An in vitro Model of Human Dental Pulp Repair

Abstract

Abstract. Pulp tissue responds to dentin injury by laying down reactionary dentin secreted by existing odontoblasts or reparative dentin elaborated by odontoblast-like cells that differentiated from precursor cells in the absence of inner dental epithelium and basement membrane. Furthermore, growth factors or active dentin matrix components are fundamental signals involved in odontoblast differentiation. In vitro, dental pulp cells cultured under various conditions are able to express typical markers of differentiation, but no culture system can re-create pulp response to dentin drilling. This paper reports the behavior of thick slices from human teeth drilled immediately after extraction and cultured from 3 days to 1 month. Results show that the damaged pulp beneath the cavity is able to develop, in vitro, some typical aspects correlated to tissue healing, evidenced by cell proliferation (BrdU-positive cells), neovascularization (positive with antitype-IV collagen antibodies), and the presence of functional (3H proline-positive) cuboidal cells close to the injured area.After 30 days of culture, elongated spindle-shaped cells can be seen aligned along the edges of the relevant dentin walls, whereas sound functional odontoblasts are well-preserved beneath healthy areas. This tissue recovery leads us to believe that such a culture model will be a useful system for testing factors regulating pulp repair.

Voltage-gated Sodium Channels Confer Excitability to Human Odontoblasts

“…This finding has relevant physiological consequences. Indeed in vivo, intracellular recordings have shown that odontoblasts have a resting membrane potential around Ϫ80 mV, values comparable with excitable cells (24). Previous electrophysiological studies have described the presence of ion channels in odontoblasts whose activity was modulated by mechanical stimuli (5).…”

Transforming Growth Factor .BETA.1 Promotes Migration of Human Periodontal Ligament Cells through Heat Shock Protein 27 Phosphorylation

“…16) Dentinal healing and repair are the result of successive and interrelated processes that include proliferation, chemotaxis, and differentiation of dental pulp cells into odontoblasts, leading to reparative dentin formation. 17) However, the underlying mechanism of TGF-b1 responsible for regulating hPDL cell migration has not been fully elucidated. Because hPDL cells are responsible for tissue regeneration and mineralized tissue matrix formation, and cell migration are critical processes in tissue regeneration, it is valuable to clarify the precise mechanism of the cell migration of hPDL cells.…”

Efeito do VEGF na angiogênese pulpar e na apoptose

“…A espessura das fatias dentárias humanas constituiu-se, também, uma das preocupações, não pelo fato de se conseguir padronizar a espessura recomendada de 1,5 a 2mm 76,87,88,125 , mas em obter uma espessura adequada que proporcionasse, após os procedimentos de fixação e desmineralização, condições favoráveis para o corte histológico. Esse foi o nosso maior problema, pois inúmeras fatias dentárias foram perdidas durante esse procedimento.…”

“…Esse foi o nosso maior problema, pois inúmeras fatias dentárias foram perdidas durante esse procedimento. Os procedimentos de fixação (24h) e desmineralização (48h-72h) foram seguidos conforme dita o protocolo do Dr. Antony Smith e outros trabalhos referentes `a cultura de fatias dentárias 76,81,88,125 . Segundo informação do técnico Chris Strayhorn (Universidade de Odontologia de Michigan), o qual realizou os procedimentos histotécnicos referentes ao corte das amostras em parafina e coloração com HE, o problema das perdas das amostras poderia estar relacionado com a espessura da fatia dentária o qual, no primeiro experimento, foi de 2mm.…”

“…Não tivemos o objetivo de estendê-lo para períodos mais longos, como já visto em alguns trabalhos de cultura celular (MAGLOIRE; JOFFRE; BLEICHER 76 , 1996, SLOAN et al 125 , 1998 em dentes de ratos), pois os resultados obtidos em 7 dias ofereceram dados suficientes que instigaram ainda mais a realização do estudo in vivo, objetivo primordial desta pesquisa.…”