Resin-based pit-and-fissure sealants are often used to form a barrier on the occlusal surface of molars to treat caries lesions; however, bacteria can remain in the pit and fissures without detection, increasing the risk of secondary caries. Sealants with antimicrobial properties or microbial repellent actions might be advantageous. The aim of this study was to assess the inhibitory effect of a 2-methacryloxylethyl dodecyl methyl ammonium bromide (MAE-DB)-incorporated sealant against Streptococcus mutans. MAE-DB (4% wt) was incorporated into a commercially available sealant, Eco-S resin-based pit-and-fissure sealant (Vericom Co., Ltd., Korea); a sealant without MAE-DB served as a negative control, and Clinpro™ Sealant (3M™ ESPE™), a fluoride-releasing resin, was used as a commercial control. The effects of the cured sealants and their eluents on the growth of S. mutans were determined according to colony-forming unit counts and metabolic tests. The effects of the cured sealants on the adherence and membrane integrity of S. mutans were investigated using confocal laser-scanning microscopy (CLSM) in conjunction with fluorescent indicators. Compared with the negative control and commercial control, the cured MAE-DB-incorporated pit-and-fissure sealant exhibited a significant inhibitory effect on the growth of S. mutans (P < 0.05), whereas the eluents did not show any detectable antibacterial activity. The commercial control also showed no detectable bactericidal activity. Moreover, the aged experimental material retained its property of contact inhibition of biofilm formation. The fluorescence analysis of CLSM images demonstrated that the cured MAE-DB-incorporated sealant could hamper the adherence of S. mutans and exert a detrimental effect on bacterial membrane integrity. The incorporation of MAE-DB can render a pit-and-fissure sealant with contact antibacterial activity after polymerization via influencing the growth, adherence, and membrane integrity of S. mutans. Therefore, MAE-DB-containing pit-and-fissure sealant shows promise for preventing or controlling dental caries on occlusal pit and fissures of molars.

No abstract

The present study was conducted to investigate the effects of dietary supplementation of selenium from different sources on the growth performance, nutrient digestibility, and blood immune indices of piglets orally challenged with Salmonella typhimurium (ST). In a 2 × 2 factorial arrangement, 32 piglets (6.43 ± 0.54 kg of body mass) were assigned into four groups with or without dietary inclusion of sodium selenite (SS) or yeast selenium (YS) and with or without ST challenge (5 ml 1 × 109 cfu/ml ST or 5 ml saline) on d 13. In each period, YS increased average daily feed intake and average daily gain but did not reach statistical significance. During the challenged stage, piglets fed YS had higher digestibility of dry matter, crude protein, crude fat, and YS reduced the amount of Escherichia coli in feces. Additionally, YS regulated the composition of T-lymphocyte subset and influenced the production of inflammatory cytokines. In conclusion, in this study selenium-enriched yeast was more effective in enhancing nutrient digestibility, and inhibiting inflammation and oxidative stress by inducing the activity of the lymphocytes, expression of antioxidant enzymes and so on.

No abstract

No abstract