Enamel,the inorganic tissue covering the crowns of teeth,is known for its remarkable resilience and hardness.These properties originate from its high proportion of mineralized matrix and complex internal microarchitec...Enamel,the inorganic tissue covering the crowns of teeth,is known for its remarkable resilience and hardness.These properties originate from its high proportion of mineralized matrix and complex internal microarchitecture.On an ultrastructural level,it consists of directionally arranged enamel prisms.Continuously growing rodent incisors are an exemplary case of this phenomenon.Their enamel has a consistent decussation pattern,providing teeth with extremely high resistance and ensuring they remain constantly sharp.While the decussation pattern has been described in detail,mechanisms behind its formation have not been experimentally proven.Here,we show that the highly organized enamel micropattern is generated by directional epithelial sliding of enamel-forming ameloblasts in vivo.Our results detail how enamel micropatterning stems from individual cell cluster segregation and subsequent reciprocal interweaving.Based on this determination,we introduce and experimentally demonstrate a new model of enamel decussation pattern formation.展开更多
The ingenious hierarchical structure of enamel composed of rods and protein produces excellent fracture resistance.However,the fracture resistance mechanism in the inner enamel is unknown.The micromechanical models of...The ingenious hierarchical structure of enamel composed of rods and protein produces excellent fracture resistance.However,the fracture resistance mechanism in the inner enamel is unknown.The micromechanical models of enamel are constructed to numerically analyze the mechanical behaviors of the inner enamel with different decussation angles and different decussation planes.The results show that the manner of crack propagation in the inner enamel,including crack bridging,crack deflection,and crack bifurcation,is determined by both the rod decussation angle and the decussation plane.In the case of the strong decussation plane,the fracture strength and the required energy dissipation with the decussation angles of 15°and 30°are much higher than those without decussation,demonstrating that decussation is an important mechanism in improving the fracture resistance of enamel.The maximum tensile stress of enamel with the decussation angle of 15°is slightly higher than that of enamel with the decussation angle of 30°,illustrating that an optimal decussation angle exists which balances the strength and toughness.The synergetic mechanism of the decussation angle and the decussation plane on the crack propagation provides a new design hint for bionic composites.展开更多
基金supported by the Czech Science Foundation (23-06160S)by the Faculty of Medicine of Masaryk University (MUNI/A/1738/2024)。
文摘Enamel,the inorganic tissue covering the crowns of teeth,is known for its remarkable resilience and hardness.These properties originate from its high proportion of mineralized matrix and complex internal microarchitecture.On an ultrastructural level,it consists of directionally arranged enamel prisms.Continuously growing rodent incisors are an exemplary case of this phenomenon.Their enamel has a consistent decussation pattern,providing teeth with extremely high resistance and ensuring they remain constantly sharp.While the decussation pattern has been described in detail,mechanisms behind its formation have not been experimentally proven.Here,we show that the highly organized enamel micropattern is generated by directional epithelial sliding of enamel-forming ameloblasts in vivo.Our results detail how enamel micropatterning stems from individual cell cluster segregation and subsequent reciprocal interweaving.Based on this determination,we introduce and experimentally demonstrate a new model of enamel decussation pattern formation.
基金Project supported by the National Natural Science Foundation of China(Nos.12072184,12002197,12202257)。
文摘The ingenious hierarchical structure of enamel composed of rods and protein produces excellent fracture resistance.However,the fracture resistance mechanism in the inner enamel is unknown.The micromechanical models of enamel are constructed to numerically analyze the mechanical behaviors of the inner enamel with different decussation angles and different decussation planes.The results show that the manner of crack propagation in the inner enamel,including crack bridging,crack deflection,and crack bifurcation,is determined by both the rod decussation angle and the decussation plane.In the case of the strong decussation plane,the fracture strength and the required energy dissipation with the decussation angles of 15°and 30°are much higher than those without decussation,demonstrating that decussation is an important mechanism in improving the fracture resistance of enamel.The maximum tensile stress of enamel with the decussation angle of 15°is slightly higher than that of enamel with the decussation angle of 30°,illustrating that an optimal decussation angle exists which balances the strength and toughness.The synergetic mechanism of the decussation angle and the decussation plane on the crack propagation provides a new design hint for bionic composites.
