Melatonin-doped polymeric nanoparticles induce high crystalline apatite formation in root dentin. Issue 11 (November 2021)

• Record Type: Journal Article
• Authors: Toledano-Osorio, Manuel; Aguilera, Fátima S.; Muñoz-Soto, Esther; Osorio, Estrella; Toledano, Manuel; Escames, Germaine; Medina-Castillo, Antonio L.; Osorio, María T.; López-López, Modesto T.; Vallecillo-Rivas, Marta; Osorio, Raquel
• Is Part Of: Dental materials. Volume 37:Issue 11(2021)
• Page Start: 1698
• Page End: 1713
• Publication Date: 2021-11
• Subjects: Apatite -- Dentin -- Hardness -- Melatonin -- Polymeric nanoparticles -- Remineralization -- Transmission electron microscopy -- X-ray diffraction; Dentistry -- Periodicals; Dental materials -- Periodicals; 617.695
• DOI: 10.1016/j.dental.2021.09.001
• Languages: English
• ISSNs: 0109-5641

Abstract

Graphical abstract: Highlights: ML-doped polymeric nanoparticles avoided degradation of root dentin interface. Undoped NPs provoked peak broadening and poor crystallinity with decreased hardness. ML-NPs inducted preferred and randomly oriented crystallites influencing hardness. Abstract: Objective: To investigate the effect of novel polymeric nanoparticles (NPs) doped with melatonin (ML) on nano-hardness, crystallinity and ultrastructure of the formed hydroxyapatite after endodontic treatment. Methods: Undoped-NPs and ML-doped NPs (ML-NPs) were tested at radicular dentin, after 24 h and 6 m. A control group without NPs was included. Radicular cervical and apical dentin surfaces were studied by nano-hardness measurements, X-ray diffraction and transmission electron microscopy. Mean and standard deviation were analyzed by ANOVA and Student-Newman-Keuls multiple comparisons (p < 0.05). Results: Cervical dentin treated with undoped NPs maintained its nano-hardness values after 6 m of storage being [24 h: 0.29 (0.01); 6 m: 0.30 (0.02) GPa], but it decreased at apical dentin [24 h: 0.36 (0.01); 6 m: 0.28 (0.02) GPa]. When ML-NPs were used, nano-hardness was similar over time [24h: 0.31 (0.02); 6 m: 0.28 (0.03) GPa], at apical dentin. Root dentin treated with ML-NPs produced, in general, high crystallinity of new minerals and thicker crystals than those produced in the rest of the groups. After 6 m, crystals became organized in randomly oriented polyhedral, square polygonal block-like apatite or drop-like apatite polycrystalline lattices when ML-NPs were used. Undoped NPs generated poor crystallinity, with preferred orientation of small crystallite and increased microstrain. Significance: New polycrystalline formations encountered in dentin treated with ML-NPs may produce structural dentin stability and high mechanical performance at the root. The decrease of mechanical properties over time in dentin treated without NPs indicates scarce remineralization potential, dentin demineralization and further potential degradation. The amorphous stage may provide high hydroxyapatite solubility and remineralizing activity.