Table 2.

Risk of bias summary in included studies

Bias risk	Tekgündüz et al., 2014 [16]	Shaeri et al., 2017 [19]	Mohamed & Ahmed, 2018 [15]	Ghasemi et al., 2019 [20]	Choi et al., 2015 [17]	Fazli et al., 2017 [18]	Karbandi et al., 2013 [13]	Fouda et al., 2018 [14]
Random sequence generation (selection bias)	?	Y	Y	Y	N	Y	Y	Y
Allocation concealment	?	?	?	?	?	?	?	?
Blinding of participant and personnel	?	N	?	?	?	N	?	?
Blinding of outcome assessment	?	N	?	?	?	N	?	?
Incomplete outcome data	Y	Y	Y	Y	Y	N	Y	Y
Selective reporting	Y	Y	?	?	?	Y	?	?

(?): Unclear risk of bias; Yes (Low risk); N: No (High risk)