There are a number of options to improve your smile
Bleaching is a very cost effective way of whitening your smile with minimum intervention. Custom trays are made by your dentist and you then take the trays home with some tubes of bleaching solution (either hydrogen peroxide or carbamide peroxide). You then place the bleaching solution into the trays and wear them for one hour per day. There are also overnight options. Typically you will do this everyday for 1-3 weeks depending on how white you want your teeth. There are other power/laser bleaching options but the overnight/1 hour method has been shown to provide better long term colour change.
Bleaching will not change the the colour of crowns or fillings and occasionally a tooth may be difficult to whiten due to intrinsic staining (the inside of the tooth is discoloured). The teeth may also become temporarily sensitive during the bleaching process. Consult your dentist to see if bleaching is possible for you.
As the name implies, veneers are a thin layer of either composite or porcelain placed over the surface of your front teeth to disguise any discolouration or irregularities.
Porcelain veneers look better, do not stain easily, and are stronger than composite. They take 2 weeks to be made in the laboratory, require tooth removal and are more expensive than composite.
Composite veneers or bonding are a great way of disguising discolouration and reshaping teeth often without the need for removal of tooth structure (conservative). They are not as strong as porcelain and tend to stain over time. Repairs are inexpensive and easy to do.
It is possible to easily replace amalgam fillings with white composite fillings (small to medium fillings) or porcelain (large). It is a great way of getting rid of the grey appearance and possible toxicity.