Thisstudy wasaimedtoevaluatetheeffectofmovementkinematicsandpreflaringonapical debrisextrusionafterinstrumentationwiththe WaveOnefile.Materials andMethods:A total of28single-rootedteethwithcurvature lessthan10˚were selected.Theteethwere assigned into4groups(n=7);G1:(150˚-30˚withSX), G2:(150˚-30˚)G3:(90˚–45˚withSX)&G4: (90˚–45˚).WaveOneprimaryfile(#258%)wasusedtoprepareallthecanalsin3parts;coronal middleand apical. Whilethepreflaringwasdoneusing Protaper SXfileinG1andG3tohalf oftheestimatedworkinglength.Thedebris collectionwasdoneusingMyersandMontgomery methodwithEppendorftubes.After drying,themeanweightof debris wasassessedwitha microbalance. Results:Mann-WhitneyUtestwas usedtostudytheeffectofpre-flaringandthe effectofreciprocationrangeondebrisweightP-value≤0.05.Theresultsshowedthattherewas no statisticallysignificant differencebetween 2reciprocation ranges ontheamountofapically extrudeddebris.Also, there wasnostatistically significantdifference betweenthepreflaring and the non-preflaring groups. Conclusion:withintheparametersofthisstudy,thesmallreciprocationrangescan be used withoutfear. Moreover,  thepreflaringpriorto reciprocation files is not amandatorystep.