Comparative evaluation of antimicrobial efficacy of silver diamine fluoride, chlorhexidine varnish with conventional fluoride varnish as a caries arresting agent. An in vivo sodium dodecyl sulfate-polyacrylamide gel electrophoresis study

Introduction: Silver diamine fluoride (SDF) is employed as an adjunct cariostatic agent in the management of dental caries in high-risk population. Other than fluorides, chlorhexidine (CHX) is the most potent antimicrobial and efficacious agent against Streptococcus mutans. Aim: The aim of this study is to evaluate and differentiate the efficacy of 38% silver diamine fluoride, CHX varnish, and fluoride varnish on carious primary teeth. Materials and Methods: Ninety children having a count of ?1 carious lesion were recruited. Thirty-eighty percent silver diamine fluoride or fluoride varnish and CHX varnish were topically applied on the lesion. The primary outcome measured was the arrest of carious lesion (lesion rendered inactive as per the Nyvad criteria) after a follow-up of 14–21 days. Dental biofilm sample was obtained from each child and subsequently assessed for microbial composition by colony-forming unit method before and after treatment followed by protein analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis method. Results: Average proportion of arrested caries lesions in the SDF group was higher followed by CHX and fluoride varnish groups. Decreased total protein amount was found in SDF group. This proves that there is decrease in microbial load posttreatment in SDF group. Conclusion: Thirty-eight percent SDF is more effective than CHX varnish and fluoride varnish in arresting dentin carious lesions in young children.

RNA interference for the control of whiteflies (Bemisia tabaci) by oral route.

RNA interference (RNAi)-mediated gene silencing was explored for the control of sap-sucking pest Bemisia tabaci, commonly known as whitefly. dsRNAs and siRNAs were synthesized from five different genes – actin ortholog, ADP/ ATP translocase, α-tubulin, ribosomal protein L9 (RPL9) and V-ATPase A subunit. A simplified insect bioassay method was developed for the delivery of ds/siRNA through the oral route, and efficacy was evaluated. ds/siRNA caused 29–97% mortality after 6 days of feeding. Each insect ingested nearly 150 nl of insect diet per day, which contained a maximum of 6 ng of RNA. Knocking down the expression of RPL9 and V-ATPase A caused higher mortality with LC50 11.21 and 3.08 μg/ml, respectively, as compared to other genes. Semi-quantitative PCR of the treated insects showed significant decrease in the level of RPL9 and V-ATPase A transcripts. siRNAs were found stable in the insect diet for at least 7 days at the room temperature. Phloem-specific expression of dsRNAs of RPL9 and V-ATPase A in transgenic plants for the protection against whiteflies might be an interesting application of this technology.