Hi! I Have Had My Wisdom Teeth For About 3

Hi! I have had my wisdom teeth for about 3 years now, I had braces and my dentist extracted my molars to let my wisdom teeth come through. A few weeks ago I took a look in the back of my mouth and noticed 1 of my wisdom teeth is a brownish colour! I got sort of freaked out. None of my other teeth are like this. I don't have any pain or sensitivity or anything like that. Any insight on what it could it be?
Thank you!