“…The current focus has been concentrated on direct clinical manipulation of cell-free regenerative endodontic therapy and the evaluation of a variety of biomaterial scaffolds. Over the last decade, a plethora of randomized controlled trials on REPs have been performed on evaluation or comparison of the different biomaterial scaffolds, including blood clot, collagen, PRP, PRF, PPP, PP, hydrogels, chitosan, and PLGA [ 28 , 31 , 40 , 88 , 89 , 93 , 128 , 186 , [232] , [233] , [234] , [235] , [236] , [237] , [238] , [239] , [240] , [241] ] ( Table 2 ). However, there is no sufficient evidence of a high level that compares the clinical outcome regarding the application of these biomaterial scaffolds in REPs. A systematic review and meta-analysis study was conducted to quantitatively assess the effect of various biomaterial scaffolds on the clinical outcomes of regenerative endodontic procedures in necrotic immature permanent teeth [ 242 ].…”