Apical Limits in Root Canal Therapy: A Review of Techniques and Success Rates

Abstract

The evolution in root canal therapy over the past few decades has been toward improving treatment outcomes and long-term success. One of the most important factors influencing the success of RCT is the accurate establishment of the apical limit or working length, where cleaning, shaping, and filling should precisely terminate within the root canal. This limit is very important since both over- and under-instrumentation could equally lead to postoperative discomfort, complications, and potential treatment failure. This paper reviews the different methods of determination of the apical limit, including radiographic techniques, electronic apex locators (EALs), tactile sensation, and cone-beam computed tomography (CBCT). The advantages and limitations of each technique are diverse: radiography is widespread but prone to distortion; EALs are highly accurate but environmentally sensitive.
Many studies have proven that accurate apical limit management is strongly related to the successful result of RCT. Combined EAL with radiographic methods demonstrated very high success rates in managing difficult canal anatomies. This review is to stress the importance of precise apical limit determination in reducing complications and enhancing the long-term results of RCT, while also presenting the potential of emerging technologies in further sharpening endodontic accuracy.
The root canal therapy forms the basis of endodontic treatment inorder that teeth that could otherwise be lost because of infection or necrosis may be saved. Success in RCT depends upon effective debridement, disinfection, and sealing of the root canal system with special care given to the apical limit or the endpoint of instrumentation and obturation. This article reviews the concept of apical limits, explores the different techniques used to establish these limits, and discusses their influence on success rates in root canal therapy.