# Regenerative Endodontics as the Future Treatment of Immutative Permanent Teeth
## 3 Results
### Comparison of Methods and Effects of REP
Ultrasound-activated 5% NaOCl was used for disinfection, and 17% EDTA was the final irrigant. After bleeding of the apical region, MTA was applied, and the cavity was restored with GI. Follow-up visits were made after 6 weeks and 3, 6, 12, and 18 months. The tooth remained asymptomatic. Radiographs showed root wall growth, which manifested itself in an increase in its length and thickness and closure of the apical opening. In 2016, [PERSON] et al. [65] attempted to treat three immature mandibular molars with pulp necrosis in children aged eight and nine. The procedure was performed in a single visit. After disinfection with 2.5% NaOCl, PRP was applied to the canals, which were then closed with Biodentine, and the cavities were then filled with composite. Further root development and an absence of pathological symptoms were observed. In 2017, [PERSON] et al. [18] conducted a comparative analysis of the efficacy of using PRP, PRF, and BC. Twenty immature teeth with necrotic pulp were included in each group. The canals, after careful instrumentation, were rinsed with 5.25% NaOCl and filled with TAP for three weeks. At the next visit, PRP, PRF, or BC was applied to the canal. The teeth were closed with intermediate restorative material (IRM). After 3, 6, 9, and 12 months of observation, none of the patients showed any pathological clinical symptoms or the development of new periapical lesions or an increase in its size. The highest healing efficiency of periapical lesions was recorded after PRP application. In 2018, [PERSON] et al. [103] published a REP case in which 3% NaOCl and 17% EDTA were used in the irrigation protocol and Ca(OH)\({}_{2}\) was an intracanal medication. PRF and MTA were utilized as a cellular scaffold, and the tooth was closed with composite resin. Follow-up visits at 1, 6, and 12 months showed healing of the periapical lesions, growth of the root wall in thickness, and closure of the apical opening. After 12 months, the tooth had to be extracted due to fracture; it underwent histopathological examination, which revealed cement-like tissue on the root canal walls. In 2019, [PERSON] et al. [63] performed a single-visit REP in the central upper incisor. Canal disinfection was performed using 1.5% NaOCl and the PAD method. Seventeen percent EDTA was used as the last irrigating solution. After bleeding of the periapical region, the clot was covered with a collagen membrane and MTA. Follow-up visits were performed after 3, 6, 9, and 12 months. Complete root development was observed after 12 months of follow-up. In 2020, [PERSON] et al. [104] described a case of REP treatment of two central incisors with a 12-year follow-up. It consisted of 2.5% NaOCl, 17% EDTA, and 2% CHX gel used for disinfection (for one week), and then DAP was applied to one tooth and Ca(OH)\({}_{2}\) to the other (for three weeks). BC and MTA were employed as a scaffold, and the teeth were restored with RMGI. The patient reported no pain for 12 years, no reaction to palpation or percussion, and cone beam computed tomography (CBCT) revealed root growth in length and thickness, increased calcification, and a root shape defect. The authors emphasized that there was no mention in the available literature of possible tissue invagination during root formation due to REP. As a probable cause, they suggested the compression or stretching of [PERSON]'s sheath as a result of trauma, which led to pulp necrosis in the examined tooth. In 2020, [PERSON] et al. [105] published a study of 47 teeth undergoing REP, which was carried out between 2009 and 2017. Of the 47 evaluated cases, only in three, the procedure failed. For disinfection, 2% ultrasound-activated NaOCl and, initially, TAP was used, with DAP after 2015. BC with MTA was used as a carrier. Teeth were restored with composite resin. Cases of ankylosis were documented in teeth undergoing the procedure, but this could be related to the trauma that led to the endodontic treatment. Discoloration of tooth crowns was noted, probably due to obliteration, the use of minocycline, or MTA.