Dexter is happy that his magic spell is working on you. He wants you to continue to have bad teeth.

Greetings…I am so happy and proud of the fact that you are falling for my traps… You don’t know what
I’m talking about?… I know that lately, you don’t feel like brushing your teeth at night, and it’s all
because of me…. Hahaha, yes, you heard me right! I put a little magic spell to turn you into a bad kid.
Your grades are starting to drop, you no longer taking care of your cleanliness, and you have become
rude – it means my magic spell is working….