Table 3.

Study quality of the included studies based on the modified Jadad scale

	Author, year	Randomization	Concealment of allocation	Double blinding	Total withdrawals and dropouts	Total	Quality
1	Sarvilinna et al. [19]	**	*	*	**	06	Good
2	Sarvilinna et al. [20]	*	*	*	*	04	Good
3	Sarvilinna et al. [21]	*	*	*	*	04	Good
4	Berend et al. [22]	**	*	*	**	06	Good
5	Cook et al. [23]	**	*	*	*	05	Good
6	Meek et al. [24]	**	*	*	**	06	Good
7	Zhang et al. [25]	*	*	*	*	04	Good
8	Savin et al. [26]	*	*	*	*	04	Good
9	Singh et al. [27]	**	*	*	**	06	Good
10	Singh et al. [28]	**	*	*	**	06	Good
11	Katz et al. [29]	**	*	*	**	06	Good
12	Thien et al. [30]	**	*	*	**	06	Good
13	Ricioli Jr et al. [31]	*	*	*	*	04	Good
14	Gromov et al. [32]	*	*	*	*	04	Good
15	Lindberg-Larsen et al. [33]	**	*	*	**	06	Good
16	Tamaki et al. [34]	*	*	*	*	04	Good

*Indicates one point

**Indicated two points