Replacing old fillings.
Replaced when there is a reason, not on principle
The essentials
In short
An old amalgam filling should be replaced when there is a clinical reason: decay at the margin, a fracture in the filling or the tooth around it, an open or leaking edge, or a cusp already cracked under it. Replacing sound, symptom-free amalgams purely for appearance is elective. It is a legitimate choice, but every replacement removes a little more tooth structure, so it should be a decision made knowingly rather than sold as maintenance.
The honest version of this conversation
There are two entirely different reasons to replace an amalgam, and conflating them is how patients end up with more dentistry than they needed.
Clinical necessity. The filling has failed or the tooth around it has. There is decay under the margin, a crack propagating into a cusp, a leaking edge, or a piece of the tooth has already gone. Here, replacement is treatment, and delaying it usually means the eventual repair is bigger.
Appearance. The filling is intact and the tooth is comfortable, and you would rather not see metal when you laugh. That is a perfectly reasonable thing to want. It is also elective, and it costs a small amount of additional tooth structure, because removing a filling never leaves the cavity exactly as it was.
We will always tell you which of those two you are looking at.
What we look for at your exam
- Radiolucency: a dark shadow on the X-ray under or beside the filling
- Margins you can catch an explorer on
- Fracture lines running from the filling into the tooth, particularly under a wide filling
- Cusps that flex or hurt when you bite something specific
- Recurrent sensitivity that does not settle
- Floss shredding between teeth, which usually means a broken contact
What replacement involves
The tooth is numbed and isolated. The old filling is sectioned and lifted out under water spray and high-volume suction rather than ground away. Then the real assessment begins. What is underneath is often different from what the X-ray suggested. Decay is removed, cracks are examined, and Dr. Patel will tell you at that point whether a bonded composite is sound or whether the tooth needs an onlay or crown.
If that changes the plan mid-appointment, we stop and discuss it rather than proceeding on assumption.
What affects the cost
A like-for-like composite replacement is priced as a filling by surface count. If the tooth needs an onlay or crown, that is a different and higher fee with a laboratory component. Insurance generally covers replacement when there is documented decay or fracture and declines it when the reason recorded is cosmetic, so the diagnosis on the claim matters, and we will be straightforward about what it says.
Talk it through first
Nothing here replaces an examination. If you are weighing this up, the useful next step is a conversation. Bring your questions, bring what you have been told elsewhere, and ask what the alternatives cost over ten years rather than this month.
Oak Hills Dentistry is on Louetta Road in Spring, Texas, and also sees patients from The Woodlands and north Houston. Request an appointment or call 281-350-8852.
Written for patients of Oak Hills Dentistry in Spring, Texas. General dental education, not a diagnosis or a treatment plan for any individual. Updated August 2026. This page covers a higher-risk treatment area and is queued for clinical sign-off by Dr. Neal H. Patel before launch.
The practice
Where the work happens.
FAQ
Know before you visit.
Answers to your most common questions.
The prevailing position of major health authorities, including the FDA and the ADA, is that dental amalgam is safe for the general population, while noting that certain groups (including pregnant and nursing women, young children and people with mercury sensitivity) may reasonably prefer alternatives. We will replace amalgams if you want them gone, and we will not tell you your health depends on it.
Visible decay at the edge, a crack line running from the filling into the tooth, an edge you can catch a probe or floss on, sensitivity to biting or cold that keeps returning, food packing between teeth, or a shadow on an X-ray under the filling. Age alone is not an indication. Plenty of thirty-year-old amalgams are still doing their job.
Amalgams placed decades ago are often large, and the tooth around them has been carrying load for years. When the old filling comes out, the remaining walls are frequently thin, cracked or unsupported. Putting a new filling into that leaves the same fracture risk. An onlay or crown holds the tooth together instead.
Composite is shade-matched to the tooth and is essentially invisible on a small to moderate restoration. Very large replacements in back teeth may be better served by a ceramic onlay, which matches well and stands up to chewing forces better than a large composite.
Yes: high-volume suction, water spray, isolation and sectioning the filling rather than pulverizing it, which limits particulate and vapour and keeps debris out of your mouth. This is standard careful technique.
Start your smile journey.
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