ABSTRACT
The repair of dental pulp by direct capping with calcium hydroxide or by implantation of bioactive extracellular matrix (ECM) molecules implies a cascade of four steps: a moderate inflammation, the commitment of adult reserve stem cells, their proliferation and terminal differentiation. The link between the initial inflammation and cell commitment is not yet well established but appears as a potential key factor in the reparative process. Either the release of cytokines due to inflammatory events activates resident stem (progenitor) cells, or inflammatory cells or pulp fibroblasts undergo a phenotypic conversion into osteoblast/odontoblast-like progenitors implicated in reparative dentin formation. Activation of antigen-presenting dendritic cells by mild inflammatory processes may also promote osteoblast/odontoblast-like differentiation and expression of ECM molecules implicated in mineralization. Recognition of bacteria by specific odontoblast and fibroblast membrane receptors triggers an inflammatory and immune response within the pulp tissue that would also modulate the repair process.
Subject(s)
Dental Pulp/physiopathology , Inflammation/physiopathology , Regeneration/physiology , Animals , Dendritic Cells/physiology , Dental Caries/physiopathology , Dental Pulp/immunology , Extracellular Matrix Proteins/physiology , Humans , Leukocyte Common Antigens/analysis , Odontoblasts/physiologyABSTRACT
Direct capping of bioactive molecules or implantation of these molecules in the pulp may induce the formation of reparative dentin and coronal or radicular pulp mineralization. In this review, we summarize what is known and/or assumed on the biological mechanisms of these therapies. We report on the effects which were obtained experimentally in rat maxillary molars by implantation of Bone Sialoprotein (BSP)/collagen pellets and Specific Amelogenin Gene Splice Products [A+4] and [A-4]) adsorbed on agarose beads. The effects were compared with those of BMP-7 (OP-1) and Ca(OH)2. Depending on the molecule that was used, we obtained either the formation of a dentin bridge, or the filling of the pulp in the mesial part of the coronal pulp chamber, or the total mineralization of the root canal. These molecules may provide new therapeutic tools in the next future in dentistry.
