['To assess the effectiveness of an active application of liquid etching, compared with the standard gel formulation on smear layer removal from post space walls and push-out bond strength of luted fibre posts.', 'Human extracted teeth were collected and root filled. After post space preparation and cleaning with 10% ethylenediaminetetraacetic acid for 30\xa0s, teeth were assigned to four groups (n\xa0=\xa011) according to etching procedure: (i) 37% phosphoric acid (H3 PO4 ) gel; (ii) 37% H3 PO4 liquid applied with an endodontic needle; (iii) 37% H3 PO4 liquid applied with an Endovac; (iv) no etching procedure (control group). Three teeth per group were sectioned longitudinally and prepared for SEM examination to evaluate the presence of smear layer, debris, sealer/gutta-percha remnants, and the number of open tubules. Eight teeth per group were bonded with an etch-and-rinse adhesive, and fibre posts were luted with a resin-based cement. After cutting, specimens were prepared for a push-out test. Data were analysed by anova and post hoc tests (P\xa0<\xa00.05).', 'Improved smear layer removal was obtained in Group 2, followed by Group 1, Group 3, and the control group (P\xa0<\xa00.05). The mean values for the bond strength of the push-out test were: Group 1, 8.3\xa0±\xa02.9\xa0MPa (coronal); 7.7\xa0±\xa03.0 (middle); 3.3\xa0±1.9\xa0MPa (apical); Group 2, 7.8\xa0±\xa02.1\xa0MPa (coronal); 6.9\xa0±\xa03.9\xa0MPa (middle); 3.7\xa0±\xa01.3\xa0MPa (apical); Group 3, 9.7\xa0±\xa02.8\xa0MPa (coronal); 8.6\xa0±\xa02.1\xa0MPa (middle); 6.9\xa0±\xa02.3\xa0MPa (apical); and Group 4, 2.9\xa0±\xa03.0\xa0MPa (coronal); 2.6\xa0±\xa02.0\xa0MPa (middle); 1.1\xa0±\xa02.0\xa0MPa (apical).'] Does active application of liquid etching agent improve adhesion of fibre posts to intraradicular dentine?