Mandibular First Molar with Four Distal Canals

Root Anatomy and Canal Configuration of the Permanent Mandibular First Molar: A Systematic Review

“…The presence of a third root was higher among Asians, Mongolians, and Eskimos. The incidence of 4 roots was very rare and was only reported in 3 case reports (61)(62)(63).…”

The Morphologic Characteristics of the Distolingual Roots of Mandibular First Molars in a Taiwanese Population

“…More molars (70.1%) were extracted than premolar (62.6%) and anterior teeth (23.4%); this is, in part, because of more complex canal anatomy of molars than premolars and anterior teeth. A case report of mandibular first molars with four distal canals revealed the complexity of distal root canal system (20). Therefore, a thorough inspection of the pretreatment radiograph and interpretation of certain characteristics, such as double PDL images of distal roots or an unclear view of the distal root/canal, could assist in identifying the presence of DL roots.…”

Mandibular First Molar with Six Separate Canals

“…As many as 4 canals have been reported in the mesial or the distal root, but rarely do these canals remain separate, and rarely are there higher numbers of canals in both roots. The incidence of a third canal in the distal root of the mandibular first molar can vary from 0.2%-3%, depending on the population studied (10,11), and with multiple canals, there might be an additional root (3). Early work on tooth anatomy showed 3 separate canals in the mesial root of mandibular first molars very rarely (12,13).…”

“…Early work on tooth anatomy showed 3 separate canals in the mesial root of mandibular first molars very rarely (12,13). Multiple canals have also been demonstrated in the distal root of the mandibular first molar (3,4). The presence of distinct multiple canals, while making treatment more complex, is still much easier to treat than C-shaped canals, which are extremely difficult to clean and shape properly with thin dentin walls (14).…”

“…Canal systems commonly seen within these roots are 2 canals in the mesial root and 1 or 2 canals in the distal root. Previous case reports have shown as many as 4 canals in the mesial root and up to 4 canals in the distal root but often no more than 6-7 canals within the mandibular first molar (2)(3)(4)(5)(6)(7)(8). Very often these canals join nearby canals, so on obturation there appear to be fewer canals present.…”