A pulp polyp, also known as chronic hyperplastic pulpitis, is a "productive" (i.e., growing) inflammation of dental pulp in which the development of granulation tissue is seen, and is characterised by the overgrowth of the tissue outside the boundary of a tooth's pulp chamber. A pulp poly may be found in an open carious lesion (tooth cavity), in a fractured tooth, or when a dental restoration is missing. Due to lack of intrapulpal pressure in an open lesion, pulp necrosis does not take place as would have occurred in a closed caries case.
The condition is more commonly seen in children and young adults. A good vascular and immune supply is necessary for such a condition to develop.