简介：Thepurposeofthisstudywastoevaluatethelongtimeantibacterialpropertiesandshearbondstrengthofexperimentalnanosilver-containingcements(NSC).Nanosilverbaseinorganicantibacterialpowderwasaddedtothereinforcedglassionomercementatfivedifferentweightratiostoobtainaseriesofnanosilver-containingcements,thentheantibacterialpropertiesofthreeorthodonticcementproductsandfiveNSCsampleswereevaluatedbythedirectcontacttest(DCT)andtheagardiffusiontest(ADT).TheDCT,whichwasbasedonturbidnessdeterminationofbacterialgrowthin96-wellmicrotiterplates,wasperformedinbothfreshandagedfor1day,1week,2weeks,3weeks,4weeks,6weeks,and8weekstestedmaterials.TheshearbondstrengthesofthreeorthodonticcementproductsandfiveNSCsampleswereexaminedusingauniversaltestingmachine.TheADTresultsindicatedthattherewerenosignificantdifferencesbetweenNSCsandORTHOLCfreshspecimens.IntheDCTexperiment,allfreshsilvernanoparticles-containingtestedsamplespresentedpowerfulantibacterialproperties,buttheygraduallylosttheeffectiveantimicrobialagentswiththeextensionofagingtime.Finally,noneofthetestedmaterialsmaintaineditsantibacterialpropertyafteragingfor8weeks.Agraduallydecreasingtrendofbondstrengthpresentedwiththeincreasingincorporationofnanosilverbaseinorganicantibacterialpowderintotheglassionomercement,eventhoughallthetestedmaterialspecimensreachedtheidealbondstrengthrange.WemayconcludethatNSCscancontributetodecreasethedemineralizationratearoundbracketswithoutcompromisingbondstrength.