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

Author/Year	Samples obtained through a standardized process	Single operator of the machine	Sample size calculation	Blinding of the testing machine operator	Specimens, tests, and formulas according to standard specifications	Total scores	Risk of bias
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