ABSTRACT
INTRODUCTION: Dental pulp is a complex tissue with highly differentiated cells, which makes its reconstruction a challenging task. The apical papilla is an undifferentiated tissue considered as the remnant of the dental papilla that forms the dentin-pulp complex. Aiming to analyze morphologic features of the tissue formed in an in vivo pulp model, we used human apical papilla as a cell source without the use of exogenous growth factors. METHODS: A construct was built using newborn mice molar crowns treated with TrypLE (Fisher Scientific, Loughborough, UK) and EDTA. The crowns were filled with PuraMatrix (Corning Inc, Corning, NY) and a pool population of human apical papilla cells. As a control, we used crowns filled only with PuraMatrix and empty crowns. The constructs were transplanted under severe combined immunodeficient mice kidney capsules. Immunohistochemistry for lamin A, dentin sialophosphoprotein, and dentin matrix protein 1 was performed. RESULTS: Morphologic analysis of all transplanted crowns showed the formation of a loose connective tissue of variable cellularity with the presence of well-formed functional vessels. In the study group, lamin A-positive cells represented the majority of cells within the pulp chamber and a few cells in the vessel lining. We also found positivity for dentin sialophosphoprotein and dentin matrix protein 1, an indicator of odontoblast differentiation. CONCLUSIONS: In our study model, human transplanted apical papilla cells mixed with the host cells and formed a vascularized viable tissue, and these cells were able to differentiate into odontoblastlike cells without the use of exogenous growth factors.
