The exhaustive revision of the universal literature shows us that the nowadays use of Glass Ionomer Cements (GICs) is controversial, because many researchers state that GICs are biocompatible with dental tissues, while others demonstrate its cytotoxicity, especially when they are modified with resin (RMGIC). The aim of this study is to emphasize the cytotoxicity of these materials and its limitations in the clinical use to the dentistry community. Each year many patients with dental necrosis caused by this material, are treated in our Endodontics Clinic. Clinicians must have the appropriate knowledge to use them properly. Based on this literature review, and in our previous histopathological findings it can be concluded that RMGICs  and metal reinforced GICs (CERMET) have higher cytotoxic effects on pulp tissue, that conventional GICs.