[Endodontic surgery (apicoectomy)--success rate of more than 90% using dental operating microscope and ultrasonic tips].

The main cause of root canal treatment failure is presence of bacteria in the root canal. Surgical endodontic retreatment is indicated as a valuable treatment choice for failed endodontic treatment. The aim of the article is to describe the advantages of a new technique for apicoectomy using dental operating microscope and ultrasonic tips in comparison to the traditional technique. Precise root end resection with minimal or no bevel and accurate preparation of the root end cavity to the depth of 3-4 mm allows minimal bone removal and reduces procedural accidents such as perforation of the lingual canal wall. Zink oxide eugenol based materials allow sealing of the retrograde preparation adequately to prevent bacteria and toxins to penetrate the periradicular tissues. Literature review demonstrates success rate to above 90% when employing dental operating microscope and ultrasonic tips for retrograde cavity preparation.