Study Random selection
in the population 		Definition of inclusion
and exclusion criteria 		Report of losses
to follow-up 		Validated
measurements 		Statistical
analysis 		Risk of
bias
Altiparmak et al. [18] No Yes No Yes Yes High
González-García et al. [21] No Yes No Yes No High
Garcez-Filho et al. [22] No Yes Yes Yes Yes Moderate
Santagata et al. [23] No Yes No Yes No High
Albanese et al. [24] No Yes No Yes Yes High

Each study was categorized as low, moderate or high risk of bias.