Challenges in Regenerative Endodontics

Various methods and different materials have been suggested to dealwith teeth having immature apices and necrotic pulp. In most of thesetreatment modalities root length and root dentin thickness remainunchanged and consequently, such teeth are susceptible to root fracture.The aim of regenerative endodontics procedures (REPs) in the treatmentof teeth with incomplete root formation and necrotic pulp is to replacethe irreversibly inflamed pulp tissue with newly regenerated tissue inan attempt to stimulate root maturation. The principle of REPs is basedon the tissue engineering triad, including (i) stem cell, (ii) scaffold, and(iii) signal molecules. The prerequisite of REPs is chemical disinfectionof the root canal system that achieves through profuse irrigation usingsodium hypochlorite and the placement of an antibacterial paste insidethe root canal system without mechanical instrumentation to avoidsmear layer formation that may block the release of growth factors fromroot dentin. In addition, it has been suggested to use the triantibioticpaste as an intracanal medication between the first and the secondappointment. However, due to the unique anatomy of the root canalsystem, the disinfection of the entire root canal system without injuringthe surrounding stem cells is almost impossible. During the secondappointment, a blood clot is induced inside the canal to act as a scaffoldfor regeneration and then the coronal access cavity is sealed with abioactive calcium silicate cement to prevent bacterial penetration andto allow regeneration in a bacteria-free environment. The material usedto provide the bacteria-tight seal in this context is important as it shouldideally have the ability to upregulate signaling molecules and provokeregeneration. In addition, since it is not practical to circumvent the bloodcontamination, the sealing capability and basic physical properties of thematerial should not be jeopardized by moisture and/or blood exposure.More recently, the use of platelet-rich plasma and/or platelet-rich fibrinrather than blood clot has been suggested. In this presentation, theclinical consideration of REPs by emphasizing on the clinical outcomeare reviewed and the recently published evidence about REPs will becritically appraised.

کلیدواژه ها:

Regenerative endodontics ، Stem cells