Are my teeth "too old" for whitening?

No way! The layer of the teeth that absorbs staining is actually the 2nd layer in (the dentin), and the enamel reflects the shade of this. Over time, the enamel can thin & show the discolouring more prominently. When this happens, we can lighten the shade again by teeth whitening. During our process, we want to let the whitening gel sit long enough to let the 2nd layer of the teeth absorb. Our initial visit is about an hour long, but sometimes when these stains have been sitting for a while on the teeth, it may need a follow up visit to continue brightening to get to your desired shade.