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ePaper created 2018-05-16, 11:45:19 | version 1.38.0
SURGICAL AND NONSURGICAL ENDODONTIC RETREATMENTS —From theory to practice canals, there are lateral canals, anasto- moses, apical ramifications and other ar- eas that need to be cleaned during the endodontic treatment. Those areas can- not be accessed with the means of instru- mentation and disinfection that we have available today.2 Isthmuses and apical deltas and ramifications are among these areas. The term “root canal system” is used to describe this complex anatomy (Figs. 1a & b).2 More recent findings using 3-D microcomputed tomography imaging have proved the inability to shape and disinfect the entire root canal surface area.3 Coronal microleakage and micro- organisms that are resistant to antimicro- bial medicaments and disinfection tech- niques, such as Enterococcus faecalis, can also maintain the intraradicular infec- tion.4–6 The importance of an adequate permanent restoration for the long-term success of an endodontic treatment has been proved in many studies.7–9 In addition, the presence of a true cyst, formation of a microbial biofilm, and micro organisms such as Actinomyces and Propionibacterium propionicum that cause periradicular infections resistant to endo dontic treatment procedures are among the factors that can cause an ex- tracanal pathology.10, 11 Even if a paper point is accidentally extruded into the periradicular tissue when treating partic- ularly a necrotic case, it can cause an acute inflammatory response and ex- tracanal infection. Histological images of a true cyst show that it is an entity com- pletely enclosed in stratified squamous epithelium, without any apparent commu- nication with the root canal.12 Therefore, it is less likely to heal by a nonsurgical endodontic treatment or retreatment. In the case of a true cyst, apical surgery is the treatment of choice. uncertainty regarding its therapeutic result. This view was based on past expe- rience with accompanying inappropriate surgical instruments, inadequate visual- ization, frequent postoperative complica- tions and failures that often resulted in extraction of the tooth. However, in the early 1990s, new theories and equipment were developed in the field of surgery.13 The operating microscope, ultrasonic tips for root end preparation, surgical micro- instruments and new, more biocompatible materials for root end filling led to better understanding of the apical anatomy, greater success rates and improved responses from patients.13 Therefore, end- odontic surgery evolved into microsur- gery. Endodontic microsurgery is an apical surgical procedure that combines the magnification and illumination provided by the operating microscope with the proper use of new microinstruments.14 The operating microscope, ultrasonic tips, microsurgical instruments and the latest root end filling materials constitute the “triad of endodontic microsurgery” that was introduced after 1992. The use of the operating microscope in endodontic surgery allows for inspection of the apical surface at high magnifica- tion, thus revealing anatomical details such as isthmuses, canal fins and lateral canals that may cause endodontic treat- ment failure. Moreover, at higher magni- fication, an osteotomy can be made smaller, and by use of digital radiographs and video capture options offered by the micro scope, communication with the referring dentist or specialist is signifi- cantly improved.13, 15 Surgical versus nonsurgical retreatment—Treatment decisions Endodontic microsurgery Endodontic surgery was traditionally con- sidered to be the last treatment option, as it was viewed with negativity and The aim of the microsurgical technique is a minimally invasive procedure.13 This means a small osteotomy, about 3–4 mm in size, just enough to allow for an ultrason- ic tip of 3 mm to prepare the root end — Dr. Spyros Floratos, Greece Introduction A case of failure of a previous endodontic treatment is a clinical situation that we face in the office very often and the treat- ment plan, as well as the communication with the patient, is a challenging task. Failure of an endodontic treatment may involve extrusion of filling materials into the periradicular tissue, iatrogenic errors that either block the root canals or alter their natural anatomy. Alternatively, a ra- diographically satisfactory endodontic treatment may fail and, combined with the presence of intraradicular posts and permanent restorations, access for retreat ment may not be feasible or prac- tical. This article describes the decision- making criteria for providing nonsurgical retreatment or apical surgery as the treat- ment of choice for the management of endodontic treatment failure. Failure of endodontic treatment Reasons for failure of an endodontic treatment that are reported in literature essentially involve the presence of intra- radicular infection, while others have to do with factors that cause an extraradic- ular infection. This means microorganisms found outside the root canals.1 The com- plexity of the root canal anatomy is one of the causes of failure of an endodontic treatment.2 Anatomical studies published as early as 1925 described this complexity and showed that, apart from the main root 44 — issue 2018 Endodontics Article