# Regenerative Endodontics as the Future Treatment of Immutative Permanent Teeth
## 3 Results
### Root Canal Disinfection
[46] described a case of REP failure after TAP application. Repeat treatment with calcium hydroxide (Ca(OH)\({}_{2}\)) and CHX as irrigating agents was successful. However, some researchers pointed out the risk of weakening the canal walls [44], a possible decrease in the antibacterial properties of calcium hydroxide in contact with inflammatory exudation in the root canal [47], risk of periapical tissue and stem cell damage due to high pH, and the possibility to induce mineralization in the root canal lumen [1]. [PERSON], comparing the effects of TAP, Ca(OH)\({}_{2}\), and formocresol as medicaments used in the endodontic treatment of immature permanent teeth, demonstrated the superior efficacy of TAP in promoting further root development [48]. According to some authors, TAP is biocompatible [49]. Furthermore, minocycline is proven to be non-cytotoxic, inhibit collagenases and metalloproteinases, and increase the anti-inflammatory cytokine II-10, whereas metronidazoleze and ciprofloxacin can stimulate fibroblast formation [50]. To reduce the risk of minocycline-induced crown discoloration, the paste should be applied very carefully into the canal so that it does not reach above the cementoenamel junction (CEJ) [44]. Some authors suggest the use of a self-etching bonding system to seal the dentinal tubules in the pulp chamber prior for paste application [51], the alternate use of amoxicillin [52] or cefaclor [53], or a dual-antibiotic paste (DAP) [54]. However, calcium hydroxide, used as an intracanal disinfecting dressing, also has many well-studied advantages. It was shown that the use of calcium hydroxide in combination with EDTA induces the release of TGF-1 and does not adversely affect the survival of stem cells from the apical papilla (SCAP), as is the case with TAP and high concentrations of NaOCl. On the contrary, it was demonstrated that by releasing growth factors, calcium hydroxide, embedded into dentine walls after irrigation, indirectly affects SCAP survival and proliferation [42; 55; 56]. It is also much easier to rinse it out completely from the root canal compared to TAP--it is speculated that, despite thorough irrigation, up to 80% of the triple antibiotic paste may remain in the root canal and still negatively affect stem cell survival [42; 57]. An alternative method of root canal disinfection was indicated by [PERSON] et al. [58]. In animal studies, they demonstrated, comparable to TAP, the antibacterial efficacy of propolisis used as an intracanal medicament in REP. So far, the available reports are dominated by protocols involving two visits with interference in the canal lumen, between which disinfectants are applied for one to four weeks [44]. However, this entails a risk of reinfection of the canal, which is why there are proposals for a single-visit procedure. One of the alternative methods may be photoactivated disinfection (PAD). It was successfully used in root canal disinfection of mature teeth [59; 60; 61; 62]. Attempts are being made to use it in REP [62; 63]. It is based on activating a photosensitizer (tolonium chloride or toluidine blue) with a low-power laser light at an appropriate wavelength. The energy released during this process causes the formation of a reactive oxygen species (ROS), which is responsible for the destruction of bacterial cells. This method is highly selective, non-toxic, and does not induce microbial resistance. In addition, the procedure is painless and quick. If necessary, the treatment may be repeated several times during one visit. It also has the advantage of performing the entire REP in a single visit, which minimizes the risk of contamination during subsequent tooth opening [62; 63; 64]. However, it requires appropriate instrumentation. Some researchers reported successful REPs performed in a single visit, using only rinsing disinfectants [65; 66]. Based on our initial studies, it should be noted that the phenomenon of extravascular neoangiogenesis was observed in treated and untreated adult teeth (Figure 2).