Quantitative characterization of indentation initiated crack growth in bovine enamel

Abstract In this in vitro study, indentation cracks in orthogonal directions and different areas on bovine enamel occlusal surface were analyzed by quantitative characterization of crack number, length and displacement, aiming to reveal the correlation between the microstructure and crack growth beh...

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Main Authors: Heng Xiao, Lei Lei, Jing Zheng, Zhongrong Zhou
Format: Article
Language:English
Published: Nature Portfolio 2025-03-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-94536-7
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author Heng Xiao
Lei Lei
Jing Zheng
Zhongrong Zhou
author_facet Heng Xiao
Lei Lei
Jing Zheng
Zhongrong Zhou
author_sort Heng Xiao
collection DOAJ
description Abstract In this in vitro study, indentation cracks in orthogonal directions and different areas on bovine enamel occlusal surface were analyzed by quantitative characterization of crack number, length and displacement, aiming to reveal the correlation between the microstructure and crack growth behavior of bovine enamel. Results showed that the cracks induced by indenting on the enamel occlusal surface tend to initiate at the rod/inter-rod boundaries. The rod/inter-rod hydroxyapatite (HAP) nanofibers and associated decussation cause a preferential extension of the cracks along the rod/inter-rod interface by inducing crack deflection, bifurcation, and bridging. In addition, the inter-rod nano-structure, consisting of orderly assembled HAP nanofibers, leads to an additional toughening mechanism of zig-zag cracking to hinder crack growth within the narrow inter-rod region. In summary, the unique microstructural architecture of bovine enamel, especially the decussation within rod/inter-rod nanofibers, plays an important role in functionally guiding cracks on bovine enamel occlusal surface to grow along the interface between rod and inter-rod rather than across the inter-rod enamel. The anisotropic crack growth behavior helps prevent bovine enamel from substantial fracture and chipping induced wear. These findings extend the understanding of the toughening mechanisms of mammalian enamel.
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spelling doaj-art-6845216e1b294cb9a0cd47a0b1c2c0162025-08-20T02:41:31ZengNature PortfolioScientific Reports2045-23222025-03-0115111010.1038/s41598-025-94536-7Quantitative characterization of indentation initiated crack growth in bovine enamelHeng Xiao0Lei Lei1Jing Zheng2Zhongrong Zhou3School of Mechanical Engineering, Xihua UniversityTribology Research Institute, Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong UniversityTribology Research Institute, Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong UniversityTribology Research Institute, Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong UniversityAbstract In this in vitro study, indentation cracks in orthogonal directions and different areas on bovine enamel occlusal surface were analyzed by quantitative characterization of crack number, length and displacement, aiming to reveal the correlation between the microstructure and crack growth behavior of bovine enamel. Results showed that the cracks induced by indenting on the enamel occlusal surface tend to initiate at the rod/inter-rod boundaries. The rod/inter-rod hydroxyapatite (HAP) nanofibers and associated decussation cause a preferential extension of the cracks along the rod/inter-rod interface by inducing crack deflection, bifurcation, and bridging. In addition, the inter-rod nano-structure, consisting of orderly assembled HAP nanofibers, leads to an additional toughening mechanism of zig-zag cracking to hinder crack growth within the narrow inter-rod region. In summary, the unique microstructural architecture of bovine enamel, especially the decussation within rod/inter-rod nanofibers, plays an important role in functionally guiding cracks on bovine enamel occlusal surface to grow along the interface between rod and inter-rod rather than across the inter-rod enamel. The anisotropic crack growth behavior helps prevent bovine enamel from substantial fracture and chipping induced wear. These findings extend the understanding of the toughening mechanisms of mammalian enamel.https://doi.org/10.1038/s41598-025-94536-7Bovine enamelIndentation crackCrack growthAnisotropyNanofiber
spellingShingle Heng Xiao
Lei Lei
Jing Zheng
Zhongrong Zhou
Quantitative characterization of indentation initiated crack growth in bovine enamel
Scientific Reports
Bovine enamel
Indentation crack
Crack growth
Anisotropy
Nanofiber
title Quantitative characterization of indentation initiated crack growth in bovine enamel
title_full Quantitative characterization of indentation initiated crack growth in bovine enamel
title_fullStr Quantitative characterization of indentation initiated crack growth in bovine enamel
title_full_unstemmed Quantitative characterization of indentation initiated crack growth in bovine enamel
title_short Quantitative characterization of indentation initiated crack growth in bovine enamel
title_sort quantitative characterization of indentation initiated crack growth in bovine enamel
topic Bovine enamel
Indentation crack
Crack growth
Anisotropy
Nanofiber
url https://doi.org/10.1038/s41598-025-94536-7
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AT leilei quantitativecharacterizationofindentationinitiatedcrackgrowthinbovineenamel
AT jingzheng quantitativecharacterizationofindentationinitiatedcrackgrowthinbovineenamel
AT zhongrongzhou quantitativecharacterizationofindentationinitiatedcrackgrowthinbovineenamel