| Study | State | Randomization | Allocation concealment | Blinding | Comparable baseline | >80% follow-up | Freedom of selective reporting | Level |
| Lee et al., 2006 [10] | Korea | Y, central controlled randomization | Y | Y, double blind | Y | Y | Y | A |
| Hurlstone et al., 2008 [11] | UK | Y, random sequence | Y | Y, double blind | Y | Y | Y | A |
| Katsinelos et al., 2008 [12] | Greece | Y, random number | Y | Y, double blind | Y | Y | Y | A |
| Yamamoto et al., 2008 [13] | Japan | Y, center controlled randomization | Unclear | Unclear | Y | Y | Y | B |
| Kizu et al., 2010 [14] | ā | M | Unclear | Unclear | Y | Y | Unclear | C |
| Moss et al., 2010 [15] | Australia | Y, random sequence | Y | Y, double blind | Y | Y | Y | A |
| Fasoulas et al., 2012 [16] | Greece | Y, block balance random sequence | Y | Y, double blind | Y | Y | Y | A |
| Kishihara et al., 2012 [17] | Japan | M | Y | Unclear | Y | Y | Y | B |
| Yoshida et al., 2012 [18] | Japan | M | Unclear | N | Y | Y | Y | C |
| Kim et al., 2013 [19] | Korea | Y, random sequence | Y | Y, double blind | Y | Y | Y | A |
| Sumiyama et al., 2014 [20] | Japan | Y, computer generated random sequence | Y | Y, double blind | Y | Y | Y | A |
|
|