and those contaminated (GC Fiber Post, GC) with artificial saliva (Saliveht Aerosol, Teijin Pharma) were used. Washing and drying (WD), alcohol cleaning (AlC), H3PO4 etching (P/WD), alumina blasting (B/D) for decontamination and silanization (Clearfil Ceramic Primer Plus, Kuraray Noritake Dental, Si), resin priming (HC Primer, Shofu, MMA), and bonding resin application (Clearfil Universal Bond Quick, Kuraray Noritake Dental, BR) for chemical treatment were performed. The treated fiber post was planted inside a cylindrical tube and filled with resin composite (DC Core Automix ONE, Kuraray Noritake Dental). The specimen was sectioned, and a push-out test was performed after 24 h, 1 month, and 3 months. The fracture surface was observed using a scanning electron microscope (SEM). RESULTS: Adhesion between the non-contaminated fiber post and resin composite did not improve by silanization and decreased by alumina blasting. SEM observations revealed a fractured glass fiber by alumina blasting. Saliva contamination decreased the bond strength between the fiber post and resin composite; however, recovery was achieved by WD, Alc, P/WD, and B/D. Compared to Si, BR (P = 0.009) was effective in restraining the long-term durability of bonding, whereas MMA (P = 0.99) was not. CONCLUSION: The application of bonding resin after alcohol cleaning is the most convenient and effective clinical procedure for fiber post surface treatment.

Bovine colostral antibody against verotoxin 2 derived from Escherichia coli O157:H7: resistance to proteases and effects in beagle dogs.

A bovine colostral antibody against verotoxin (VT) 2 of Escherichia coli O157:H7 was administered orally to beagle dogs. The antibody remained in the dogs' small intestine for at least 2 h, whereas little serum antibody remained 1.5 h after administration. Furthermore, the antibody activity of secretory IgA did not change until 2 h after administration; however, the activity of IgG and IgM antibodies decreased by approximately 60% and 40% at 2 h after administration, respectively. Seven beagle dogs inoculated with Escherichia coli O157:H7 producing VT2 were administered bovine colostral antibody or bovine colostral whey without antibody. With administration of bovine colostral whey without antibody, the amount of VT2 in feces decreased gradually after administration and increased again at 5 d after inoculation, whereas bovine colostral antibody significantly reduced the amount of VT2 in feces on the day after administration. In addition, 9 beagle dogs were given bovine colostral antibody, bovine plasma antibody, or saline. The amount of VT2 in feces again decreased significantly more rapidly after administration of bovine colostral antibody than after administration of bovine plasma antibody or saline.

Screening study for repeated dose and reproductive/developmental toxicity of rubber accelerator, N,N-dicyclohexyl-2-benzothiazolesulfenamide, in rats.

A screening study for a vulcanization accelerator N,N-dicyclohexyl-2-benzothiazole-sulfenamide (DCBS) was performed in rats. Rats were given DCBS by gavage daily at 0, 6, 25, 100, or 400 mg/kg. Males were dosed for a total of 44 days beginning 14 days before mating. Females were dosed for a total of 40-51 days beginning 14 days before mating to day 3 of lactation. Toxicologic changes were significantly noted only at 400 mg/kg. Three females died. An increased incidence of females showing decreased locomotor activity, soil of the lower abdominal fur, and reddish tears was observed. A lowered body weight was found in males and females. Increased urinary ketones and serum inorganic phosphorus and decreased serum glutamate pyruvate transaminase in males were found. Increased absolute and relative weights of the kidneys in males and decreased absolute weight of the thymus in both sexes were noted. Significant fatty degeneration of the renal tubular epithelia, vacuolation of the adrenocortical cells, and atrophy of the spleen were observed in females. Significant decreases in the gestation index, numbers of corpura lutea, implantations, pups born and pups born alive, live birth index, and viability index were detected. It is concluded that the No Observed Adverse Effect Levels (NOAELs) for repeat dose and reproductive/developmental toxicity are 100 mg kg-1 day-1 in this screening study.

Neutralizing activity of bovine colostral antibody against verotoxin derived from enterohemorrhagic Escherichia coli O157:H7 in mice.

The neutralization efficacy of bovine colostral antibody against verotoxin (VT) 1 and 2 was investigated. Cows were immunized with VT1 or VT2 fourteen times at 7-day intervals. A colostral antibody exhibiting high titers was obtained from immunized cows. Survival rates were evaluated in mice administered VT1 or VT2, and those infected with Escherichia coli (E. coli) O157:H7 producing VT1 or VT2. Survival rates after VT1 administration were 100% in the single-administration group, 90% in the repeat-administration group, and 78.6% in the control group. Survival rates after VT2 were 75.0% in the single-administration group, and 100% in the repeat-administration group. All mice in the control group died. Colostral antibody and fosfomycin (FOM) in the colostral antibody group and FOM and skim milk in the control group were administered three times per day for 5 days to mice infected with E. coli O157:H7 producing VT1 or VT2. Survival rates after inoculation with E. coli O157:H7 producing VT1 were 80.0% in the colostral antibody group, and 63.6% in the control group. Survival rates after inoculation with E. coli O157:H7 producing VT2 were 83.3% in the colostral antibody group, and 20.0% in the control group. The survival rate in mice without treatment following inoculation with E. coli O157:H7 producing VT2 was 88.2%. The survival rates in mice infected with E. coli O157:H7 strains producing VT1 or VT2 improved after administration of this colostral antibody, which exhibited neutralization efficacy against VT.