From evolution to revolution (while remaining a clinician)

The anatomy of the root canal system has always been fascinating to researchers, academicians, and clinicians. From the early works of Walter Hess in 1925 to the most advanced micro-CT imaging techniques in 2020, one can appreciate the extensive isthmuses, anastomoses, lateral canals, and fins of root canals, making them a challenging environment to exert microbial control — the ultimate goal of any clinician.

Thankfully, the discipline of endodontics has witnessed multiple evolutionary advancements in terms of instrumentation, irrigation, and obturation, with the hope of overcoming challenges associated with the anatomy. Clinicians can think of the various NiTi file designs and various motions yielding a multitude of rotary systems over the last decade or the advances in irrigation fluid dynamics and agitation, as well as the various sealers and obturation techniques that have become available to us.

However, there is an emerging current revolution in endodontics taking place within these evolutionary advancements aimed at setting a new philosophy, one that is more biologically based than just technically based. For instance, root canal instrumentation is shifting from “rotary instrumentation” — a scenario where the file shapes the canal, leaving behind a considerable amount of untouched areas, to “adaptive instrumentation,” a scenario where the file expands and adapts itself to the irregular ovoid shapes of canals, hence respecting root canal anatomy and yielding a cleaner canal. This allows for a more conservative approach and less dentin removal, contributing to long-term strength of the tooth. These new adaptive files, such as the XP-3D Shaper™ (Brasseler USA^®), can be used during both primary root canal treatments and retreatments. Their expandable potential helps in grabbing and pulling out the root canal filling materials, especially stubborn gutta-percha tags attached to axial walls, in a fast, clean, and secure manner.

Irrigation is also experiencing its share of revolution in terms of delivery and activation systems. From passive ultrasonic irrigation, XP-3D Finisher™ (Brasseler USA), EndoVac™ (Kerr Dental), and GentleWave^® (Sonendo) to nanocatalysts, it is clear that it is getting easier and more predictable to chemically disinfect inaccessible areas of the root canal system.

Without a doubt, root canal obturation is the aspect of endodontic therapy that has undergone the most important changes over the years — probably because of the insatiable desire to obtain a particular radiographic “look.” Sadly, most of the “evolutionary’’ obturation techniques still rely on gutta percha to overcome the poor performance of traditional sealers in terms of dimensional stability and proper bonding to the dentinal surfaces, not to mention their lack of biocompatibility and mitotic activity. Today the development of bioceramic-based sealers, such as EndoSequence^® BC Sealer™ (Brasseler USA) or BioRoot™ RCS (Septodont), offers a safe and predictable way to obtain a long-term seal of the root canal system without excessive preparation in the coronal component of the root canal space to accommodate obturation procedures. It was these paradigm changes in obturation that sparked the chain reaction to revolutionize all other steps of endodontic therapy.

Finally, in this fast-paced world we live in, we should not sink into the mindset of mastering techniques. Rather, we should always question the biology behind it, hence challenging the clinician within each one of us.

Dr. Chafic Safi