The name comes from the letter "C" shape appearance of a very large isthmus in the pulp chamber floor when viewed from above. This isthmus or groove is the result of the merging of some or all of the root canals at the cervical area near the pulp chamber floor. Incidence is 2,7% in Caucasian and up to 13% in asian population. Pre operative X Ray dental film shows a blurred image of the canal system, canals are not visible and pulp chamber is almost not visible. Looking at these features it may not be possible to diagnose a C shape canal but we must suspect either this canal configuration or severe fibrosis/calcification.

"C" shape canals are a real challenge to preparation and may cause technical complications such as transportation, steps, stripping with perforation in the thin wall area or blockage of the canal.

This procedure requires a full understanding of this anatomy to prepare an optimal access cavity to pulp chamber through a PFM abutment,  to know where to look for the root canal entries and to be cautious about the thin wall area. This endodontic procedure also requires much more operating chair time for debridment. No rapid techniques does exist to shape clean and fill those peculiar root canal shapes. This specific endodontic procedure also justifies the use of a dental operative microscope to better see what we are doing. 

Case number 319947

This 3D video of a "C" shaped second mandibular molar from the rootcanalanatomyprojectblogspot.com displays the complex anatomy of such a root canal system. In just a few second the video gives a better understanding on how difficult the cleaning and filling tasks of a "C" shape root canal may be.  

Last september, a new generation of endodontic file has been presented at the CAE meeting in Quebec city-Canada by Dr Zvi Metzger, Professor and Chair Department of Endodontology school of Dental Medicine at Tel Aviv University. Although at the moment, the Self Adjusting File System (SAF System) is not yet readily available everywhere in Canada, this innovative endodontic file adapts to root canal shape thus, may represent in a near future, a valuable approach to more efficient debridement in C shape canals and a safer way to address thin wall section that is always present in this anatomical variation. Here is a promotional video showing how it works. 

This is a symptomatic mandibular first premolar (bridge abutment) with a "C" shape root canal system. Most C-shaped canals occurs in mandibular second molars but they have been also reported in the mandibular first molar, the maxillary  first and second molars and the mandibular first premolar. This "C" shape first mandibular premolar root canal system is extremely rare. The only orthograde way to endodontically treat this anomalous root is to bring our first K file #06 to the apical third by bypassing what looks like a "mega concretion". Use of the dental operative microscope, sonic and ultrasonic instrumentation is mandatory. Being familiar with access cavity preparation for "C" shape RC through prosthetics, being familiar with cleaning, shaping and an obturation of a mineralized "S" shape root canal is also important. A cone beam tomography would have been most helpful in determining which root canal configuration we were dealing with prior to initiating this RCT and this very same tomo would have helped us in orienting our search for the pathway to the apex, but patient was reluctant to this innovative technology and decided to go for it only if symptoms persisted. Only one single pathway to the apex was found, tooth is now completely asymptomatic. Since we could not confirm this with a tomo, lets hope we were dealing with only one apex. (a type III Vertucci root canal configuration). A close follow up is planed.  

Esforzandose para hallar los caminos hacia el apice contorneando un "mega pulpolito" en  un sistema de canales radiculares anormales.

Este es un primer molar mandibular sintomatico (diente pilar) con un sistema radicular (nervio)  en forma de "C". Muchos canales radiculares en forma de "C" ocurren en los segundos molares pero ellos han sido reportados en el primer molar mandibular(inferior), el primer y segundo molar maxilar(superior), y el primer premolar mandibular(inferior). Esta forma de "C" en el canal radicular del primer premolar mandibular(inferior) es extremadamente raro. La unica forma(orthograde) para tratar endodonticamente de esta anomalia radicular es trayendo nuestro K file #06 hacia el tercio apical contorneando lo que parece un mega pulpolito (piedra). El uso del microscopio dental, instrumentacion sonica y ultrasonica es obligatoria. Estar familiarizado con el acceso a la preparacion cavitaria en forma de "C" a traves una corona, estar familiarizado con la limpieza, dar una forma al canal y hacer la obturacion de un canal radicular mineralizado en forma de "S" es tambien importante. Una tomografia (CBCT) podria haber sido de mucha ayuda determinando cual canal radicular nosotros debemos tratar antes de comenzar, y esta misma tomografia podria habernos ayudado en la orientacion de nuestra busqueda de los caminos hacia el apice, pero el paciente rehusa esta tecnologia innovadora y decide ir solo si los sintomas persisten despues del tratamiento. Solo fue hayado un camino simple hacia el apice, el diente es ahora completamente asintomatico. Desde que nosotros no podamos confirmar esto con una tomo, esperando que nosotros tratamos solo un apice. (un canal radicular de tipo III de Vertucci), un seguimiento cercano del caso es planeado.

Case study number: 331737

Heated gutta percha was most useful to obtain that so sought after 3D obturation in this mandibular second molar.

En esta radiografia podemos observar la dificultad para tener un acceso adecuado al canal radicular en su tercio distal en forma ¨S¨ ; La gutapercha caliente fue mas util para obtener el resultado que se deseaba, los canales radiculares han sidos sellados tanto hacia apical como hacia sus extensiones laterales, como una obturacion 3D.

Case study: 402 

Dental operative microscope was most usefull in order to assess level of cleanliness of this very challenging canal configuration

Case study 340:

Pulpitis on a mandibular second molar with a huge bone loss to distal, a rather bad prognosis. Patient wanted to keep her "Hopeless" tooth for as long as possible. Root canal treatment prolonged the tooth lifespan for another 2 years.