Present status and future directions: Minimally invasive root canal preparation and periradicular surgery

Inspired by several other surgical disciplines, the quest for treating diseases through minimally invasive procedures has permeated endodontics, but not without controversy. Indeed, pulp amputation/excision and root-end resection are akin to surgical procedures elsewhere in the body and therefore, an increasing number of studies have addressed the "potential" to adopt such minimally invasive procedures in root canal treatment, with the larger goal of conserving tooth tissue for long-term survival of treated teeth. Yet, it is undeniable that this "trend" has been met with immense resistance with unclear evidence to strongly support or refute this philosophy. One may view root canal treatment as having two important procedural parts: (i) gaining access to the root canal and (ii) achieving clean root canals to remove the necrotic/infected or irreversibly inflamed tissues and then fill the space that was occupied by the pulp tissue and subsequently enlarged during cleaning and shaping, which should result in two key long-term outcomes: (i) healing of periradicular periodontitis and (ii) survival/retention of the tooth. Whilst a lot of interest has been directed towards gaining access through minimally invasive cavity designs, it is surprising that little effort has been expended on studying minimally invasive root canal preparation or surgical intervention. The aim of this review is not to promote or denigrate these philosophies, but to provide a balanced overview of the concepts, currently available evidence and future perspectives on minimally invasive endodontics from the context of root canal preparation and surgical endodontics. Specific attention is given to the role of modern irrigation strategies in potentially improving canal cleanliness even when canals are minimally prepared and the areas of research that are currently lacking in this topic.