# Enamel decussation pattern originates from directional sliding of ameloblasts

## TL;DR

This study reveals how enamel's complex structure forms through the movement of cells called ameloblasts in rodent teeth.

## Contribution

The paper experimentally demonstrates that directional sliding of ameloblasts generates enamel decussation patterns.

## Key findings

- Enamel micropatterning arises from directional epithelial sliding of ameloblasts.
- Cell cluster segregation and interweaving underlie decussation pattern formation.
- A new model of enamel decussation is introduced and experimentally validated.

## Abstract

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.