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Relationship between number and levels of evidence of studies found based on search methodology.
| Levels of evidence | Number of studies |
% |
|---|---|---|
| Systematic review or meta-analysis | 1 | 2.70% |
| Review of the literature | 6 | 16.22% |
| Randomized clinical trial | 10 | 27.03% |
| Cohort study | 1 | 2.70% |
| Case-control study | 6 | 16.22% |
| Case series study | 8 | 21.62% |
| Case study | 4 | 10.81% |
| Research in animals | 0 | 0.00% |
| Opinion of specialist | 1 | 2.70% |
| 37 | 100% |
