RESUMEN
Introduction: During instrumentation smear layer formationoccurs on dentinal wall and for a successful root canal itsremoval is necessary. Aim of the study was to compare effectof 17% EDTA, MTAD & 18%Etidronic acid (HEBP) + 5%NaOCl, irrigating solutions on smear layer removal andpenetrability of AH Plus sealer into dentinal tubules usingscanning electron microscopy (SEM).Material and methods: Sixty single rooted mandibularpremolars, were divided into three groups (n=20).Group -I17% EDTA, Group -II MTAD, Group -III 18%Etidronic acid+5% NaOCl. The final rinse was done by 5ml of solution for2 minutes. Ten samples from each group were evaluated atmiddle and apical thirds for smear layer removal using SEM.Remaining ten samples of each group were obturated withgutta-percha & AH PLUS sealer and evaluated at 5mm abovefrom the root apex for sealer penetration using SEM.Results: At middle 3rd no difference in smear layer removalwas seen between Group –I and Group -II For apical 3rdGroup- II showed better smear layer removal than Group–I and Group- III. Thus both in middle and apical thirdsMTAD showed better smear layer removal. For mean sealerpenetration Group -II showed a highest depth of sealerpenetration i.e, 231.37±18.12µm followed by Group -I154.95±22.53µm and Group –III 125.99±17.39µmConclusion: MTAD is effective in smear layer removal fromboth middle and apical thirds. Maximum depth of sealerpenetration was seen in MTAD group followed by EDTAgroup and least in Etidronic acid group