Table 3 Risk of bias assessment of the included studies. Clear description of the parameter = 0. Insufficient or unclear reported parameter = 1, no information of the parameter = 2. A total score between 0 and 3 = low risk of bias, a score of 4 to 7 = moderate-risk, scores of 8 to 10 = high-risk

Jamali Zavare, F. 2020 [23]

0

1

2

2

0

5

moderate

Mokhtari, H. 2018 [25]

0

1

1

2

2

6

moderate

Mokhtari, H. 2018 [24]

0

1

1

2

2

6

moderate

Kulan, P. 2018 [26]

0

1

2

1

2

6

moderate

Ahmed, H. 2018 [14]

0

1

2

1

2

6

moderate

Ahmad, A. 2017 [38]

1

1

2

1

2

7

moderate

Sobhnamayan, F. 2017 [39]

0

1

1

0

0

2

low

Marciano, M. A. 2016 [6]

0

1

2

1

0

4

moderate

Kulan, P. 2016 [29]

0

1

2

1

2

6

moderate

Ghasemi, N. 2016 [10]

0

1

1

0

0

2

low

Zapf, A. M. 2015 [30]

0

1

1

2

0

4

moderate

Prasad, A. 2015 [13]

0

1

1

2

1

5

moderate

Natu, V. P. 2015 [11]

0

1

2

1

1

5

moderate

Lee, B. N. 2014 [31]

1

1

2

1

1

6

moderate

Oloomi, K. 2013 [32]

0

1

1

1

0

3

low

Kang, J. Y 2013 [33]

0

1

2

2

2

7

moderate

Duarte, M. A. 2012 [8]

0

1

2

1

0

4

moderate

Lee, B. N. 2011 [3]

0

1

1

1

0

3

low

Jafarnia, B. 2009 [34]

0

1

1

2

1

5

moderate

Bortoluzzi, E. A. 2009 [9]

0

1

2

2

0

5

moderate

Huang, T. H. 2008 [15]

1

1

2

2

0

6

moderate

Ding, S. J. 2008 [35]

2

1

2

2

2

9

high

Wiltbank, K. B. 2007 [5]

1

1

2

1

0

5

moderate

Antunes Bortoluzzi, E. 2006 [36]

0

1

2

1

0

4

moderate