The concept of regenerating dental pulp seemed like science fiction a decade ago. Today, regenerative endodontic procedures (REPs) are recognized treatment options in AAE guidelines, with expanding indications and improving outcomes. For practitioners still viewing this as experimental, the evidence base has matured significantly.

This review synthesizes findings from 47 clinical studies and 3 systematic reviews published since 2022, focusing on practical applications for practicing endodontists and general dentists managing pulpal pathology.

Current Evidence: What We Know Works

REP success rates for immature permanent teeth with pulpal necrosis now exceed 90% in properly selected cases, with continued root development observed in 80-85% of teeth. Five-year follow-up data from multicenter studies confirm these outcomes are durable.

The mechanism involves evoked bleeding from periapical tissues, which introduces stem cells from the apical papilla (SCAP) into the decontaminated canal space. These cells, combined with signaling molecules from dentin and scaffold formation from the blood clot, enable tissue regeneration.

Importantly, histological studies reveal that "regenerated" tissue is often more similar to cementum-like or bone-like tissue than true pulp. But from a clinical perspective, the outcomes—continued root development, resolution of apical pathology, positive sensibility testing in some cases—validate the approach regardless of histological classification.

Patient Selection: The Key to Success

Case selection remains the most critical success factor. Ideal candidates are young patients (under 18) with immature permanent teeth showing open apices (greater than 1mm diameter) and necrotic pulps secondary to trauma or caries.

Contraindications include teeth with complete root formation (where apexification or traditional RCT remains preferred), active acute infections requiring immediate drainage, and patients unable to comply with multi-visit protocols.

Emerging evidence supports expanded indications: some practitioners report success in mature teeth with apical periodontitis, though outcomes are less predictable and evidence is limited. We recommend restricting REP to immature teeth until stronger evidence supports broader application.

Protocol Evolution: What's Changed

The original AAE protocol using triple antibiotic paste (TAP) remains effective but is being refined. Concerns about minocycline-induced crown discoloration have led to modified protocols using double antibiotic paste (DAP) without minocycline, or calcium hydroxide alternatives.

Recent research suggests that lower antibiotic concentrations (0.1-1.0 mg/mL) achieve adequate disinfection while preserving stem cell viability better than the original 1.0 g/mL concentration. Some practitioners now use antibiotic-free protocols with enhanced irrigation.

Scaffold materials beyond evoked bleeding are under investigation. Platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and synthetic hydrogels show promise in laboratory studies, with early clinical trials reporting comparable or superior outcomes to blood clot scaffolds.

Practical Implementation

For general dentists: REP is within the scope of general dentistry for straightforward cases, though referral to endodontists is appropriate when clinical complexity or practitioner experience is limited. The multi-visit nature (typically 2-3 appointments over 4-6 weeks) requires scheduling flexibility.

For endodontists: REP should be offered to appropriate candidates as a first-line option, not as a last resort after traditional treatment fails. The treatment planning conversation should address realistic outcome expectations, including the possibility of requiring conventional RCT if regeneration is unsuccessful.

Follow-up is essential and different from traditional endodontic recalls. Serial radiographs at 6, 12, and 24 months track root development. Sensibility testing, while not universally positive post-REP, provides valuable outcome information when possible.

Future Directions

The frontier of regenerative endodontics includes cell-based therapies using cultured dental pulp stem cells, growth factor delivery systems, and dentin-derived bioactive materials. While most remain investigational, some may reach clinical application within 3-5 years.

For now, the evidence strongly supports REP as a valuable treatment modality for immature necrotic teeth. Practitioners not offering this option are doing a disservice to young patients who could benefit from continued root development rather than permanent dependence on obturation materials.

The key takeaway: regenerative endodontics has graduated from experimental to established. The question isn't whether to incorporate it into practice, but how to implement it optimally for appropriate patients.