White fillings versus silver, which is better, what are the advantages and disadvantages, etc.
Your dentist will be able to advise you on which is better for you, but for now, take a look at the pros and cons of each.

Strength.

White: Since white fillings bond to the tooth, they restore most of the original strength of the tooth.
Silver: Silver weakens the teeth, making them more susceptible to breaking. Since broken teeth are very expensive to restore, composites can save a lot of expense over the long run.

Looks

White: white fillings restore the natural appearance of the tooth.
Silver: Clearly, silver fillings look silver in the mouth, and do not look nearly as nice.

Sensitivity

White: Teeth restored with white fillings are less sensitive to hot and cold, and for a shorter period of time.
Silver: Teeth restored with silver fillings are typically hot and cold sensitive for several weeks, and sometimes months, after.

Toxins

White: White fillings are mercury-free. Mercury in the fillings is viewed by some as being toxic, and can lead to many other health issues.
Silver: Silver fillings contain mercury that can leach into your body systems.

Tooth removal

White: White fillings require less removal of tooth structure. Especially with new cavities, the size of the hole made for the filling can be dramatically smaller with white fillings.
Silver: The amount of tooth removed is much higher than that of fillings done with white composite.
 
Expense

White: White fillings take longer, and require extra skill, and thus are much more expensive.
Silver: Silver fillings are generally less expensive. White composite fillings, if they are done correctly, take about 60% longer, require special expertise and expensive materials, and are more difficult to place, and so they cost considerably more than silver.

Insurance

White: Many dental insurance companies will not pay for white composite fillings.
Silver: Most dental insurance will pay for silver fillings.

Dentist

White: White fillings requires the use of special bonding technology and require extra training that many dentists are uncomfortable with or have not undergone.
Silver: General dentists can place silver without extra training. Thus you have more choice of dentists to see

Ease of placement

White: It can be very difficult to place. The proper placement of a white filling requires that the site for the filling be kept totally isolated from saliva while it is being placed. This can be very uncomfortable especially if the tooth is in the back of the mouth.
Silver:  A silver amalgam filling does not require this strict isolation of the tooth, and thus is much easier to place.

History

White: white fillings have not been around as long, and while they are better technology, for some dentists, not all the kinks have been worked out.
Silver: silver fillings have a long history and are more tried and tested.

As you can see there are pros and cons to both types of fillings, but as a general rule you can bet that white composite fillings take the advantage. They are newer, and have a few drawbacks, but they are better technology, look nicer, and can withstand similar amounts of pressure as the silver fillings can without the drawback of having mercury. So, if you are unsure, go with the white composite fillings.