Table 2.

The quality assessment of RCTs

Studies	Randomization	Concealment of allocation	Double blinding	Withdrawal and dropout	Total score
Baker 2007 [13]	1	2	2	1	6
Carlsson 2005 [14]	2	2	1	1	6
Fernandez-Fairen 2013 [15]	2	2	2	1	7
Fricka 2015 [16]	2	2	1	1	6
Fricka 2019 [17]	2	2	1	1	6
Gao 2009 [18]	2	2	1	1	6
Khaw 2002 [19]	1	2	2	1	6
Kim 2014 [2]	2	2	2	1	7
McCaskie 1998 [20]	1	2	1	1	5
Nam 2019 [21]	2	2	2	1	7
Park 2011 [22]	2	2	2	1	7