Study Selection Comparability Result Score
Mayta-Tovalino et al. [22] ** * ** *****
Dvorak et al. [30] * * ** ****
Shabestari et al. [31] *** * ** ******
Seki et al. [32] ** * ** *****
Renvert et al. [33] ** * ** *****
Bell and Bell [34] *** * * *****
Astolfi et al. [35] ** * * ****
Suvarna et al. [36] *** * * *****
Apaza-Bedoya et al. [37] ** * ** *****
Romandini et al. [38] ** * ** *****

Studies that met five or more of the NOS scoring criteria were considered to be of good quality.