Table 3.

Results of the quality analysis of the included studies.

Quality Criteria	Alonso-Fernández10	Goel27	Lin28	Mortari29	Ozsarac25	Pendharker30	Quadri31	Taguchi26
Sample randomization	Yes	No	No	No	No	No	No	No
Comparison between treatments	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Blinding of participants	Yes	No	No	No	No	No	No	No
Description of measurement	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Statistical analysis	Yes	Unclear	Yes	Yes	Yes	Yes	Yes	Yes
Defined inclusion/exclusion criteria	Yes	No	Yes	Yes	Unclear–exclusion only	Yes	Yes	No
Report of follow-up	Yes	Yes	Unclear	Yes	Yes	Yes	Yes	Unclear
Risk of bias*	Low	High	High	Unclear	High	Unclear	Unclear	High

*Risk of bias assessment: Yes (high) = 0–4, unclear = 5–6, No (low) = 7.