Dark, shiny “metal” tooth filling therapy has long been used by dentists as a way of halting tooth decay. Often referred to as amalgam filling therapy, this process removes part of the tooth affected by decay, and then fills the area with a semi-soft metal. While usually successful (at least when initially administered), this solution focused solely on short-term dental functionally with little regard to aesthetics or the “wear effects” that are often experienced over time as metal fillings “compress.”
Over the past couple decades, advancements in composite tooth restoration have made metal fillings much less common—and I think for good reason. In my opinion, composite tooth restoration provides aesthetic, structural, and dental health advantages that amalgam fillings just can’t match.
So what are the most common reasons patients cite when they come to me asking about metal filling replacement? Following are the top 5 reasons I hear most, followed by my thoughts regarding each reason:
#1 “I am concerned my amalgam fillings contain mercury and are not safe.”
This is probably the #1 concern I hear from patients requesting filling replacement. In most cases amalgam fillings are a blended metal product made of copper, tin, silver and mercury, which is a toxic metal. Most amalgam fillings are 50% mercury by weight, and some people speculate that the fillings can emit mercury vapors (possibly at dangerous levels) over time. Although there has been no medical research published to confirm this, patients aware of the health risks associated with mercury exposure prefer to have these restorations removed as a precautionary measure. Because mine has always been a conservative, “better-safe-than-sorry” approach, I have never contested this reasoning.
#2 “Metal fillings are ugly and detract from my smile”
On this point there can be no debate. Metal fillings in the back teeth darken a smile by absorbing rather than reflecting light. Metal fillings in frontal teeth that show when you smile are immediately distracting — often conveying a message of poor dental health and hygiene. Patients with this condition tell me that they often try to minimize their smile and laugh, because they became aware that their metal fillings had become a “focal point” of their smile. These same patients-once fillings were replaced—reported they now find themselves laughing and smiling a LOT more!
#3 “The teeth with the metal fillings sometimes hurt.”
Amalgam fillings are a “soft metal,” and over time can shift in shape from pressure and wear. This can cause stresses that result is gaps between tooth and filling. It can also lead to cracks in the tooth. Left untreated, these cracks and gaps can trap cavity-causing bacteria, leading to painful tooth decay. Pain in a filled tooth when eating certain foods (especially foods that are sweet or acidic) is usually an indicator that the metal filling has failed. In these cases, swift action and a new, composite filling to halt and correct the damage is almost always recommended.
4. “My teeth with silver fillings are beginning to break”
Because amalgam fillings remain a soft metal, they transfer biting and chewing pressure downward and out the sides of the tooth. This is especially true because of the way a tooth is typically drilled out to accept a metal filling. Usually, the cavity hole is made wider as it gets deeper (like a pyramid) so that the filling (when hardened) will be “mechanically” locked into position.
As your tooth surface naturally wears over time, the pliable metal fillings are compacted further, often resulting in an increase of outward pressure that eventually begins fracturing off pieces of the tooth crown. When this happens, a large portion of the filling is exposed, and chewing on that side becomes uncomfortable to nearly impossible. In these cases, replacing the filling with a composite filling or composite crown restoration is, in my opinion, the best solution.
#5. “I fear my metal fillings will make health issues harder to diagnose.”
Metal fillings can absolutely make it more difficult for you and your dentist to spot tooth decay. This is true at both the visual assessment and X-ray stages of a check-up. Because discoloration of teeth and gums are a prominent indicator of dental problems, having a dark colored metal embedded in the teeth can sometimes distort those visual indicators — masking the fact that a tooth or gum may require swift treatment.
Considering that published medical research supports the safety and overall effectiveness of amalgam fillings, some dentists advise against removing silver fillings unless they are cracked, chipped, display poor margins, or indicate signs of decay.
At Advanced Cosmetic Dentistry, we believe that the visual and health-related advantages of composite filling replacement creates a pretty sound case for having older, questionable metal fillings replaced— regardless of current symptoms. Every composite restoration patient I have treated tells me “I am so thrilled with the results, and wish I did this years earlier.” For me, patient satisfaction, comfort, and peace-of-mind is a decision-making priority.