Table 2.
NOS for assessing study quality.
| Study | Selection | Comparability | Exposure | Total score |
|---|---|---|---|---|
| Fard et al. [19] | 3 | 2 | 3 | 8 |
| Mastropasqua et al. [20] | 3 | 2 | 3 | 8 |
| Abri Aghdam et al. [23] | 3 | 0 | 3 | 6 |
| Aghsaei Fard et al. [24] | 3 | 2 | 3 | 8 |
| Al-Nashar and Hemeda [25] | 3 | 2 | 3 | 8 |
| Augstburger et al. [26] | 3 | 1 | 3 | 7 |
| Fard et al. [27] | 3 | 2 | 3 | 8 |
| Fard et al. [28] | 3 | 2 | 3 | 8 |
| Hata et al. [29] | 3 | 2 | 3 | 8 |
| Liu et al. [30] | 3 | 2 | 3 | 8 |
| Liu et al. [31] | 3 | 2 | 3 | 8 |
| Pierro et al. [32] | 2 | 2 | 3 | 7 |
| Sharma et al. [33] | 3 | 2 | 3 | 8 |
| Song et al. [34] | 3 | 2 | 3 | 8 |