I went for my normal cleaning, and I'm getting married in Sept, so they give you a free whitening kit for home use as a "gift" They looked at my teeth & said my front left is "dead" and it might not whiten. Could this happen within the last 6 months, I go regularly every 6 months, get my xrays 1x yearly. Will the bleaching work? I've read that hypericum can revive dead nerves, will this be effective on a dead tooth? What will I have to do with it?