RESUMO
Aim: To evaluate the influence of residual calcium hydroxide (CH) intracanal medication consideringtwo dye leakage locations (apical foramen and middle root canal third) by quantifying the diffusionof India ink in length and depth. Methods: After biomechanical preparation, 72 single-rootedbovine teeth were divided into two groups in which half was filled with a CH and saline paste. After7 days, the medication was removed and the canals in both groups were filled. Half of thesamples had the apical third and part of middle third removed for infiltration of India ink at themiddle third (MTI), while the rest were infiltrated at the apical foramen (AI). The followingexperimental groups were formed (n = 18 each): A1 CH-medicated + AI, A2 CH-medicated+ MTI, B1 non-medicated + AI, B2 non-medicated + MTI. For evaluation of dye leakage, theexperimental specimens were cross-sectioned, photographed and had the infiltration perimetermeasured using the Image Tool 3.00 software. The Mann-Whitney U-test was used for statisticalanalysis (p<0.05). Results: The lowest values of dye penetration in length and depth werefound in the groups receiving intracanal medication (A1 and A2). Conclusions: Lower dyepenetration in length and depth at the two different locations was observed in the canals withresidual CH intracanal medication.