Table 3.

Cochrane Collaboration’s tool risk of bias assessment.

References	Randomization Process	Deviations from Intended Interventions	Missing Outcome Data	Measurement of the Outcome	Selection of the Reported Result	Overall Bias
Nistor [8]	+	+	+	+	+	+
Reichert [21]	+	+	+	+	+	+
Dienstknecht [22]	+	+	+	Not stated	+	+
Cheng [23]	+	+	+	-	+	+
Taunton [24]	+	+	+	-	+	+
Barret [25]	+	+	+	-	+	+
Zhao [26]	+	+	+	+	+	+
Taunton [27]	+	+	+	-	+	+
Brun [28]	+	+	+	+	+	+

“+” denotes low risk of bias, “-” denotes high risk of bias.