It has recently been discovered that metal fillings react the same way that metal responds outside of a tooth. When exposed to cold or heated items, like ice cream or hot cocoa, metal tooth fillings will contract or expand. This shifting is very counterproductive because it actually weakens the teeth the amalgam filling is intended to strengthen. Over time, all of the contraction and expansion of the metal filling can lead to cracks in the tooth structure.
In addition, as the tooth fillings expand and contract tiny openings form that allows bacteria to enter and cause more damage to the tooth. Small fractures can also develop in teeth enamel creating spaces for harmful bacteria to get in and cause further decay. It is very common for dentists to discover additional underlying decay after removing metal fillings.
A more conservative way to restore teeth is with dental inlays and onlays. Traditional metal fillings can reduce tooth strength by about 50 percent, while high-quality porcelain inlays and onlays can provide up to 75 percent more protection that can last up to 30 years.
Amalgam is a popular combination of metal filling materials that have been used by dentists for 150 years to treat cavities. Sometimes called silver fillings, or silver amalgam, it typically consists of silver, tin, copper and mercury. Trace amounts of inidium, zinc or palladium may be included in the mix.
Today, white or tooth-colored composite materials are more desirable options for tooth restoration. Amalgam fillings are being used much less often although; the newer, more visually appealing materials are not the best option for all cases. Metal fillings are cheaper and tend to withstand the impact of chewing better.
Like traditional fillings, inlays are placed inside the tips, or cusp, of a tooth. They are custom-made of porcelain that is shaded to perfectly match the color of the surrounding natural teeth. First, your dentist will make a temporary dental inlay, take a mouth impression and ship the model to an outside lab. When the final inlay is completed, it will be returned to your dental clinic where it will be bonded and polished to your tooth by your dentist.
Like inlays, onlays are also constructed of porcelain. But, onlays are larger pieces that extend over one or more of the tooth tips, or cusps. Onlays can sometimes be used instead of a crown to repair a damaged tooth and leave more the structure intact. Onlays are also created in an outside lab and will require a return dental visit. You will be given a temporary onlay to wear until your final onlay is received and bonded in place.