Regenerative endodontics

Regenerative endodontic procedures is defined as biologically based procedures designed to replace damaged structures such as dentin, root structures, and cells of the pulp-dentin complex. This new treatment modality aims to promote normal function of the pulp. It has become an alternative to heal apical periodontitis. Regenerative endodontics is the extension of root canal therapy. Conventional root canal therapy cleans and fills the pulp chamber with biologically inert material after destruction of the pulp due to dental caries, congenital deformity or trauma. Regenerative endodontics instead seeks to replace live tissue in the pulp chamber. The ultimate goal of regenerative endodontic procedures is to regenerate the tissues and the normal function of the dentin-pulp complex.

Before this treatment modality is introduced, apexification procedures using either immediate placement of mineral trioxide aggregate apical plug or long term-calcium hydroxide treatment were traditionally used to treat immature permanent tooth. Although these treatments often resolve the signs and symptoms of pathosis, they provide little to no benefit for continued root development. Further root growth, normal pulpal nociception and immune defense are impeded in the procedure of apexification.

To replace live tissue, either the existing cells of the body are stimulated to regrow the tissue native to the area or bioactive substances inserted in the pulp chamber. These include stem cell therapy, growth factors, morphogens, tissue scaffolds and biologically active delivery systems.

Closely related to the field of regenerative endodontics, are the clinical procedures apexification and apexogenesis. When the dental pulp of a developing adult tooth dies, root formation is halted leaving an open tooth apex. Attempting to complete root canal on a tooth with an open apex is technically difficult and the long-term prognosis for the tooth is poor.

Apexogenesis, (which can be used when the pulp is injured but not necrotic) leaves the apical one-third of the dental pulp in the tooth which allows the root to complete formation. Apexification, stimulates cells in the periapical area of the tooth to form a dentin-like substance over the apex. Both improve the long-term prognosis for a forming tooth over root canal alone.

Necrotic pulp and open apex can be revitalized with platelet rich fibrin.

Regenerative endodontics is founded by the seminal work by Dr. Ostby in the early 1960s. He hypothesized that the presence of blood clot within the root canal promotes healing of the pulp, hence maintaining the vitality of the pulp. This can be quite similar to the role of blood clot in other injury site in the healing process. To prove this hypothesis, mature teeth diagnosed with pulpal disease received pulp space debridement followed by enlargement of the apical foramen. Medicament dressing was placed and intracanal bleeding was evoked. Kloroperka obturation placed coronal to the formed blood clot. This study aimed to evaluate the role of the apical blood clot in the healing of apical periodontitis and pulp repair.

Patients were followed from a time period of 17 days to 3.5 years and the treated teeth were then extracted. The newly formed tissue were histologically examined. Resolution of symptoms of inflammation related to enlargement of foramen and overinstrumentation were observed in as early as 17 days. Resolution of apical periodontitis and signs and symptoms of inflammation and radiographic evidence of continued root development and apical narrowing were demonstrated in all teeth.