Pathway 13-9-1 Pulp Repair

Study Notes

Pulpal Repair

Pulpal repair involves the formation of tertiary dentin, a specialized type of dentin that forms as a protective barrier against external stimuli.
Pulp healing begins with macrophages removing debris, followed by the proliferation of fibroblasts, capillary buds, and collagen formation.
The formation of tertiary dentin depends on the type of stimulus, the type of odontoblasts involved, and whether the stimulus leads to the loss of original odontoblasts.
Tertiary dentin can be classified as reactionary dentin or reparative dentin.
Reactionary dentin forms when the original odontoblasts are stimulated and the tubules remain continuous. It forms in response to stimuli such as excessive wear, cavity preparation, or restorative materials.
Reparative dentin forms when the original odontoblasts are destroyed, and new odontoblast-like cells differentiate to form a new, less tubular, and more irregular dentin. The tubules are not continuous with the secondary dentin.
The release of growth factors, such as TGF- b , IGF-1 and IGF-2 , BMPs, VEGF during secondary dentin formation plays a crucial role in stimulating the differentiation of mesenchymal stem cells into reparative dentin and new blood vessels.
Calcium hydroxide, often used in apexification treatment, has a slight demineralizing effect on dentin, which releases TGF- b and accelerates reparative dentinogenesis.
Potential future applications of molecular biology in restorative dentistry include:
- Applying growth factors to dentin to stimulate peritubular dentin formation and occlusion of dentinal tubules.
- Transfecting pulpal fibroblasts with BMP-7 to stimulate increased production of this growth factor.
- Using specific amelogenin gene splice products (A 1 4 and A 2 4) to induce mineralization of root canals.
The formation of tertiary dentin can be considered a reparative process:
- It forms in response to injury and helps the pulp retreat behind a barrier of mineralized tissue.
- It has also been observed in normal, unerupted teeth, suggesting that tertiary dentin formation might be a natural process.