Marginal adaptation, physicochemical and rheological properties of treated dentin matrix hydrogel as a novel injectable pulp capping material for dentin regeneration

Preparation and characterization of bovine dental pulp-derived extracellular matrix hydrogel for regenerative endodontic applications: an in vitro study

BACKGROUND

The use of biological scaffolds in regenerative endodontics has gained much attention in recent years. The search for a new biomimetic scaffold that contains tissue-specific cell homing factors could lead to more predictable tissue regeneration. The aim of this study was to prepare and characterize decellularized bovine dental pulp-derived extracellular matrix (P-ECM) hydrogels for regenerative endodontic applications.

METHODS

Freshly extracted bovine molar teeth were collected. Bovine dental pulp tissues were harvested, and stored at -40º C. For decellularization, a 5-day protocol was implemented incorporating trypsin/EDTA, deionized water and DNase treatment. Decellularization was evaluated by DNA quantification and histological examination to assess collagen and glycosaminoglycans (GAGs) content. This was followed by the preparation of P-ECM hydrogel alone or combined with hyaluronic acid gel (P-ECM + HA). The fabricated scaffolds were then characterized using protein quantification, hydrogel topology and porosity, biodegradability, and growth factor content using Enzyme-linked immunosorbent assay (ELISA): transforming growth factor beta-1(TGF-β1), basic fibroblast growth factor (bFGF), bone morphogenetic protein 2 (BMP-2) and vascular endothelial growth factor (VEGF).

RESULTS

Decellularization was histologically confirmed, and DNA content was below (50 ng/mg tissue). P-ECM hydrogel was prepared with a final ECM concentration of 3.00 mg/ml while P-ECM + HA hydrogel was prepared with a final ECM concentration of 1.5 mg/ml. Total protein content in P-ECM hydrogel was found to be (439.0 ± 123.4 µg/µl). P-ECM + HA showed sustained protein release while the P-ECM group showed gradual decreasing release. Degradation was higher in P-ECM + HA which had a significantly larger fiber diameter, while P-ECM had a larger pore area percentage. ELISA confirmed the retention and release of growth factors where P-ECM hydrogel had higher BMP-2 release, while P-ECM + HA had higher release of TGF-β1, bFGF, and VEGF.

CONCLUSIONS

Both P-ECM and P-ECM + HA retained their bioactive properties demonstrating a potential role as functionalized scaffolds for regenerative endodontic procedures.

Hard tissue formation in pulpotomized primary teeth in dogs with nanomaterials MCM-48 and MCM-48/hydroxyapatite: an in vivo animal study

BACKGROUND

This animal study sought to evaluate two novel nanomaterials for pulpotomy of primary teeth and assess the short-term pulpal response and hard tissue formation in dogs. The results were compared with mineral trioxide aggregate (MTA).

METHODS

This in vivo animal study on dogs evaluated 48 primary premolar teeth of 4 mongrel female dogs the age of 6-8 weeks, randomly divided into four groups (n = 12). The teeth underwent complete pulpotomy under general anesthesia. The pulp tissue was capped with MCM-48, MCM-48/Hydroxyapatite (HA), MTA (positive control), and gutta-percha (negative control), and the teeth were restored with intermediate restorative material (IRM) paste and amalgam. After 4-6 weeks, the teeth were extracted and histologically analyzed to assess the pulpal response to the pulpotomy agent.

RESULTS

The data were analyzed using the Kruskal‒Wallis, Fisher's exact, Spearman's, and Mann‒Whitney tests. The four groups were not significantly different regarding the severity of inflammation (P = 0.53), extent of inflammation (P = 0.72), necrosis (P = 0.361), severity of edema (P = 0.52), extent of edema (P = 0.06), or connective tissue formation (P = 0.064). A significant correlation was noted between the severity and extent of inflammation (r = 0.954, P < 0.001). The four groups were significantly different regarding the frequency of bone formation (P = 0.012), extent of connective tissue formation (P = 0.047), severity of congestion (P = 0.02), and extent of congestion (P = 0.01). No bone formation was noted in the gutta-percha group. The type of newly formed bone was not significantly different among the three experimental groups (P = 0.320).

CONCLUSION

MCM-48 and MCM-48/HA are bioactive nanomaterials that may serve as alternatives for pulpotomy of primary teeth due to their ability to induce hard tissue formation. The MCM-48 and MCM-48/HA mesoporous silica nanomaterials have the potential to induce osteogenesis and tertiary (reparative) dentin formation.