Regenerative endodontics
The ultimate goal of regenerative endodontic procedures is to regenerate the tissues and the normal function of the dentin-pulp complex.
These include stem cell therapy, growth factors, morphogens, tissue scaffolds and biologically active delivery systems.
To prove this hypothesis, mature teeth diagnosed with pulpal disease received pulp space debridement followed by enlargement of the apical foramen.
It has been proven that the vitality of dental pulp in immature teeth is preserved and it is free of signs and symptoms of disease even though it has sustained traumatic injuries such as avulsion and intrusion.
Up to 35 percent of children between the ages of 7 and 15 years experience traumatic dental injuries when the root development of the permanent teeth are still incomplete.
Apexification procedures[17] were traditionally used to treat teeth with pulpal pathology to resolve the signs and symptoms of pulp pathosis.
Long term calcium hydroxide treatment[4] or placement of mineral trioxide aggregate[3] apical plug was performed.
However, these treatments provide little to no benefit for continuous root development,[18] leaving a thin fragile dentinal wall.
These mesenchymal stem cells are found in dental pulp [20][21] (DPSCs), the apical papilla [22][23](SCAP) and even in the inflamed periapical tissue [24] (iPAPCs) collected during endodontic surgical procedures.
This issue is significant for regenerative procedures, since the non-collagenous proteins contained within dentin include several crucial growth factors such as TGF-β.
Therefore, the selection of irrigants as well as their sequence may play essential roles in conditioning dentin into a surface capable of supporting differentiation of a desired cell phenotype.
[38] The term revascularization arose from the trauma literature, and the observation that pulp in teeth with transient or permanent ischemia could have re-establishment of its blood supply in particular cases.
However, these findings do not include the intentional use of tissue engineering principles despite their significant influence in developing the contemporary regenerative endodontic procedures.
In contrast, contemporary regenerative endodontic procedures consider the presence of an enriched source of stem cells within the apical tissues, their delivery into root canal systems, and the intentional release and use of local growth factors embedded into the dentin.
Since high concentrations of stem cells are delivered into the root canal space when lacerating the apical papilla in the immature permanent tooth,[39] this clinical procedure accomplishes one major element of the triad of tissue engineering.
Ongoing research has evaluated combinations of stem cells, growth factors, and scaffolds that result in histological regeneration of pulp tissues.
[43] Therefore, a focus on “revascularization” would disregard the potential role of growth factors and scaffolds in histological recapitulation of the pulp-dentin complex.
Although angiogenesis and the establishment of a functional blood supply is a key feature in the maintenance and maturation of a regenerating tissue, positive responses to pulp sensitivity tests such as cold or EPT have been reported in some of the published cases.
Thus, the primary therapeutic goal of regenerative endodontic procedures is to promote the healing, survival and function of the tooth.
The primary goal of any endodontic therapy is the resolution of infection and the signs and symptoms of inflammation leading to apical periodontitis.
Therefore, complete cleaning and shaping as well as obturation of these teeth are difficult or sometimes impossible, due to high risk of fracture during the procedure [48] Clinical outcome of regenerative endodontics can be observed within 6 months of treatment such as no pain, soft-tissue swelling, or sinus tract.
[49] Regenerative endodontics has 3 critical steps: adequate disinfection of the root canal system, induction of bleeding through overinstrumentation to create a scaffold for stem cells, and coronal sealing of the blood clot with a biocompatible material, such as mineral trioxide aggregate.
Then, an absorbable collagen barrier is placed above the blood clot followed with mineral trioxide aggregate and glass ionomer cement.
The patient is then recalled after 7 days to ensure setting of the filling material of mineral trioxide aggregate, and replacement of the glass ionomer cement with composite resin.
Disinfecting agents for regenerative procedures include sodium hypochlorite, antibiotic or calcium hydroxide dressings.
Therefore, sodium hypochlorite is advised to be used at a lower concentration so as to achieve the optimum effect for antimicrobial activity and differentiation of the stem cells.
There are some benefits of regenerative endodontics such as: revitalization of the tooth, continued root development and, potentially, increasing fracture resistance.
Regenerative endodontic treatment helps in true pulpal regeneration and re-establishment of the pulp-dentin complex, which leads to revitalisation of the tooth.
[1] King's College London published in January 2017 on the regeneration of dentine with collagen sponge filled with glycogen synthase kinase (GSK-3) .
