The purpose of this study was to investigate the capability of 3rd year dental students without endodontic experience to start with ProFile .04 Taper (DeTrey Maillefer, CH). To standardize the experimental design 102 industrial plastic blocks (Maillefer) were filmed before treatment. In total twenty-six subjects participated in the study: 12 dental students (DS) of the third year without any endodontic experience and 12 practitioners (P) with dental skill of one to ten years did 3 plastic blocks each. Furthermore a skilled endodontist (E) and a previously trained student (TS) operated another 15 each. For canal preparation up to #35 the manufacturers guidelines were followed, the canal was lubricated with glycerine and rinsed with water after each size. At the end every block was filmed again and the pictures were superimposed. The canal aberration was measured in 9 levels beginning at the apex. In total 16 instruments fractured: 1x#20, 2x#25, 10x#30 and 3x#35 thus being a rate of 9,41% (16 out of 170 instruments). Mean time for root canal treatment steadily decreased from the first block to the third in each group (DS: from 17,1 to 11,5 and 8,6 minutes; P: 10,2 - 6,5 - 6,3; E: 5,4 - 5,3 - 5,0; TS: 6,2 - 6,1 - 5,3) with dental students showing the highest speed up. All preparations exhibited a good taper, smooth walls and a definite apical stop. The most intensive work on the outer aspect of the canal was carried out near the apex (levels 1-3) for all groups with an aberration of 0,11 to 0,24 mm (DS), 0,18 to 0,19 mm (P) or 0,20 to 0,16 mm (E and TS). Regarding the inner aspect the removal increased steadily in all groups from level 1 to 6 and decreased slightly up to level 9. These findings show that even students lacking any endodontic experience can easily learn to use ProFile .04 with success and achieve a good root canal geometry. Schlagwörter: NiTi, dental education, plastic block, ProFile, canal aberration