Canal Configuration of the Mandibular Second Molar Using a Clinically Oriented In Vitro Method

By Weine FS, Pasiewiicz RA and Rice RT

Date: 06/1988
Journal: JOE

Summary: 

•Purpose:

To classify the most common canal configurations available in the mandibular 2nd molar

•N= 75 extracted mandibular 2nd molars

•Materials & Methods:

•Placed teeth in5.25 % NaOCL immediately after extraction and stored for several weeks.

•Preoperative radiographs were taken from straight and angle

•Access cavities and estimated WL then placing files in extracted teeth and radiographing from two directions

•Classification for configurations (Weine et al):
  Type I single canal from the pulp chamber to the apex

  Type II, two canals exiting from the chamber floor and merging into one main canal short of the apex

  Type III, two separate and distinct canals leaving the floor of the chamber and exiting as eparate and distinct canals at the apex.

Most highlighted Results: 

  • Only 3 teeth (4%) had one root, 1.3% had one canal and 2.7% were C-shaped
  • 72 teeth presented 2 roots üOut of the complete sample (75 teeth), 3 teeth (4.0%) with a type I canal, 39 teeth (52.0%) with a type II, and 30 teeth (40.0%) with a type III
  • In the distal root, 64 teeth (85.3%) had a type I canal , 7 teeth (9.3%)  type II , and one tooth (1.3%) was a type III
  • 8 teeth (10.7%) had four canals with type II or III canals in the distal root, and types II or III in the mesial root.

Clinical significance:

•Proper pre-operative evaluation, proper angled radiography, and prior anticipation of present canals number and configuration enhances the clinical outcome

•Establishing presence of C-shaped canals is important.