For the highest level of evidence (RCT) retrograde (root-end)-filling with glass ionomer cement is almost as effective as amalgam. However, there was a significant caveat as there were only two RCTs. At the next highest level of evidence (CCT), and given the additional caveat that there was only one controlled trial for each material, retrograde (root-end) EBA cement, composite with Gluma and gold leaf, as well as orthograde gutta-percha, may be more effective than retrograde (root-end) amalgam filling. In conclusion, these results suggest that additional validating CCTs and RCTs are needed.