Figure 2. Flow chart.

There were a total of 1315 records identified through the literature search, out of which 1113 were screened based on abstracts after removal of duplicates. The first level of screening based on abstracts resulted in exclusion of 1048 records (descriptive reviews, editorials, theories, books, book sections, non-human studies, and grey literature that didn’t fit our inclusion criteria), and the second level of screening based on full-text resulted in exclusion of 9 more additional records. Therefore, a total of 56 studies (1 randomized controlled clinical trial, 27 controlled clinical trials, and 28 observational/descriptive studies) were included in this review.