Study Year of
publication 		Random
sequence
generation		 Allocation
concealment		 Blinding of
participants
and personnel		 Blinding of
outcome
assessment 		Incomplete
outcome
data		 Selective
reporting 		Other
sources of
bias
Smiler et al. [4] 2008 ? ? + + + + +
Castillo-Cardiel et al. [5] 2016 ? + + + + + +
McNulty et al. [6] 2012 ? ? + ? + + +
Dhar et al. [7] 2012 ? ? + + + + +
Marycz et al. [8] 2016 + ? + + + + +
Lyahyai et al. [9] 2012 ? ? ? + + + ?
Kassis et al. [10] 2006 ? ? ? + + + ?
Li et al. [11] 2015 ? ? - ? + + +
Sato et al. [12] 2016 ? ? + ? + + +
Motlló et al. [33] 2014 ? ? - + + + +
Anguita-Compagnon et al. [34] 2010 ? ? + + - + +

+ = low risk; ? = unclear risk; - = high risk.