The preparation of coronal isthmus is a fundamental step for long term success

To illustrate the use of ultrasonic tips and operating microscope in the preparation of coronal isthmus in premolars with two root canals and the mesial isthmus of first molars. Materials and methods: For preparation of the coronal isthmus ultrasonic tips were used, under the operating microscope. Results: The results demonstrates, preparation of the isthmus, to be a effective and useful step in removal of the pulp tissue which otherwise would have remained in this delicate area, leading to a probable failure of endodontic treatment. Discussion and conclusions: The positive results shown by these case studies illustrates, how essential and efficient are the operating microscope combined with the ultrasonic tips in executing a proper cavity access and retrieval of all the canal orifices. © 2012 Società Italiana di Endodonzia.