Linea alba is not pathological lesion. It will not cause any harm.

Linea Alba, is a white line on the inside of the cheek that is caused by function , it is seen on both sides extending from the inner  corner of the lip till the back. It does not cause any problems and is considered normal. Since you mentioned changing your teeth, I assume what you had was a more severe form than linea Alba, if you had any problems before and those problems are solved within 2 weeks of the work done on your teeth, then don't worry about the white line, Giving more specific advise without seeing the condition and more information is not possible, So if your original symptom is not reduced or relived go back to the dentist.