All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is permissible for you to perform two Rak’ahs or do any good act through which you invoke Allaah to make your teeth straight without the need for that device as Allaah is over all things Omnipotent and everything is easy for Him. Allaah Says (what means): {And your Lord says, "Call upon Me; I will respond to you.}[Quran 40:60]
However, the wisdom of Allaah necessitates linking the means with what causes them to happen, and among complete trust and faith in Allaah is that one should take the proper means. It is for this reason that the Prophet ordered us to seek treatment. Usaamah ibn Shareek narrated that the Bedouins asked: “O Prophet of Allaah, shall we not seek treatment?” The Prophet replied: "Yes, O slaves of Allaah, seek treatment as Allaah has not sent down a disease except that he has sent down a cure for it…” [Ahmad, Abu Daawood, At-Tirmithi, and Ibn Maajah]
Therefore, if the doctors see that there is a benefit in using that device, then you should act according to their advice.
However, if you do not want to act according to their advice, then it is up to you because seeking treatment is not an obligation and you are not obliged to use that device.
Allaah Knows best.