Potential of Treated Dentin Matrix Xenograft for Dentin-Pulp Tissue Engineering.

INTRODUCTION: This study aims to develop and characterize the regenerative potential of an atelopeptidized treated dentin matrix xenograft using in vitro and in vivo models. METHODS: Freshly extracted bovine dentin was pulverized into 250- to 500-µm particles and demineralized with 17% EDTA for 1, 7, and 13 days. The samples were atelopeptidized with pepsin. The degree of demineralization and the effect of atelopeptidization were assessed using field emission scanning electron microscopy combined with energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy, respectively. The expression of dentin matrix acidic phosphoprotein 1, dentin sialophosphoprotein, and osteopontin was evaluated in dental pulp stem cells using quantitative real-time polymerase chain reaction. The samples were then implanted intramuscularly in rats for 30 days, and the inflammatory cells were quantified histologically. RESULTS: Field emission scanning electron microscopy combined with energy-dispersive X-ray spectroscopy revealed an exposed tubular structure of dentin after 1 and 7 days of demineralization. Fourier transform infrared spectroscopy confirmed the absence of amide peaks at 1260 to 1640/cm after atelopeptidization. The dental pulp stem cell expression of dentin matrix acidic phosphoprotein 1 and dentin sialophosphoprotein increased in all compared with the untreated control group (P < .05). The maximum expression rates were observed for the 1-day demineralized and atelopeptidized group. The 1-day demineralized group elicited the highest inflammatory response compared with the 7- or 13-day demineralized groups (P < .001). Atelopeptidization significantly decreased the inflammatory response only in the 1-day demineralized dentin group (P < .05). CONCLUSIONS: Atelopeptidization of 1-day demineralized dentin xenograft preserved the collagen structure, minimized the immune reaction, and provided sufficient regenerative potential.

The role of stem cell therapy in regeneration of dentine-pulp complex: a systematic review.

Infection of the dental pulp will result in inflammation and eventually tissue necrosis which is treated conventionally by pulpectomy and root canal treatment. Advances in regenerative medicine and tissue engineering along with the introduction of new sources of stem cells have led to the possibility of pulp tissue regeneration. This systematic review analyzes animal studies published since 2010 to determine the ability of stem cell therapy to regenerate the dentine-pulp complex (DPC) and the success of clinical protocols. In vitro and human clinical studies are excluded and only the experimental studies on animal models were included. Dental pulp stem cells constitute the most commonly used cell type. The majority of stem cells are incorporated into various types of scaffold and implanted into root canals. Some of the studies combine growth factors with stem cells in an attempt to improve the outcome. Studies of ectopic transplantation using small animal models are simple and non-systematic evaluation techniques. Stem cell concentrations have not been so far reported; therefore, the translational value of such animal studies remains questionable. Though all types of stem cells appear capable of regenerating a dentine-pulp complex, still several factors have been considered in selecting the cell type. Co-administrative factors are essential for inducing the systemic migration of stem cells, and their vascularization and differentiation into odontoblast-like cells. Scaffolds provide a biodegradable structure able to control the release of growth factors. To identify problems and reduce costs, novel strategies should be initially tested in subcutaneous or renal capsule implantation followed by root canal models to confirm results.