Table 3 Percentages of root canal configurations found in maxillary first premolars in the present and previous studies

Vertucci and Gegauff [12]

1979

North America

400

Clearing

8

18

–

62

7

–

–

5

Kartal et al. [30]

1998

Turkey

300

Clearing

8.7

1

–

71.3

14.7

2.3

0.3

1.3

Chaparro et al. [32]

1999

Andalusia

150

Radiograph

1.3

37.3

–

58

–

–

–

3.3

Sert and Bayirli [34]

2004

Turkey

221

OP & CDR

10.5

12.5

5.5

61.5

3.5

1

–

3

Lipski et al. [35]

2005

Poland

142

Radiograph

2.1

6.3

–

82.4

–

–

–

9.2

Peiris [43]

2008

Sri Lanka

153

Clearing

1.3

16.3

2

64

5.9

5.9

0.7

–

Japan

81

4.9

29.6

2.5

45.7

2.5

8.6

–

–

Atieh et al. [8]

2008

Saudia

246

Radiograph

8.9

26.8

–

63

–

–

–

1.2

Awawdeh et al. [27]

2008

Jordan

600

Clearing

3.3

10.2

0.3

79.7

2

2.3

–

1.5

Rwenyonyi et al. [36]

2011

Ugandan

202

M-clearing

13.0

29.6

1.9

71.6

1.9

1.9

3.7

3.4

Tian et al. [44]

2012

Chinese

241

CBCT

23

51

1

Gupta et al. [19]

2015

North India

250

Clearing

23.2

14.8

13.6

33.2

6.8

2

4

0.4

Senan et al. [42]

2018

Yemen

250

Clearing

13.2

4.4

8.0

55.6

5.6

1.6

3.6

0.8

ALqedairi et al. [31]

2018

Saudi

707

CBCT

10.8

8.4

1.8

70.6

3.9

2.1

0.3

2.1

Liu et al. [41]

2019

Chinese Adolescent

324

Micro-CT

25

8.33

2.78

52.78

5.56

2.78

1.54

1.23

Maghfuri et al. [29]

2019

Saudi

100

CBCT

0

7

0

75

13

2

0

3

Wu et al. [40]

2020

Shandong Chinese

1268

CBCT

10.4

24.2

0.39

58.6

4.9

0.87

0

0.39

Asheghi et al. [47]

2020

Iran

462

CBCT

8.87

15.15

0.86

71.64

1.30

0.22

0

1.95

Kfir et al. [20]

2020

Israel

400

CBCT

2

17

0.5

74

0.5

6

–

–

Al‑Zubaidi et al. [28]

2021

Saudia Arabia

500

CBCT

5.2

32.8

0.6

57.8

2.0

–

–

1.6

Present study

2021

Sulaimani

142

DR

0.70

0.70

–

70.43

26.05

–

–

2.12