I got my filling in two years ago and when i floss and use plackers they always break. i also notice when i floss the string that has a tiny piece of my filling smell what cause this to happen?

The filling may be rough, it may have an overhang, or there may be recurrent decay at the margin. This needs to be visually inspected by your dentist, with a possible radiograph to determine the cause and necessary treatment.

2 years is too long to go b between Dental appointments. Fillings should be smooth. If there is an odor it may be due to decay (infection) but more probably from diseased gums (infection) from not cleaning between teeth. Please see your Dentist for an evaluation and appropriate treatment.