Table 4.

Risk of bias assessment

Study	Randomization of specimens	Prior Sample size calculation	Similar size specimens	Manufactures’ instruction followed	Intervention defined	Control groups defined	statistical analysis considered	Blinding of observer	Loss of any specimen reported	All possible outcome reported	Overall risk of bias assessment
Redlich et al. (2008)[13]	No	No	Unclear	NI	Yes	Yes	Yes	NI	No	Yes	Moderate
Samorodnitzky et al. (2009)[14]	No	No	Unclear	NI	Yes	Yes	No	NI	No	No	High
Muguruma et al. (2011)[15]	No	No	Yes	NI	Yes	Yes	Yes	NI	No	Yes	Moderate
Krishnan et al. (2012)[16]	No	No	Yes	NI	Yes	Yes	Yes	NI	No	Yes	Moderate
Kang et al. (2015)[17]	No	No	Yes	NI	Yes	Unclear	Yes	NI	No	Yes	Moderate
Zhang et al. (2016)[18]	No	No	Yes	NI	Yes	Yes	Yes	NI	No	Yes	Moderate
Behroozian et al. (2016)[19]	No	No	Yes	NI	Yes	Yes	Yes	NI	No	Yes	Moderate
Shah et al. (2018)[20]	No	Yes	Yes	NI	Yes	Yes	Yes	NI	No	Yes	Low
Gracco et al. (2019)[21]	No	No	Yes	NI	Yes	Yes	Yes	NI	No	Yes	Moderate

No- not taken into consideration/insufficient information; Yes- sufficient information provided regarding the specified domain; NI- no information provided regarding the specific domain