Root Canal Mandibular Molar – Studies on Anatomy
Root Canal Madibular Molar Anatomy
micro-CBCT Study
My analysis of Wolf JOE 2016 for mesial root
- 55% are fairly straight forward like 2-2-1/1 or 1-2-2/2
- 7% are doable with a little luck like 2-1-1/2 or 1-1-1/2
- 38% are nearly impossible to completely access all canals like 2-1-1/3 or 2-2-2/4
Distal root is much better
- 73% are fairly straight forward like 2-2-1/1 or 1-1-2/2
- 12% are doable with a little luck like 2-1-1/2 or 1-1-1/2
- 15% are nearly impossible to completely access all canals like 1-1-1/3 or 1-1-2/3
de Pablo JOE 2010 Systemic review 41 studies
- Third root = 13% but strongly correlated with the ethnicity ie great variance
- Three canals 61%, 4 canals 36%, and 5 canals in 1%
- Mesial root = 2 canals 94%, 3 canals 2.3% The most common canal system configuration was Vertucci type IV (52.3%), followed by type II (35%)
- Distal root revealed type I configuration 62.7%, type II (14.5%) and IV (12.4%)
- Isthmus communications = 55% on mesial and 20% on distal root. What is an isthmus and what is a canal? Depends on age likely. In the young it is a canal in the elderly an isthmus
Brazil study molars 74% 2R3C 12% 2R4C 11% 2R2C 3% 1R2C
- first molars 1.7% C shape
If single distal canal then about 60% have mesial canals that join Gen Dent Lamia 2016
Middle Mesial Canal
There is an entire post on the mid mesial canal.
Distal Root
Worldwide 37% of distal roots have a second canal. This varies greatly by region and ethnicity though, as 60% of Egyptians have a second distal canal and only 16% of Venezuelans do. Martins JOE 2022
76%-13%-8%-3% 1-2-3-4 canals in distal root of two rooted molars. 100 extracted Brazilian teeth micro-CT JOE 2015 Filpo-Perez Interestingly 13% had canal systems not in Vertucci classification and are IMHO very complex.

G through N are unclassified shapes (although ignoring some minor isthmus connections many would fall into Vertucci system)
Radix root
We have a page all about radix roots.
Lower molar root canal anatomy
First molar = Systemic Review with 41 studies and almost 19k molars. de Pablo 2010 JOE
- 3 roots 13% and is strongly correlated with ethnicity.
- 3 canals 61%, 4 canals 36%, and 5 canals 1%.
- Mesial root = 2 canals 94% and 3 canals 2%. Vertucci type IV (52%), type II (35%).
- Distal root = type I 63%, type II (14%) and IV (13%).
- Isthmus communications 55% on mesial root and 20% on distal root.
Silva 2013 JOE Brazil study molars 54%=2R3C 32%=2R2C 4%=1R1C 3.5%=1R2C 3.5%=3R4C=Radix 2%=1R3C 1%2R4C
- second molars 3.5% C shape
If single distal canal then about 60% have mesial canals that join Gen Dent Lamia 2016
C shaped canal of lower molars
14% worldwide but much higher in China at 44% von Zuben JOE 2017
- Type I merging = all canals merge into one apical formen
- Type II symmetric = meisal and distal symmetrical canals viewed from BL
- Type III asymmetric = meisal and distal canals asymmetrical viewed from BL
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