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Published on: April 26, 2024
Final irrigation protocols affect radicular dentin DMP1-CT expression, microhardness, and biochemical composition
Cristina Retana-Lobo1, Tatiana Ramírez-Mora1, Fabian Murillo-Gómez2
1Department of Endodontics, Faculty of Dentistry, LICIFO, University of Costa Rica, SJO, Sabanilla, San José, 11502, Costa Rica.
Objective:
To evaluate the effect of several final irrigation protocols on radicular dentin microhardness, biochemical composition, and DMP1-CT expression.
Materials And Methods:
A total of 140 single-rooted human teeth were prepared with WaveOne Gold files and randomly distributed into 7 groups (n = 20) according to the final irrigation protocol: distilled water (DW); sodium hypochlorite-EDTA (NaOCl-EDTA); EDTA (EDTA); EDTA-NaOCl (EDTA-NaOCl); EDTA-chlorhexidine (EDTA-CHX); passive ultrasonic irrigation (PUI:NaOCl-EDTA); and PUI:NaOCl-EDTA-NaOCl. Dentin microhardness (n = 10) was evaluated in the root canal lumen using Vickers hardness tester. Immunohistochemical analysis (n = 5) was used to evaluate DMP1-CT expression. Dentin ultrastructure and biochemical composition were evaluated by using Raman and energy dispersive X-ray analysis (EDAX) (n = 5) with a scanning electron microscope (SEM). Analysis of variance (ANOVA) and Tukey test were performed (p˂0.05).
Results:
Raman spectra of the organic content and DMP1-CT expression were lower at the lumen canal in EDTA-NaOCl, PUI:NaOCl-EDTA, and PUI:NaOCl-EDTA-NaOCl when compared to control (p < 0.05). EDAX showed reduced values for calcium and phosphorus in EDTA-NaOCl, PUI:NaOCl-EDTA, and PUI:NaOCl-EDTA-NaOCl. SEM microphotography's showed completely cleaned dentin, permeable tubules, and dentin erosion, mainly when PUI was used. NaOCl-EDTA presented significantly higher microhardness values than PUI:NaOCl-EDTA-NaOCl (p < 0.05). PUI:NaOCl-EDTA-NaOCl exhibited the lowest Vickers hardness values of all groups.
Conclusion:
The final irrigation protocols that used a final rinse with NaOCl and PUI showed a detrimental effect on radicular dentin DMP1-CT expression, biochemical composition, and microhardness.
Clinical Relevance:
The adequate irrigation protocol could be advantageous to preserve the radicular dentin ultrastructure, promote adequate adhesion, and sustain favorable conditions for biomineralization and regeneration.
