C-Shaped Canals Are Challenging

Claudia Hoffman, D.D.S.
C-Shaped Canals Are Challenging

Claudia Hoffman

EETH WITH C-shaped canals can be challenging and deceiving to dentists. C- shaped canals are usually found in mandibular second molars, and they represent 8 percent of second mandibular molars in the general population (Weine, 1998). There is an increased incidence in the Asian population, with 31.5 percent of second mandibular molars having C-shaped canals.
   The C-shaped root configuration is represented by fusion of mesial and distal roots. There are three categories of C-shaped canals (Melton et al, 1991). Type I is a continuous C-shaped canal. Type II is a semicolon-shaped canal, with dentin separating one distinct canal from a buccal or lingual C-shaped canal. Type III is two or more separate canals.
    There are many clinical considerations when treating teeth with C-shaped canals. There is a higher incidence of lateral canals, fins, and apical deltas. Therefore, debridement and shaping will be more challenging. The use of ultrasonics with irrigation will help with debris removal. C-shaped canals can change configuration or morphology at different levels along the length of the root. The dentin thickness between the external root surface and the internal root canal wall is less than in other teeth, so be careful not to strip the walls during shaping or post placement.
    C-shaped canals can present challenges to the dentist in debridement, obturation, and restoration. Root canal therapy on these teeth generally has a lower rate of success, and patients should be advised of this before treatment begins.

I	II	III

FIGURE 1: The three types of C-shaped canal.

July - September 2005

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