Endodontic access cavity (AC) preparation represents a crucial—and oftentimes underappreciated—phase in successful root canal treatment.
Traditionally, access cavities have been designed according to the principles of “convenience form” and “extension for prevention,” prioritizing effective access and visualization of the root canal system at the expense of structural integrity.
However, over time, awareness has grown that removing excessive tooth structure—particularly from the pulp chamber roof and marginal ridges—can weaken the tooth and increase susceptibility to fracture.
In response, a paradigm shift toward minimally invasive endodontics has emerged.
This movement aligns with broader trends in restorative dentistry that emphasize maximal preservation of sound dental tissue
Enabled by advancements in magnification, illumination, CBCT imaging, ultrasonics, and nickel–titanium instrumentation, clinicians are now able to craft more conservative cavity designs without sacrificing precision.
Building on this, Silva et al. proposed a clear, four-type classification for AC designs: traditional (TradAC), conservative (ConsAC), ultraconservative (UltraAC), and truss access cavities (TrussAC), helping bring consistency to crowded terminology.
► DENTAL BOOK: Cohen’s Pathways of the Pulp – 12th Edition (2020): The Ultimate Guide in Endodontics
In their comprehensive systematic review and meta-analysis, Ballester and colleagues synthesized data from 33 studies examining these four access strategies—evaluating outcomes ranging from fracture resistance and canal detection to shaping efficacy, apical debris extrusion, and procedural errors.
Notably, they found that ConsAC and TrussAC designs offer significantly higher fracture resistance compared to traditional cavities, but only when both marginal ridges remain intact.
In contrast, no such mechanical advantage was observed when one or both ridges were compromised.
Additionally, the authors highlighted an important trade-off: the risk of missed canals increases with conservative designs when not assisted by advanced visualization techniques like dental operating microscopes and ultrasonic troughing.
► READ ALSO: The Evolution of Vital Pulp Therapy: Advances in Diagnosis, Materials, and Clinical Success (2018–2025)
The authors ultimately advocate for a balanced, case-specific approach—preserving tooth structure as much as practical, yet never at the expense of treatment efficacy.
TrussAC remains unsupported by current evidence, while UltraAC may find limited application in niche scenarios.
To guide clinicians, the team also proposes a structured decision-making protocol aimed at tailoring access cavity design to each clinical situation.
The full PDF delves deeper into the methodology, subgroup analyses, and practical algorithms to optimize access cavity design in modern practice. I highly recommend reading it in full:
