SummaryThe aim of thisin vitrostudy was to test the ability of a novel non‐instrumental technique to prepare and obturate root canals. Cleaning of the root canal system was achieved with a device which was able to develop, under reduced pressure, controlled cavitation. The same device was used for proper drying and subsequent obturation of the root canal system. A total of 55 freshly extracted molars with 120 canals were treated either by the step‐back technique and lateral condensation of gutta‐percha and AH26 as a sealer or by the new device. The teeth were then sectioned horizontal to the long axis of the root canal and examined by light microscopy. The cross‐sectional area, area with residual pulpal tissue and voids were assessed morphometrically. Overall, the treatment with the new device resulted in similar cleanliness and obturation quality when compared with the control group. Total treatment time using the new non‐instrumental technique, however, was less than half of that using hand instru