Table 1.

Cochrane Collaboration tool for quality assessment in the included studies.

Trials	Sequence generation	Allocation concealment	Blinding of outcome assessors	Incomplete outcome data	Selective outcome reporting	Others
Herkowitz et al	Low	High	Low	Low	Low	Low
Bridwell et al	Low	Unclear	Low	Low	Low	Low
Aihara et al	High	Unclear	Low	Low	Unclear	Low
Kleinstuect et al	Unclear	Unclear	Low	Low	Unclear	Unclear
Ghogawa et al	Low	Unclear	Low	Low	Low	Low
Forsth et al	Low	Unclear	Low	Low	Low	Low