# Endodontic Regenerative Procedures in Necrotic Adult Teeth
## 3 Results  
After the selecting process, 3 randomized clinical trials and 20 case reports were finally included. Adult teeth with closed apex constitute the population of the 3 randomized clinical trials, where REP was performed in 62 teeth from patients aged 16 to 58 years (Table 4). In addition, 5 case reports treated 8 mature teeth of 5 patients aged 12 to 21 years. (Table 5). On the other hand, no randomized clinical trials performed REP exclusively in immature adult teeth, so the available evidence for these teeth is limited to 16 case reports, where 26 teeth from 22 patients aged 11 to 25 years were treated (Table 6). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Case Report** & **Patient’s Age** & **Tooth Treated** \\ \hline
1. [PERSON] 2020 [40] & 16 & 4.7 \\ \hline  & 23 & 1.2 \\ \cline{2-3}
2. [PERSON] 2020 [41] & 21 & 2.1 \\ \hline  & 14 & 1.2 \\ \cline{2-3}
3. [PERSON] 2020 [42] & 14 & 1.1 \\ \cline{2-3}  & 13 & 1.1 \\ \hline
4. [PERSON] 2020 [43] & 11 & 1.2 and 2.2 \\ \hline
5. [PERSON] 2020 [44] & 21 & 1.1 \\ \cline{2-3}
6. [PERSON] 2019 [45] & 15 & 1.1 \\ \cline{2-3}
7. [PERSON] 2018 [46] & 29 & 1.2 \\ \hline
8. [PERSON] 2018 [47] & 18 & 1.1 \\ \hline
9. [PERSON] 2018 [48] & 15 & 2.1 \\ \hline
10. [PERSON] 2017 [49] & 11 & 2.1 \\ \hline
11. [PERSON] 2018 [50] & 13 & 1.1, 1.2, 2.1 and 2.2 \\ \hline
12. [PERSON] 2017 [51] & 20 & 2.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Randomized Clinical Trials where REP in adult permanent mature teeth were performed, according to age group and number of teeth treated. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Randomized Clinical Trial** & **Age Group** & **Number of Teeth Treated** \\ \hline
1. [PERSON] 2020 [32] & 16–58 & 18 \\ \hline
2. [PERSON] 2020 [33] & 20–40 & 18 \\ \hline
3. [PERSON] 2019 [34] & 20.58 \(\pm\) 2.53 & 26 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Case reports where REP in adult permanent mature teeth were performed, according to patient’s age and tooth treated, designated following the World Dental Federation notation (FDI notation). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Case Report** & **Age Group** & **Tooth Treated** \\ \hline
1. [PERSON] 2020 [35] & 19 & 1.2 \\ \hline
2. [PERSON] 2019 [36] & 20 & 1.1 and 1.2 \\ \hline
3. [PERSON] 2018 [37] & 21 & 2.1 and 2.2 \\ \hline
4. [PERSON] 2016 [38] & 16 & 1.1 \\ \hline
5. [PERSON] 2017 [39] & 12 & 3.1 and 4.1 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Case reports where REP in adult permanent immature teeth were performed, according to patient’s age and tooth treated, designated following the World Dental Federation notation (FDI notation). to young teeth: decreased revascularization capacity, lower potential of stem cells and, in general, smaller diameter of the apical constriction. The proposed protocol, available in Supplementary File S3, is based on the ones from the AAE [57] and the ESE [4] for immature teeth, adding modifications derived from the protocols carried out in the randomized clinical trials analyzed, and considering the trend of most of the clinicians included in this review and the available evidence. Two key points of the protocol will be criticized: 1. Instrumentation and ideal apical diameter. 2. Irrigation and intracanal medication. Regarding instrumentation, some clinicians consider that a minimal mechanical debridement is necessary to facilitate the destruction of biofilms [58], while others rely on chemical debridement using disinfectants and the use of intracanal medication to achieve the complete disinfection of the canal system [59]. From the studies reviewed, it is concluded that the majority of clinicians perform a minimal instrumentation of the canals. The instrumentation techniques and instruments used vary depending on the state of development of the tooth, predominantly reciprocating rotary instrumentation technique for the treatment of mature teeth, and manual technique with K and H files for immature teeth.