# Regenerative Endodontics as the Future Treatment of Immutative Permanent Teeth
## 3 Results
### Proposed Protocol of REP  
As it can be inferred from this review, many REP protocols have been proposed, and no single optimized algorithm has emerged. We developed a procedure that is based on the literature and constitutes a compromise between safety and feasibility. Therefore, the solutions reported in the literature [18; 62; 66; 101] that are debatable, such as irrigation with high concentrations of NaOCl, were not included. TAP showed high efficacy against pathogens present in the root canal [40; 41] and is, therefore, recommended in many protocols [18; 35; 101; 105]. However, it shows potential side effects, such as the risk of developing bacterial resistance, coronal discoloration, cytotoxicity, and difficulty in removal from the root canal [40; 41]. Thus, it seems that using calcium hydroxide as a dressing with proven antimicrobial efficacy, which is also readily available and widely used in dentistry, is a better option [44]. So far, despite the ongoing debate, the superiority of any of the REP methods used (BC, PRP, PRF) is yet to be unequivocally demonstrated [18]. Blood clot formation is a simple method that does not require drawing blood from the patient or having specialized equipment, and thus can be performed in any dental office. The details of the proposed protocol are presented below (Table 5).  
The first visit: After local anesthesia, isolation with a rubber dam and disinfection of the operating field with iodine solution, endodontic access should be performed and the tooth chamber secured with a bonding system or Biodentine material (if TAP is used). Irrigation of the canal can be achieved with a 2% NaOCl solution (20 mL, 5 min), followed by 17% EDTA (20 mL, 5 min) and the same amount of 0.9% NaCl. The endodontic needle should be placed 1-2 mm from the apex and the working length determined based on the intraoperative radiograph and confirmed by endometer indication. The effect of NaOCl can be enhanced by applying ultrasound or by heating the solution to 37 \({}^{\circ}\)C. After drying the canal with sterile paper points, calcium hydroxide should be applied intracanally. The canal should be secured with a sterile cotton pad/sponge/Teflon, and the tooth should be sealed, e.g., with glass ionomer cement. It is recommended to monitor the entire procedure using magnification, working with a dental microscope.  
The second visit should take place after two to four weeks. If symptoms suggesting an ongoing inflammatory process persist or occur, the protocol from the first visit should be repeated. In the absence of symptoms, one can proceed to the final REP. For this purpose, the patient should be anesthetized (vasoconstrictors are not recommended to facilitate bleeding), the surgical field isolated and disinfected, and the temporary filling removed. Irrigation should be carried out with 0.9% NaCl (20 mL, 5 min) to wash out any residual TAP from the canal completely. Rinsing should be completed with 17% EDTA (20 mL, 5 min). After drying the canal with sterile paper points, bleeding of the apical region must be induced, e.g., by inserting a sterile, bent #25 K-file 2 mm beyond the apex and then waiting for clot formation for approx. 15 min. The clot should be located approx. 3 mm below the CEJ. An alternative method is to use PRP or PRF. Additionally, a collagen membrane can be used to help to stabilize the clot. The clot should then be covered with approximately 3-4 mm of MTA/Biodentine and sealed, e.g., using RMGI and composite. If MTA is used, the final filling is possible on the next visit. Finally, it is necessary to close the canal tightly and restore the tooth crown.  
Follow-ups: Follow-up appointments, including clinical and radiological examination, should take place every 3 months during the first year, then every 6 months for two years, and then every 12 months for five years.