The crux of successful endodontics revolves around knowledge, respect, and appreciation for root canal anatomy and careful, thoughtful, meticulously performed cleaning and shaping procedures. Knowledge of pulpal anatomy, both the usual and unusual configurations and possible variations is critical for success in endodontics and lack of such knowledge may lead to treatment failure. One such variation of the root canal system is the C-shaped canal configuration. It is termed so because of the C-shaped cross-sectional anatomical configuration of the root and root canal.
What is a C-shaped canal?
C-shaped canal configuration is a variation that has a racial predilection and is commonly seen in mandibular second molars. The intricacies present in this variation of canal morphology can pose a challenge to the clinician during negotiation, debridement, and obturation.
What is the prevalence of the C-shaped canal?
In maxillary molars, C-shaped canal morphology is a rare ﬁnding, with the highest prevalence reported being 1.1% and 3.4% of ﬁrst and second molar teeth. Respectively. C-shaped canal conﬁguration in mandibular premolars was reported in only four papers. Although uncommon, results suggest that its prevalence might be greater in mandibular ﬁrst premolars. The prevalence of C-shaped canals in lower molars has shown greater discrepancies in different studies ranging from 0% to 44%, making such prediction unclear. However, lower second molars showed more C-shaped canals compared to lower first molars. Only a few studies compared the prevalence of C-shaped canals between men and women, and all came to the conclusion that there was an insignificant difference between both genders. Similarly, there is no significant difference between different regions and continents in the prevalence of C-shaped canals.
Anatomic classification of C-shaped canals
The high percentage of canal irregularities, such as accessory to lateral canals, and apical delta in a C-shaped canal makes it difficult to clean and seal the entire canal system adequately. The wide fins and small surface area of these canals preclude complete debridement using traditional hand instrumentation techniques, which can lead to failure of root canal therapy. Therefore, careful location and negotiation of the canals and the meticulous mechanical and chemical debridement of the pulp tissue should be carried out in order to successfully treat a C-shaped canal.
C-shaped canal morphology is an uncommon anatomical ﬁnding in maxillary molars, mandibular premolars, and mandibular ﬁrst molars. This meta-analysis revealed that gender and geographic region may act as a confounding factor for the prevalence of the C-shaped anatomy in mandibular second molars, whilst age did not inﬂuence the prevalence of C-shaped conﬁguration in this tooth group. The knowledge of these preoperative factors associated with a proper diagnostic tool would help clinicians to anticipate and treat this complex morphological variation of root canals in practice.