Pullal Response to the Combined Use of Mineral Trioxide Aggregate and Iloprost for Direct Pulp Capping  
[PERSON]  
1 Department of Restorative Dental Sciences, College of Dentistry, King Saud University,  
Riyadh 11612, Saudi Arabia; [EMAIL_ADDRESS] (A.A.); [EMAIL_ADDRESS] (F.A.)  
[PERSON]  
2 Department of Oral Medicine and Diagnostic Sciences, College of Dentistry, King Saud University,  
Riyadh 11545, Saudi Arabia; [EMAIL_ADDRESS] 2  
[PERSON]  
3 Department of Pharmaceutical, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia; [EMAIL_ADDRESS] 3  
[PERSON]  
1 Department of Restorative Dental Sciences, College of Dentistry, King Saud University,  
Riyadh 11612, Saudi Arabia; [EMAIL_ADDRESS] (A.A.); [EMAIL_ADDRESS] (F.A.)  
[PERSON]  
4 Department of Restorative Dental Sciences, College of Dentistry, Jazan University, Jazan 45142, Saudi Arabia; [EMAIL_ADDRESS] 4  
[PERSON]  
1 Department of Restorative Dental Sciences, College of Dentistry, King Saud University,  
Riyadh 11612, Saudi Arabia; [EMAIL_ADDRESS] (A.A.); [EMAIL_ADDRESS] (F.A.)  
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More recently, iloprost has been introduced as a potential agent for direct pulp capping [7]. Iloprost upregulates the mRNA expression of vascular endothelial growth factor (VEGF), fibroblast growth factor-2, and platelet-derived growth factor in human dental pulp stem cells [4]. In addition, it enhances tertiary dentin formation and pulpal blood flow in a mechanical exposure model in a rat molar [4; 7]. Furthermore, the angiogenic potential of iloprost was confirmed in a more recent study when a tooth slice organ culture system was used for evaluation [8]. However, the requirement of a delivery system was noted.  
Mineral trioxide aggregate (MTA) is a calcium silicate-based material that is associated with high success rates when used as a pulp capping material [9; 10; 11]. Although MTA is biocompatible, has good sealing ability, and is capable of stimulating tertiary dentin formation [12], several attempts have been made to improve its biological properties by mixing it with various additives. The addition of growth hormone [13], osteostatin [14], platelet-rich fibrin [15], or human placental extract [16] has been shown to enhance the proliferation and differentiation in human dental pulp stem cells compared to MTA alone. Recently, it has been found that mixing MTA with iloprost enhances the differentiation potential of mesenchymal stem cells compared with MTA mixed with distilled water ([PERSON] et al., 2021, unpublished data). Thus, we suggest that iloprost could be mixed with MTA in the clinic to improve the outcome of direct pulp capping procedures. Based on previous in vitro findings, the current study was conducted to assess the combined effects of MTA and iloprost when used as a pulp capping material on pulpal inflammation and tertiary dentin formation compared with MTA and iloprost alone in an in vivo experiment in rat molar teeth.