Clinical Atlas of Retreatment in Endodontics. Группа авторов

Introduction to endodontic retreatment

       Sanjay Miglani, Fugen Dagli Comert, Swadheena Patro, and Viresh Chopra

      There has been massive growth in endodontic treatment in recent years. The main aim of root canal treatment is to disinfect and shape the root canal system and seal it in three dimensions to prevent reinfection of the tooth [1, 2]. Although initial root canal therapy is known to be a predictable procedure with a high degree of success [3–6], failures can occur after treatment.

      Literature has reported failure rates of 14–16% for initial root canal treatment [3, 7]. Lack of healing is due to persistent intraradicular infection residing in previously uninstrumented canals, dentinal tubules or in the complex irregularities of the root canal system [8–11]. The extraradicular causes of endodontic failures include periapical actinomycosis [12], a foreign body reaction due to extruded endodontic materials [13, 14], an accumulation of endogenous cholesterol crystals in the apical tissues [15] and an unresolved cystic lesion [16, 17].

      The term ‘retreatment’ is widely used in endodontics to denote a new intervention aimed at retaining the tooth in the oral cavity [18]. Previously treated teeth with persistent periapical lesion(s) might be preserved with non‐surgical retreatment or endodontic surgery, assuming the tooth is restorable and periodontally sound, and the patient wants to retain the tooth. When a decision is made to preserve the tooth, the clinician and patient face the challenge of selecting the treatment with the most beneficial long‐term outcome.

      Evidence‐based dentistry recommends selection of alternative treatment options based on the best available evidence [19]. Intuitively, a considered medical procedure is regarded as meaningful only if it is thought to bring about some benefit to the patient. Accordingly, the consequences of treating or not treating the disease in question must be at the core of the clinical decision‐making process.

I.1 Definition

      According to the Glossary of Endodontic Terms of the American Association of Endodontists, retreatment [20] is defined as:

       A procedure to remove root canal filling materials from the tooth, followed by cleaning, shaping and obturation of the root canals.

      The indications for ‘root canal retreatment’ given by the European Society of Endodontology [21] are:

The above definitions, though correct, describe only one clinical situation of reintervention – when there is need to remove the previous root canal filling material.

      Carr [22] proposed an updated and comprehensive definition of reintervention:

       Endodontic retreatment is a procedure performed on a tooth that underwent a previous attempt at definitive treatment resulting in a condition that requires further endodontic intervention to achieve a successful outcome.

I.2 Rationale for retreatment

      Root canal system anatomy plays a significant role in endodontic success and failure [23–25]. It contains branches that communicate with the periodontal attachment apparatus furcally and laterally, and often terminate apically into multiple portals of exit [26]. Therefore, any opening from the root canal system (RCS) to the periodontal ligament space should be thought of as a portal of exit (POE) through which potential endodontic breakdown products may pass [27, 28].

      There can be various causes for endodontic failures such as:

      Regardless of all the causative factors, the final cause for failure is leakage and bacterial contamination due to inadequate debridement, disinfection or sealing of the RCS.

      Success can be achieved in previously failed endodontic cases by confirming the restorability of the tooth in question, careful treatment planning and proper execution of the treatment plan. In addition, it depends upon the skill of the individual operator performing the procedure.

I.3 Aim of endodontic retreatment

      The aim of retreatment is to perform an endodontic treatment that can render the treated tooth functional and comfortable again, allowing complete repair of the supporting structures. Before starting the retreatment, it is profoundly important to consider all interdisciplinary treatment options in terms of time, cost, prognosis and potential for patient satisfaction.

      It is important to evaluate the endodontic failures so a decision can be made among non‐surgical retreatment, surgical retreatment or extraction [33, 34, 35].

      Retreatment is classified into two major groups [18].

      Clinicians should always opt for non‐surgical retreatment over the surgical option unless a successful outcome cannot be achieved by a non‐surgical approach.

With the advent of magnification and newer retreatment technologies, non‐surgical retreatment procedures take care of mechanical failures, previously missed canals or radicular subcrestal fractures. Non‐surgical endodontic retreatment procedures have enormous potential for success if the guidelines for case selection are respected and the most relevant technologies, best materials and precise techniques are utilized [21–23].

      This book focuses on a variety of failed endodontic cases that have been treated successfully with different non‐surgical as well as surgical approaches. The aim of this book is to discuss: