Huang George T-J, Al-Habib Mey, Gauthier Philippe
Endod Topics. 2013 Mar 1;28(1):51-60. doi: 10.1111/etp.12035.
There are two types of approaches to regenerate tissues: cell-based and cell-free. The former approach is to introduce exogenous cells into the host to regenerate tissues, and the latter is to use materials other than cells in an attempt to regenerate tissues. There has been a significant advancement in stem cell-based pulp and dentin regeneration research in the past few years. Studies in small and large animals have demonstrated that pulp/dentin-like tissues can be regenerated partially or completely in the root canal space with apical openings of 0.7-3.0 mm using dental pulp stem cells, including stem cells from apical papilla (SCAP) and subpopulations of pulp stem cells. Bone marrow mesenchymal stem cells (BMMSCs) and adipose tissue-derived MSCs (ADMSCs) have also been shown to regenerate pulp-like tissue. In contrast, the cell-free approach has not produced convincing evidence on pulp regeneration. However, one crucial concept has not been considered nor defined in the field of pulp/dentin regeneration and that is the critical size defect of dentin and pulp. Without such consideration and definition, it is difficult to predict or anticipate the extent of cell-free pulp regeneration that would occur. By reasoning, cell-free therapy is unlikely to regenerate an organ/tissue after total loss. Similarly, after a total loss of pulp, it is unlikely to regenerate without using exogenously introduced cells. A cell homing approach may provide a limited amount of tissue regeneration. Although stem cell-based pulp/dentin regeneration has shown great promise, clinical trials are difficult to launch at present. This article will address several issues that challenge and hinder the clinical applications of pulp/dentin regeneration which need to be overcome before stem cell-based pulp/dentin regeneration can occur in the clinic.
基于细胞的方法和无细胞的方法。前一种方法是将外源性细胞引入宿主以再生组织，后一种方法是使用细胞以外的材料来尝试再生组织。在过去几年中，基于干细胞的牙髓和牙本质再生研究取得了重大进展。对大小动物的研究表明，使用牙髓干细胞，包括根尖乳头干细胞（SCAP）和牙髓干细胞亚群，在根尖开口为0.7 - 3.0毫米的根管空间中可以部分或完全再生牙髓/牙本质样组织。骨髓间充质干细胞（BMMSCs）和脂肪组织来源的间充质干细胞（ADMSCs）也已被证明可再生牙髓样组织。相比之下，无细胞方法在牙髓再生方面尚未产生令人信服的证据。然而，在牙髓/牙本质再生领域，一个关键概念尚未得到考虑和定义，即牙本质和牙髓的临界尺寸缺损。没有这种考虑和定义，就很难预测或预期无细胞牙髓再生可能发生的程度。通过推理，无细胞疗法在器官/组织完全丧失后不太可能使其再生。同样，牙髓完全丧失后，如果不使用外源性引入的细胞，也不太可能再生。细胞归巢方法可能只能实现有限的组织再生。尽管基于干细胞的牙髓/牙本质再生已显示出巨大潜力，但目前很难开展临床试验。本文将探讨几个挑战和阻碍牙髓/牙本质再生临床应用的问题，在基于干细胞的牙髓/牙本质再生能够临床应用之前，这些问题需要得到克服。
