The C-shaped root canal configuration: a review

By Jafarzadeh H, Wu YN.

Date: 01/2007
Journal: JOE

Summary:

  • Etiology: Failure of the Hertwig’s epithelial root sheath to fuse on the lingual or buccal root surface is the main cause of C-shaped roots. The C-shaped root may also be formed by coalescence because of deposition of the cementum with time
  • Fan’s Classification (Radiographic):
  • 1. Type I: conical or square root with a vague, radiolucent longitudinal line separating the root into distal and mesial parts. There was a mesial and a distal canal that merged into one before exiting at the apical foramen.
  • 2. Type II: conical or square root with a vague, radiolucent longitudinal line separating the root into distal and mesial parts. There was a mesial and a distal canal, and the two canals appeared to continue on their own pathway to the apex.
  • 3. Type III: conical or square root with a vague, radiolucent longitudinal line separating the root into distal and mesial parts. There was a mesial and a distal canal, one canal curved to and superimposed on this radiolucent line when running toward the apex, and the other canal appeared to continue on its own pathway to the apex
  • Epidemiology:
  • Mand. 1st molar – 18% of Chinese population (Lu et al 2006)
  • Mand. 2nd molar – 31.5% of Chinese (Yang et al 1988), 11% of Saudi Arabian (Al-Fouzan 2002)
  • 3rd molars – 11% in Thai (Gulabivala 2002)
  • Overall, seldom occurrence in Caucasians or maxillary 1st molars.
  • Diagnosis:
  • Radiographic – 20 degree mesial/distal angle to see.
  • Clinical – The pulp chamber in teeth with C-shaped canals may be large in the occlusoapical dimension with a low bifurcation.
  • Management:
  • Access cavity for teeth with a C-shaped root canal system varies considerably and depends on the pulp morphology of the specific tooth
  • In all categories, the mesiobuccal and distal canal spaces usually can be prepared normally. However, the isthmus should not be prepared with larger than no. 25 files; otherwise, strip perforation is likely.
  • Also, Gates-Glidden burs should not be used to prepare the mesiobuccal and buccal isthmus areas. Extravagant use of small files and 5.25% NaOCl is a key to thorough debridement of narrow canal isthmuses. Also conservative us of ultrasonics.
  • Thermoplasticized gutta percha for obturation. Lateral condensation not ideal.