ג
חָתַךְ מִבְּהֵמָה לֶחִי שֶׁיֵּשׁ בּוֹ שִׁנַּיִם חַדִּים וְשָׁחַט בָּהֶם, שְׁחִיטָתוֹ פְּסוּלָה, מִפְּנֵי שֶׁהֵם כְּמַגָּל. אֲבָל בְּשֵׁן אֶחָד הַקָּבוּעַ בַּלֶּחִי, שׁוֹחֵט בּוֹ לְכַתְּחִלָּה.
Seif 3
If one cuts with a jaw of an animal that has sharp teeth and slaughters with it, his slaughter is invalidated. (because it is like a sickle).
However with one tooth that is affixed to the jaw, if one slaughters (before the fact) it is permissible.