[Retention of fissure sealants used with enamel and dentin bonding agents]

Tooth decay is the most common chronic disease. Fissure sealant therapy is among the suitable treatments to prevent occlusal caries. The ability of fissure sealant to prevent pit and fissure caries is due to the sealant retention. Considering the fact that several bonding agents are available in the market, clinical studies are required to assess the durability of sealants after using bonding agents. The purpose of this study was to compare the durability of fissure sealants bonded with dentin and enamel bonding agents after 12 months. A total of 30 healthy 6 to 12 year-old patients presenting with at least one caries-free, fully erupted molar tooth at each side of their mandible were selected. All fissures of 60 molars were sealed using the following two techniques: Group1: acid etchant + Single Bond [3M, ESPE] dentin bonding agent +Eco-S [VERICOM]; group 2: acid etchant + Margin Bond [Coltene/Whaledent AG] enamel bonding agent +Echoseal sealant. Cotton roll isolation was used in both groups. Sealants were evaluated 12 months after placement. Data were analyzed using Wilcoxon test. There was no significant difference between the two examined groups. Clinical success was 60% in group 1[dentin bonding agent] and 56.66% in group 2 [enamel bonding agent]. Although no significant difference was found between the two groups, it seems that bonding agents with hydrophilic groups show more favorable results especially when appropriate isolation is not achieved

[Alterations to antioxidative enzymes in early life stages of rainbow trout [Oncorhynchus mykiss] reared in different densities]

Stocking density induced stress that affects energy intake, growth rate, enzymatic activity and oxygen consumption in fish. In this study the development of antioxidant enzyme Glutathione peroxidase [GPX], catalase [CAT] and superoxide dismutase [SOD] in egg and larvae of rainbow trout [Oncorhynchus mykiss] that kept in different stocking density was investigated. Four groups of eggs, cultured in pans [size16x9.5x10 cm, volume 10 L] with density of 400egg/l [group1 as routine density], 200egg/l [group2 as low density] and 600egg/l [group3 as high density] in triplicate. Eggs were held in tanks supplied with flow-through freshwater at 10.8[degree sign]C. samples were taken at day1 [fertilization], 3 [Cleavage], 8[organogenesis], 16 [eyed egg], 31 [hatch] and 48 [active feeding]. A significant increase in GPX and SOD activity was seen from fertilization till eggs were eyed. [p<0.001]. The activity of these enzymes decreased to active feeding [p<0.001], meanwhile this activity was higher than the fertilization starts. Similar changes were seen in SOD and GPX activities in higher and lower densities [Group 2, 3]. CAT activity increased from fertilization to organogenesis and then toward active feeding significantly decreased in compare to fertilization [p<0.001]. Pattern of changes of catalase activity in high density group was similar to routine density but in low density group it was higher until eggs were eyed. GPX, SOD and CAT activities did not show significant difference in similar days among different groups [p<0.05]. Our results showed that rearing densities used in this study could not affect antioxidant defense development in early life stages of O. mykiss