Advance Parole Question

Is necessary dental work a good enough reason to request AP? I don’t know anybody that has asked permission for that reason (what proof will I need)? I’ve got many fillings that need redone and one of my cousins is a dentist and she’ll do it for free. Also, idk anybody that has done AP for my country (Brasil). Last question, how long does it usually take for it to get approved, and how long can I stay in my home country for? Thanks in advance my people!