Reference for Kiddushin 48:1

שן דחלב כתב רחמנא עין ואי כתב רחמנא עין ה"א מה עין שנברא עמו אף כל שנברא עמו אבל שן לא צריכא

to a milk tooth;<span class="x" onmousemove="('comment',' Which does return; e.g., if the slave was a minor.');">¹</span> therefore the All-Merciful wrote 'eye'.<span class="x" onmousemove="('comment',' Just as an eye does not return, so must the tooth also be one which does not return.');">²</span> And had the All-Merciful written 'eye', I would have thought,just as the eye is created with him, so must all [for whose loss he is emancipated] be created with him [i.e., at birth], but not a tooth.

Jastrow