Mark Sayeg, DDS

Your first step would be to get your teeth cleaned and the filling polished. This should remove any topical stain you may have on the tooth. If it does not then the filling may have to be replaced because the filling is leaking and the Gentian Violet got in between the tooth and filling the same way bacteria can.

You first will need to see a dentist to professionally clean your teeth to get all of the topical stains off the teeth. Your dentist may then recommend a professional whitening using custom trays with professional strength whitening solution.

That should give you the white smile you always wanted

before you even consider veneers I might recommend orthodontics to correct your crossbite. Doing veneers would  create an effect of your having only 6 front teeth. Properly done your dentist should be able to mask out the tetracycline stain but would recommend finding a dentist who specialize in cosmetic dentistry. If orthodontics is not an option I would recommend extensive whitening to decrease the gray appearance.

without seeing you in person it is difficult to determine the problem. The first thing I would check is your bite. Having a tooth extracted may have changed the way your teeth hit together putting excessive pressure on those teeth that have become sensitive. 

sorry you are having problems. Bridges are sometimes cemented in with a temporary cement to insure that everything is correct and healed. But after some time the cement may start breaking down and start leaking or become loose allowing bacteria to build up around the margins resulting in the bad odor. The bridges may need to be recemented with a stronger cement. This should solve your problem. By the way your new smile looks great.