| Number of roots | Root canal anatomy | Diagnostic mode | Country | Reference |
| 1 root | 3 canals | R/G | USA | Nallapati [46], 2005 | 3 canals | R/G | India |
N. Kararia and V. Kararia [60], 2013 | 4 canals | R/G | Isreal | Holtzman [61], 1998 | 4 canals | R/G | USA | Wong [62], 1991 | 5 canals | R/G | Argentina | Macri and Zmener [63], 2000 | C-shaped | Micro-CT after extraction | Britain | Cleghorn et al. [55], 2008 |
| 2 roots | 2 canals | R/G | India | Goswami et al. [64], 1997 | 2 canals | R/G | India | Prakash et al. [65], 2008 | 3 canals | R/G | China | Chan et al. [53], 1992 | 3 canals | R/G | Germany | Rödig and Hülsmann [66], 2003 | 3 canals | R/G | Belgium | De Moor and Calberson. [67], 2005 | 3 canals | R/G | Iran | Lotfi et al. [68], 2008 | 3 canals | R/G | Brazil | Soares et al. [69], 2009 | 3 canals | R/G | Iran | Shokouhinejad [70], 2009 | 3 canals | R/G | India | Aguiar et al. [71], 2010 | 3 canals | R/G | India | Poorni et al. [49], 2010 | 4 canals | R/G | USA | Bram and Fleisher [72], 1991 | 4 canals | R/G | Saudi Arabia | Al-Fouzan [73], 2001 | 4 canals | R/G | United Kingdom | Rhodes [74], 2001 | 4 canals | R/G | Greece | Tzanetakis et al. [75], 2007 | 3 canals | Extraction | USA | Fischer and Evans [54], 1992 | 3 canals | R/G | Iran | Shalavi et al. [76], 2012 | 3 canals | CBCT | Iran | Mokhtari et al. [77], 2013 | 4 canals | Extraction | USA | Shapira and Delivanis [78], 1982 |
| 4 roots
| 4 canals | SCT | Indian | Sachdeva et al. [79], 2008 | 4 canals | R/G | Greece | Farmakis [80], 2008 |
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