ULTRASTRUCTURAL AND IMMUNOHISTOCHEMICAL ASSESSMENT OF MESENCHYMAL STEM CELL ATTACHMENT AND BEHAVIOUR TO ROOT DENTIN AFTER DENTIN CONDITIONING WITH VARIOUS AGENTS ABSTRACT
Project no. 356 · Status: Kapanmış · 2017
Summary
The primary goal of the regenerative endodontic treatment is to regain vitality and function of pulp-dentin complex which lost due to trauma or microbial contamination. By this way, root development will continue and teeth will function as an organ in its lifespan. EDTA has been considered the gold standard in regenerative endodontic treatments. The aim of this study was to evaluate the effects of different dentin conditioning agents alternative to EDTA on mesenchymal stem cell attachment and behaviour and investigate their effects on the newly formed tissues after regenerative endodontic treatments in vivo by histochemical and immunohistochemical methods. In the in vitro part of our study root sections of extracted human single rooted incisors were used. Crown sections of extracted teeth were removed under water cooling. Then roots were cut corono-apically into two fragments under water cooling. Root fragments were irrigated with control (distilled water) and acid groups (EDTA, citric acid, phytic acid, phoshoric acid). After irrigation, medium containing mesenchymal stem cells were seeded on root fragments for 3 days. After three days of incubation period fragments were collected and investigated under scanning electron microscope (SEM) for MSC attachment and behaviour. Acid solutions used in this in vitro study showed no advers effects to MSC attachment and proliferation to root dentin. Round, oblong, flattened and well attached type cell morphology were observed. In the in vivo part of our study, root sections of extracted human incisor teeth were used. Crowns sections of extracted teeth were removed from roots under water cooling. Root canals were enlarged by endodontic files and approximately 3-4 mm length of root fragements were cut under water cooling. Root fragments were irrigated with the groups including control and acid solutions (distilled water, EDTA, citric acid, phytic acid, phosphoric acid). After irrigation narrow end of the canals were sealed with 1-2 mm thickness of MTA. In the first half of the groups only PLG scaffolds were inserted into the root fragments. In the second half of the groups, MSCs were seeded onto PLG scaffolds and then inserted into root fragments. Root fragments were implanted into the subcutaneous space of immunodeficient mice dorsum (2 teeth for each mice). Two months after implantation, mice were sacrificed and root fragments were evaluated by histochemical and immunohistochemical stainings. Pulp-like tissues were observed in the groups which include acid application and MSC seeding. The highest density stainings with odontoblast markers were observed in the phosphoric acid + MSC application group. We conclude that phosphoric acid could be an alternative conditioning agent to EDTA, which is considered as golden standard, in regenerative endodontic treatments.