Treatment considerations of the middle mesial canal of mandibular first and second molars

By Pomeranz HH, EidelmanDL, and Goldberg M G

Date: 03/1981
Journal: JOE



To describe the occurrence, debridement, and obturation of middle mesial canals in lower 1st and 2nd molars as observed during clinical treatment. 

N= 100   1st (61) and 2nd (39) mandibular molars that were consecutively treated in a private endodontic practice 


-Types of middle mesial canals::

  • Fin, the instrument could pass freely between the MB or ML canal and the middle mesial canal.
  • Confluent when the prepared canal originated as a separate orifice but apically joined the MB or ML canal.
  • Independent when the prepared canal originated as a separate orifice and terminated as a separate foramen . a broad single mesial canal in which three master cones could be cemented to the apex

-After complete serial preparation of other canals, if a catch or possible orifice for MM canal was found, the canal was negotiated. 

Most highlighted Results:

1.A middle mesial canal was identified in 12%. 58.3% of these were treated in first molars.

2.More mesiolingual fins were encountered than mesiobuccal fins.

3.Two of the middle mesial canals were confluent. One joined the MB canal and the other joined the ML canal.

4.One independent canal (in 1st molar) originated in a separate orifice and terminated in a separate apical foramen.

5.The other independent canal (in 2nd molar) began as the middle portion of a single wide mesial canal and terminated in the middle portion of a wide apex.

Clinical significance:

It is most important to locate, debride and obturate the middle mesial canal during routine RCT of lower molars.