Root Anatomy and Root Canal Configuration of Human Permanent Mandibular Premolars: A Systematic Review

Table 2

Summary of the incidences of documented ethnic and population variations in the anatomy of mandibular second premolars.

Geographic; and ethnic; distribution	Materials; and; methods	No. of teeth in the study (𝑛)	Root anatomy			Root canal anatomy				Root canal pattern (Vertucci)									Apical foramina			References
			1; root	2 roots	>2 roots	1 canal	2 canals	>2 canals	C-shaped	Type I	Type II	Type III	Type IV	Type V	Type VI	Type VII	Type VIII	Others types	1	2	3
Caucasian
France	In vitro: radiograph and sectioning	328	97.6% (320)	2.4% (8)	0%; (0)	86.6% (284)	13.4% (44)															Geider et al. [4], 1989
Germany	In vitro: analysis of extracted teeth	2089	99.85% (2086)	0.05% (1)	0.1% (2)																	Visser [41], 1948
Poland	In vitro: extraction and RCT	56				68.2% (38)	31.8% (18)	0%; (0)	0%; (0)													Rózyło et al. [6], 2008
U.S.A	In vitro: clearing	400	100% (400)	0%; (0)	0%; (0)	97.5% (390)	2.5% (10)	0%; (0)	0%; (0)	97.5% (390)	0%; (0)	0%; (0)	0%; (0)	2.5% (10)	0%; (0)	0%; (0)	0%; (0)	0%; (0)	97.5% (390)	2.5% (10)	0%; (0)	Vertucci [7], 1984
	In vitro: sectioning	32	100% (32)	0%; (0)	0%; (0)	65.6% (21)	34.4% (11)															Barrett [11], 1925
	In vitro: extraction and radiograph	906	96.6% (902)	0%; (0)	3.4% (4)	87.5% (792)	12.5; (112)	0.4% (2)	0%; (0)													Zillich and Dowson [12], 1973
	In vitro: grinding and examination under magnification	50				92% (46)	8%; (4)	0%; (0)	0%; (0)										96% (48)	4% (2)	0%; (0)	Green [9], 1973
Subgroup ethnic incidence		3861	98.81%	0.49%	0.7%	82.9%	17.1%	0.07%	0%	97.5%				2.5%					96.75%	3.25%
African
Senegalese	In vivo: radiographic examination	408				86% (351)	12% (49)	2%; (8)	0%; (0)													Mbaye et al. [15], 2008
Indian
India	In vitro: clearing	40				80% (32)	20%; (8)	0%; (0)	0%; (0)	80% (32)	0%; (0)	0%; (0)	2.5% (1)	17.5% (7)	0%; (0)	0%; (0)	0%; (0)	0%; (0)	80% (32)	20% (8)	0%; (0)	Parekh et al. [19], 2011
	In vitro: SCT	96	97.9% (94)	2.1% (2)	0%; (0)	87% (83)	13.5% (13)	0%; (0)	0%; (0)	80% (78)	9%; (9)	3%; (3)	2%; (2)	4%; (4)	0%; (0)	0%; (0)	0%; (0)	0%; (0)	94% (90)	6%; (6)	0%; (0)	V. K. Sikri and P. Sikri [21], 1994
Subgroup ethnic incidence		136	97.9%	2.1%	0%	83.5%	16.75%	0%	0%	80%	4.5%	1.5%	2.25%	10.75%					87%	13%
Mongoloid
China	In vivo: CBCT	178	100% (178)	0%; (0)	0%; (0)	97.2% (173)	2.2%; (4)	0%; (0)	0.6%; (1)	97.2% (173)	0%; (0)	0%; (0)	0.5% (1)	1.69% (3)	0%; (0)	0%; (0)	0%; (0)	0.5%; (1)				Tian et al. [25], 2012
Japan	In vitro: radiograph	40				97.9% (39)	2.1%; (1)	0%; (0)	0%; (0)													Miyoshi et al. [29], 1977
Korea	CBCT	789	99.4% (784)	0.6% (5)	0%; (0)																	Park et al. [31], 2013
Subgroup ethnic incidence		1007	99.7%	0.3%	0%	97.5%	2.15%	0%	0.3%	97.2%			0.5%	1.69%				0.5%
Middle east
Kuwait	In vitro: radiograph of RCT teeth	64	95.6% (61)	4.4% (3)	0%; (0)	95.3% (61)	4.7%; (3)	0%; (0)	0%; (0)										95.3% (61)	4.7% (3)	0%; (0)	Zaatar et al. [32], 1997
Jordan	In vitro: clearing	400	97.2% (389)	2.8% (11)	0%; (0)	72% (288)	27.5% (110)	0.5% (2)	0%; (0)	78% (288)	3.8% (15)	0.1% (4)	7.5% (30)	15.3% (61)	0%; (0)	0%; (0)	0%; (0)	0.5%; (2)	74.2% (337)	15.8% (63)	0%; (0)	Awawdeh and Al-Qudah [33], 2008
Iran	In vitro: clearing	103	100% (103)	0%; (0)	0%; (0)	80.5% (83)	17.5% (18)	0%; (0)	2%; (2)	76.3% (76)	7.9% (9)	9.9% (11)	5.9% (7)	0%; (0)	0%; (0)	0%; (0)	0%; (0)	0%; (0)	94.1% (97)	5.9% (6)	0%; (0)	Rahimi et al. [35], 2007
	In vitro: clearing and sectioning	80				88.8% (71)	11.2% (9)	0%; (0)	0%; (0)	91.2% (73)	0%; (0)	0%; (0)	0%; (0)	0%; (0)	0%; (0)	0%; (0)	0%; (0)	0%; (0)	97.5% (78)	2.5% (2)	0%; (0)	Hasheminia and Hashemi [39], 2005
	In vitro: clearing	137				94.2% (129)	5.8%; (8)	0%; (0)	0%; (0)										75.9% (104)	24.1% (33)	0%; (0)	Rahimi et al. [40], 2009
Turkey	In vitro: clearing	100	100% (100)	0%; (0)	0%; (0)	93.6% (94)	6.4%; (6)	0%; (0)	0%; (0)	93.6% (94)	0%; (0)	0%; (0)	0%; (0)	6.4% (6)	0%; (0)	0%; (0)	0%; (0)	0%; (0)	93.6% (94)	6.4% (6)	0%; (0)	Çalişkan et al. [36], 1995
	In vitro: clearing	200	100% (200)	0%; (0)	0%; (0)	71% (142)	29% (58)	0%; (0)	0%; (0)	71% (142)	7% (14)	3.5% (7)	9% (18)	7%; (14)	1.5% (3)	1%; (2)	0%; (0)	0%; (0)	81.5% (163)	18.5% (37)	0%; (0)	Sert and Bayirli [37], 2004
Subgroup ethnic incidence		1084	98.56%	1.44%	0%	85.06%	14.59%	0.07%	0.29%	82.02%	3.74%	2.7%	4.48%	5.74%	0.3%	0.2%		0.1%	87.44%	11.13%
Hispanic
Mexico	In vitro: radiographs	250				98.8% (247)	1.2%; (3)	0%; (0)	0%; (0)										98.8% (247)	1.2% (3)	0%; (0)	Pineda and Kuttler [38], 1972
Total no of teeth		6746	5649	34	6	3364	489	12	3	1346	46	46	58	105	3	2	0	3	1741	179	0
Overall incidence			99.28%	0.61	0.01%	86.9%	12.64%	0.31%	0.08%	83.65%	2.86%	2.86%	3.6%	6.52%	0.18%	0.12%	0%	0.18%	90.68%	9.32%	0%