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.

Buchmann Institute for Molecular Life Sciences Institute of Cell Biology and Neuroscience Goethe University Frankfurt Frankfurt am Main Germany

Department of Histology and Embryology Faculty of Medicine Masaryk University Brno Czech Republic

Department of Neuroimmunology Center for Brain Research Medical University of Vienna Vienna Austria

Department of Physiology and Pharmacology Karolinska Institutet Stockholm Sweden

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