Regenerative endodontic procedures hold the promise of restoring the pulp/dentin complex in teeth damaged by infection, trauma or developmental anomaly of immature permanent teeth with necrotic pulp. REPs have the potential advantages over traditional treatment procedures of increasing root wall thickness and root length while maintaining immune competency and nociception. Teeth with large apices involve increased revascularization rates, mainly because of increased possible ingrowth of newly formed blood vessels.