The Short Answer
Silver (amalgam) fillings are strong and long-lasting, but they’re about half mercury by weight, need more drilling, and show up as dark spots. Tooth-colored composite fillings are mercury-free and bonded to the tooth, so less healthy tooth has to be removed. We use composite for most cavities. If you already have silver fillings that are in good shape, the FDA doesn’t recommend removing them just because they’re silver.
At Precision Dentistry of Olympia, Dr. Eric Xu uses tooth-colored composite fillings as the first option for treating cavities and for replacing old mercury fillings. Silver fillings were the standard for well over a century, though, and they still do some things well.
Amalgam vs. Composite Fillings at a Glance
| Silver amalgam filling | Composite filling | |
|---|---|---|
| Made of | Mercury mixed with silver, tin, and copper (about 50% mercury by weight) | Tooth-colored resin with fine glass particles |
| How it stays in | Packed into a cavity shaped to lock it in place | Bonded to the tooth with an adhesive |
| Healthy tooth removed | More, to create that locking shape | Less, mostly just the decay |
| Appearance | Silver, darkens over time | Shaded to match your tooth |
| Typical lifespan | Can last 10 to 15 years or more | Can last 10 years or more with good care |
Why We Choose Composite
Less drilling
An amalgam filling has to be held in mechanically, so the cavity is shaped with undercuts that grip it. That means removing healthy tooth along with the decay. Composite is bonded in place, so Dr. Xu can remove the decay and leave more of the tooth alone. That fits our conservative approach to dentistry.
Bonded to the tooth
Because composite bonds to the enamel and dentin around it, it seals the edges of the filling and helps support the remaining tooth, instead of just sitting inside it.
Mercury-free
Composite contains no mercury. For patients who want to avoid it, or who fall into one of the groups the FDA says should avoid amalgam (more on that below), composite is the obvious choice.
It matches your tooth
Composite is shaded to blend in with the tooth around it. Our post on how composite fillings blend with your natural teeth goes into how we match and shape them.
Where Amalgam Still Holds Up
Amalgam’s main strength is durability. Research comparing the two has found that in large fillings on back teeth, amalgam tends to last as long as composite or longer. Composite is also more sensitive to technique: the tooth has to stay completely dry while it’s bonded, which is why careful placement matters so much.
Amalgam does have drawbacks beyond the color. Large silver fillings expand and contract with hot and cold, and over the years that can contribute to cracks in the tooth around them. They can also give the surrounding tooth a gray tint.
Are Silver Fillings Safe?
The FDA considers amalgam safe for most adults, but in 2020 it recommended that higher-risk groups get non-amalgam fillings when possible. That includes:
- People who are pregnant, planning a pregnancy, or nursing
- Young children
- People with existing kidney or neurological problems
- Anyone allergic or sensitive to mercury or the other metals in amalgam
The FDA also does not recommend removing amalgam fillings that are in good condition. Drilling one out removes more healthy tooth and briefly increases mercury vapor exposure.
Should You Replace Your Old Silver Fillings?
It makes sense to replace a silver filling when it’s cracked, leaking, or has decay underneath it, or when the tooth around it has started to crack. If you’re in one of the higher-risk groups above, that’s worth talking through with Dr. Xu too.
A small failing filling can usually be replaced with composite. If the old filling is large and there isn’t much tooth left around it, an inlay or onlay may be the stronger, more conservative repair.
What Our Patients Say
Dr. Xu is an exceptional dentist. I moved to Olympia a few months ago and needed an emergency extraction. He performed the procedure completely painlessly, which immediately gave me confidence in his skill and professionalism…
Dr. Xu is an exceptional dentist. I moved to Olympia a few months ago and needed an emergency extraction. He performed the procedure completely painlessly, which immediately gave me confidence in his skill and professionalism. Afterward, he created a comprehensive treatment plan, and I’ve since returned three more times for fillings. Every visit has been an outstanding experience. I especially appreciated that he used two different filling materials—a medicated base that continues to help protect and heal the tooth, followed by a durable outer composite filling. Taking the extra time to do what’s best for the long-term health of the tooth really impressed me…
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My experience with Dr. Xu and his staff has been extraordinary. Dr. Xu is an excellent dentist and I have been to many. He’s very thorough and clearly explains his procedures in advance…
My experience with Dr. Xu and his staff has been extraordinary. Dr. Xu is an excellent dentist and I have been to many. He’s very thorough and clearly explains his procedures in advance. Everyone in the office is friendly, helpful, and very knowledgeable. I’ve learned more about dentistry from these hygienists than any in my past experience. They know their stuff! I recommend them highly.?
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Both Dr. Xu and his staff are incredibly helpful! He explained everything he did during my dental procedure, and his front desk staff, Danielle, was very helpful about my insurance…
Both Dr. Xu and his staff are incredibly helpful! He explained everything he did during my dental procedure, and his front desk staff, Danielle, was very helpful about my insurance. These people are HERE for their patients! As I face a fair amount of dental work, I’ll definitely be a return patient.
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Frequently Asked Questions
Can composite be used on back teeth?
Yes. We use composite on front and back teeth, including the chewing surfaces of molars.
Do composite fillings stain?
The surface can pick up some stain over the years, especially from coffee, tea, red wine, or tobacco. Regular cleanings and polishing help, and a filling that has darkened noticeably can be replaced.
How much does a filling cost without insurance?
It depends on the size of the filling and the tooth. Call us for current pricing. Our membership program takes 10% off fillings, and patients paying out of pocket without insurance or a membership plan get 5% off.
Have an Old Silver Filling You’re Unsure About?
Dr. Xu can check it with an intraoral camera and X-rays and let you know whether it’s still sound or should be replaced. Call (360) 995-0025 or request an appointment. We’re open Monday and Wednesday through Friday, 8 a.m. to 5 p.m., at 2728 Westmoor Court SW, Suite D, Olympia, WA 98502.