Are there any alternative answers historically given as to why the Hagadah (page 8 of this) says to remove the wicked son's teeth, besides the usual gematria answer?
The Rebbe Rashab has a kabbalistic answer to this, in that don't read it as teeth, rather as the letter shin. By removing the Shin from רשע, you leave the רע, and cut off its source in holiness that lets it exist.
The Abarbanel explains that it means he is making himself as a foreigner, so take away his eating of the Korban Pesach - hit his ability to use his teeth.
In the hagadda attributed to the Malbim - just as your teeth are blunted from that which you feed yourself, you put the food in your mouth which blunts your teeth, so too you answer the Rasha from his own message - he said "for you" (and did not include himself), so too you respond to him by saying "for me and not for him"
Why knock out his teeth specifically and not any other punishment? Since he counted himself out and refuses to eat Matzah, Why does he need teeth!?
ואף אתה הקהה את שניו: למה דוקא הקהת השינים ולא עונש אחר אלא לפי שרשע זה הוציא את עצמו מן הכלל ואינו רוצה לאכול מצה אם־כן, שינים למה לו ?