I have white spots on my teeth after dental bonding. Why did this happen and can it be fixed?

I had dental bonding done on my top two big teeth about 7 years ago, im 22 now, but ever since that procedure when i breath through my mouth i get white spots on my teeth. I have the white spots on my top 6 teeth and its the bottom half of thr teeth. My first two big teeth(the bonded ones) its the bottom 50% , then the 2 beside that its about the bottom 33% , and its just the tip on my canine teeth. These white spots usually go sway in sbout 3 hours. Why did this happen and can it be fixed?