Regenerative Endodontic ProcedureEdit

Regenerative endodontic procedure (REP) is a contemporary approach within endodontics that seeks to restore health and function to an infected, nonvital tooth by encouraging the growth of biological tissue within the root canal system. Rather than simply sealing the canal, REP aims to promote tissue regeneration that can contribute to continued maturation of the root and a more resilient tooth structure, especially in immature teeth where conventional therapy may arrest development. The core concept relies on the interaction of stem cells, signaling factors, and a scaffold to reconstitute vital tissue inside the tooth. See also endodontics, regenerative medicine.

REP is most commonly considered for immature teeth (teeth with incompletely formed roots and open apices) presenting with pulp necrosis or severe pulpal inflammation, typically accompanied by apical periodontitis. In such cases, traditional root canal therapy is technically challenging because the thin dentinal walls and open apex provide little natural resistance to fracture or microbial leakage. By contrast, REP seeks to create conditions favorable to tissue ingrowth, potentially increasing root length and wall thickness and reducing the risk of fracture over time. See also immature tooth, pulp necrosis, apical periodontitis.

History and development

The idea of biologically based endodontic repair evolved from earlier concepts of apexification and canal disinfection. Apexification, historically used to manage nonvital immature teeth, relied on creating an apical barrier but did not promote continued root development. In the early 2000s and into the 2010s, reports and clinical protocols describing procedures that leverage a regenerative biology framework—disinfection, bleeding induction to supply stem cells, and a scaffold to guide tissue formation—began to accumulate. Since then, REP has become an increasingly discussed option among clinicians, with ongoing refinement of materials, disinfection regimens, and case selection criteria. See also apical papilla, dental stem cells.

Biological basis and components

Cells: Regeneration is thought to involve stem cell populations present in the apical region and surrounding tissues, notably the apical papilla and dental pulp stem cells. These cells can contribute to the formation of new tissue within the canal space when a conducive environment is provided. See also apical papilla, dental pulp stem cells.
Growth factors: Signaling molecules released during disinfection and bleeding create a microenvironment that supports cell recruitment, proliferation, and differentiation. See also growth factors.
Scaffold: A cellular scaffold, often formed by a blood clot initiated from intentional bleeding into the canal or by biomaterials used as a scaffold, provides a framework for tissue ingrowth. See also blood clot, bioceramic materials.
Disinfection: Effective microbial control is critical, as persistent infection impedes regeneration. Clinicians employ techniques and medicaments to minimize bacterial load while preserving viable tissue. See also calcium hydroxide, triple antibiotic paste.

Indications, limitations, and contraindications

Indications: REP is most commonly considered for immature teeth with necrotic pulp and apical periodontitis where continued root development would be advantageous. It may also be considered in selected mature teeth, particularly when conventional root canal therapy would compromise structural integrity or when a regenerative outcome is sought. See also immature tooth, apical periodontitis.
Limitations: Outcomes can be variable, and the tissue formed within the canal may be similar to pulp-like tissue rather than true dentin-pulp complex; long-term functional equivalence to the original pulp is a subject of ongoing study. Standardization of protocols and patient selection remains a topic of professional discussion. See also endodontic outcome.
Contraindications: Infections or conditions where delicate disinfection is unlikely to be achieved, or where the structural integrity of the tooth is severely compromised, may limit the feasibility or desirability of REP. See also apical periodontitis.

Techniques and materials

Disinfection: The initial phase emphasizes thorough disinfection of the canal space while attempting to minimize harm to resident stem cells. Agents such as calcium hydroxide or other antimicrobial regimens may be used, with attention to balancing antimicrobial efficacy and tissue preservation. See also calcium hydroxide.
Induction of a blood clot: A central element is inducing hemorrhage into the canal to bring stem cells and growth factors into the space, creating a natural scaffold. See also blood clot.
Scaffolds and materials: Besides natural blood clots, clinicians may use bioceramic sealers or scaffolds to support regeneration, aiming to create a stable environment for tissue growth. Common materials include mineral trioxide aggregate (MTA) and other bioceramics. See also mineral trioxide aggregate, bioceramic materials.
Antibiotic medicaments: In some protocols, intracanal medicaments such as triple antibiotic paste are employed to control infection, though concerns about tissue toxicity and tooth discoloration have led to ongoing evaluation of alternatives. See also triple antibiotic paste.
Coronal sealing: Robust coronal restoration is critical to protect the treated tooth from microleakage and reinfection, ensuring an environment conducive to regeneration. See also coronal restoration.

Outcomes and evidence

Clinical outcomes: Short- to medium-term follow-ups have reported continued root development, increased root wall thickness, and positive tooth survival in many cases. However, long-term data on true functional restoration of the original pulp-dentin complex are still developing, and results can be case-dependent. See also tooth survival.
Radiographic and histologic findings: Imaging may show continued root maturation or increasing radiolucency resolution. Histologic confirmation of true pulp regeneration is achievable only in select experimental or rare clinical circumstances; more often, repair with tissue that supports function is observed. See also apical development.
Comparisons: REP contrasts with apexification and conventional root canal therapy. Each approach has distinct goals, risk profiles, and suitability depending on tooth maturity, infection status, and fracture risk. See also apical closure, root canal therapy.

Controversies and debates

True regeneration versus repair: Critics point out that the tissue formed within the canal may be pulp-like or fibrous rather than a definitive dentin-pulp complex, raising questions about the long-term functional equivalence to native pulp tissue. Supporters emphasize the clinical benefits of continued root development and reduced fracture risk in open-apex teeth.
Standardization and reproducibility: Protocols vary in disinfection choices, intracanal medicaments, and scaffolding strategies, which can influence outcomes. Ongoing research seeks to establish standardized recommendations. See also regenerative endodontics.
Economic and access considerations: Regenerative approaches can involve specialized materials and longer or more complex procedures, which may impact cost and access in different health systems. See also health economics.
Competing paradigms: For some teeth, conventional root canal therapy or apexification may provide predictable results with established risk profiles, leading clinicians to weigh REP against tried-and-true methods on a case-by-case basis. See also root canal therapy.

Clinical considerations and practice guidelines

Case selection: Successful REP depends on selecting teeth where continued root maturation would meaningfully reduce fracture risk and improve long-term viability, while ensuring infection control is achievable.
Technique refinement: Ongoing professional education and adherence to evolving guidelines help clinicians minimize variability and optimize outcomes. See also clinical guidelines.
Outcome monitoring: Regular follow-up with clinical examination and radiographs is standard to assess healing, root development, and tooth stability over time. See also radiographic follow-up.