Root canal anatomy of mandibular second molars. Part I

By Mannlng SA

Date: 07/1992
Journal: JOE


Purpose: to investigate the canal system of mandibular 2nd molars and its relationship to the patient’s age, race, sex and side of the mouth. 

N= 149 mandibular 2nd molars. 


The pulp was removed, the canal space filled with black ink and the roots demineraiized and made transparent .

The canal system was defined as follows: type 1, type 2-1, type 2, type1—2  and type 3

Most highlighted Results: 

1.Lateral canals were positioned most frequently in the apical third (59.4%) followed by the furcation area (22.6 %).

2.Transverse anastomoses were found in 1/3 of roots and were most frequent in the middle and apical thirds.

3.Most frequent canal type in single root (type3), in mesial root (type 2-1) and in distal root (type 1). 

4.Canal shape was significantly related to age,  oval canals (under 35 years of age) and round canals (over 35 years)

5.Canal shape was significantly related to race, with more c-shaped canals observed in teeth from Asians

6.The presence of apical deltas was significantly related to the sex & side of the mouth, male > female, left> right.

7.Mandibular 2nd molars with single roots had a more complex root canal system than two- rooted teeth, more lateral canals and transverse anastomoses were observed, apical foramen was found at the apex less frequently.

Clinical significance:

Dentists should be careful when treating single rooted and mesial root of the two rooted mandibular 2nd molars.