Human tooth enamel retains evidence of growth in the form of Retzius lines. The number of daily growth increments between the regularly occurring lines defines their repeat interval, or periodicity. Retzius periodicity is often incorporated into enamel formation times, age‐at‐death reconstructions, or used to provide a basis from which to explore an underlying biorhythm. Biological anthropologists typically assume that RP remains constant within an individual and does not vary along the tooth‐row. Here, we test that assumption.

中文翻译：

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一种不固定的生物节律：人类恒牙中Retzius周期性的变化速度

人牙釉质保留了以Retzius线形式生长的证据。规则出现的线条之间的每日增长增量的数量定义了它们的重复间隔或周期性。Retzius周期性通常被整合到珐琅质形成时间，死亡年龄重建中，或被用来为探索潜在的生物节律提供基础。生物人类学家通常认为个体中的RP保持恒定，并且不会沿齿行变化。在这里，我们测试该假设。