What is the ruling on filing teeth?

Filing teeth is forbidden if it is for increasing beauty and adornment, and permissible if it is for treatment or removing a defect, such as a tooth being longer than the rest of the teeth. This is based on the hadith of Ibn Mas'ud (may Allah be pleased with him): "Allah has cursed the tatuists and those who get tattoos, and the mutanammisaat (women who pluck hair from their faces), and the mutafallijaat (women who separate their teeth) for the sake of beauty, those who alter the creation of Allah." Al-Nawawi clarifies that "the mutafallijaat for beauty" means altering teeth with a file to make them appear smaller or more beautiful, which is forbidden because it alters the creation of Allah. However, if it is for a need, such as treatment or a defect, then there is no objection.