| Study | Reason for exclusion |
|---|---|
| Helou 2008 | The study is not an RCT. |
| Kagalwalla 2006 | The study is not an RCT. |
| Spergel 2002 | The study is not an RCT. |
| Spergel 2005 | The study is not an RCT. |
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