# Regenerative Endodontics as the Future Treatment of Immutative Permanent Teeth
## 4 Discussion  
REP probably represents the future of treatment of immature permanent teeth with pulp necrosis. The undoubted advantage over the standard apexification procedure using calcium hydroxide and MTA is the possibility of further root development, its growth in length and thickness, and closing of the apical foramen. The fundamental prerequisite for the success of the procedure is the correct qualification of the patient, effective disinfection \begin{table}
\begin{tabular}{c c c} \hline \hline
**First Appointment** & \
\begin{tabular}{c} **Second Appointment** \\ **(Only in the Absence of Signs of Inflammation)** \\ \end{tabular} &
\begin{tabular}{c} **Follow-Up** \\ **(Clinical and Radiological** \\ **Examination)** \\ \end{tabular} \\ \hline
1. Local anesthesia (may be done with & 1. Local anesthesia (3\% mepivacaine & 1. After three months \\ vasoconstrticr) & without vasoconstrticr) & 1. After three months \\ \hline
2. Isolating the operating field with a rubber & 2. Isolating the operating field with a rubber dam, & 2. After six months \\ dam, disinfecting with iodine solution & disinfecting with iodine solution & 2. After six months \\ (Povidone/Betadine) & (Povidone/Betadine) & 2. After six months \\ \hline
3. Endodontic access (sterile drills) & 3. Reopening of the tooth (sterile drills) & 3. After nine months \\ \hline
4. Intra-chamber application of a bonding & 4. Irrigation with 20 mL of 0.9\% NaCl (5 min), & 4. After 12 months \\ system or Biodentine * & 20 mL of 17\% EDTA (5 min) & 4. After 12 months \\ \multicolumn{4}{l}{* If TAP is used} & 20 mL of 17\% NaCl (5 min) & \\ \hline
5. Irrigation with 20 mL of 2\% NaCl (5 min, & \\ ultrasound activation), 20 mL of 17\% EDTA & 5. Draining the canal with sterile paper points & 5. Every six months \\ (5 min), 20 mL of 0.9\% NaCl (5 min) & 6. Inducing bleeding of the apical area * (e.g., sterile, & \\ \multicolumn{4}{l}{6. Draining the canal with sterile} & \#25 K-file, 2 mm beyond the apex), clot formation & \\ \multicolumn{4}{l}{paper points} & (15 min), collagen membrane application & \\ \multicolumn{4}{l}{* Or PRP/PRF application} \\ \hline
7. Calcium hydroxide application (or & \\ TAP/DAP—not recommended) & 7. Application of 3–4 mm MTA/Biodentine to the clot & \\ \hline
8. Tight temporary filling, e.g., RMGI & 8. Tight permanent filling (RMGI, composite) & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: REP—proposed protocol. of the root canal, and tight closure of the cavity. Despite intensive research carried out worldwide, this procedure still requires refinement and standardization of the treatment protocol. There are also some limitations, such as the lengthy treatment time and the need for the patient to attend numerous follow-up appointments. Complications, such as crown discoloration, tooth fracture, ankylosis, calcification/obliteration of the root canal lumen [89], periapical tissue inflammation, or lack of further root growth, can also be expected in some cases [106]. The use of calcium silicate-based cements (CSCs), such as MTA or Biodentine, was shown to contribute to crown discoloration, with Biodentine contributing significantly less than MTA. The mechanism of action for MTA is associated with the oxidoreductase potential of bismuth oxide, which, when in contact with strong oxidizing agents, such as sodium hypochlorite or collagen, causes tooth discoloration. In addition, direct contact of MTA with blood was shown to exacerbate discoloration. Another disadvantage of MTA is its long setting time (2 h and 45 min), which increases its porosity and, as a consequence, increases blood absorption and causes greater discoloration of the tooth crown. The prevalence of Biodentine over MTA is undoubtedly due to the lack of bismuth oxide in its composition, a much shorter setting time (12 min), and a lower rate of tooth crown discoloration. There are also reports in the recent literature of other CSCs, also with shorter setting times than MTA, which may also be good alternatives; these include, for example, TotalFill or PCM.