How Long Do White Fillings Last and Why They Fail

White fillings, made from composite resin, routinely survive more than five years with over 90 percent still intact, and many last well beyond a decade. One long-running clinical study tracking composite fillings in back teeth over 17 years found a median survival time of 16 years in a general dental practice setting, though failures accelerated sharply after the 10-year mark. When white fillings do fail, the two dominant reasons are new decay forming around the filling’s edges and the filling itself cracking or chipping. Understanding what drives those failures can help you make better choices about your dental care and know when a filling genuinely needs attention.

What the Clinical Evidence Says About Lifespan

Survival rates for white fillings depend heavily on where in the mouth they sit and how large the cavity was. A 2025 umbrella review of systematic reviews found that conventional composites demonstrated greater than 90 percent five-year survival, particularly when multi-step adhesive systems were used. Bulk-fill resins, a newer category designed for faster placement, showed similar short-to-medium-term outcomes with failure rates under 7 percent, though long-term data remain limited.¹ Those numbers are reassuring for the first several years, but the longer story is more complicated.

A German health technology assessment that pooled data from multiple longitudinal studies reported median survival times for composites ranging from about 8 to 44 years under carefully controlled conditions at dental schools, where technique and patient selection tend to be ideal. In everyday private practice the picture is less rosy. One 17-year study found that while only about 5 percent of posterior composites had failed at the 10-year mark, the failure rate jumped to 40 percent by year 15 and 72 percent by year 17.² That steep late-stage curve suggests that composite fillings do not simply wear out gradually. Instead, they hold up reasonably well for a while and then begin failing in clusters, often because the bond to the tooth deteriorates or the surrounding tooth structure weakens.

Filling size is one of the strongest predictors of how long a composite lasts. A clinical evaluation following posterior composites for 17 years found that the probability of failure was significantly higher for molars, for two-surface cavities, and for large restorations, while the specific brand of composite material made no measurable difference.³ In plain terms, a small filling on a premolar has a much better prognosis than a large filling bridging two surfaces of a molar.

How White Fillings Compare to Silver Ones

Silver amalgam fillings have been around for over 150 years, and their track record is genuinely longer than that of composites. A systematic review comparing the two materials in posterior permanent teeth concluded that amalgam restorations have superior overall longevity. The interesting wrinkle is that they fail for different reasons: composites are more prone to secondary caries at their margins, while amalgam fillings more often fail by fracture.⁴ A separate meta-analysis reached a similar conclusion, finding that composites still show less longevity and more secondary caries than amalgam in posterior teeth.⁵

That said, the gap between the two has been narrowing as composite materials and bonding techniques improve. Amalgam also carries its own drawbacks: it requires more tooth removal during preparation, it contains mercury (which, while considered safe at the levels present in fillings by most regulatory bodies, remains a concern for some patients), and it is conspicuously silver in a world that increasingly values tooth-colored restorations. For front teeth, the comparison is moot since composites are the standard. The debate is really about back teeth, and for many patients the aesthetic and conservation-of-tooth-structure advantages of composites outweigh the modest longevity difference.

The Two Main Reasons White Fillings Fail

Research consistently identifies two culprits responsible for the vast majority of composite filling failures: secondary caries and fracture. A long-term clinical study described these as the dominant failure modes, noting that secondary caries is linked to the individual patient’s caries risk while fracture relates to factors like the material used, whether a lining was placed, and habits like teeth grinding.⁶

Secondary caries means new decay forming at the junction between the filling and the tooth. Composite resin bonds to enamel and dentin through an adhesive layer, and over time that bond can degrade, creating microscopic gaps. Bacteria colonize those gaps, and decay begins underneath or along the margins of the filling. One microbiological study examining the biofilm around both composite and amalgam fillings found that the bacterial composition of secondary caries was similar regardless of the filling material; the difference is that composites seem to develop these marginal gaps more readily.⁷

Fracture is the other big failure mode. Composite resin is strong but not as forgiving under heavy biting forces as metal. A retrospective study of composite restorations on front teeth found that chipping or fracture of the restoration was most common in the first year after placement, suggesting that some early fractures reflect technique or bite-adjustment issues rather than long-term material fatigue. That same study also noted that different composite formulations had different weak points: nanofill composites were more prone to color mismatch, while microhybrid composites fractured more often.⁸

What Happens to the Bond Over Time

The adhesive interface between composite and tooth is where much of the action happens. When a dentist places a white filling, they treat the tooth surface with an acid etchant and then apply an adhesive that infiltrates the etched enamel and dentin, creating what is called a hybrid layer. This layer is the filling’s anchor, and its gradual breakdown is a major driver of long-term failure.

The hybrid layer degrades through a combination of water infiltration and enzymatic attack. Water seeps into the resin matrix over months and years, causing hydrolysis of the resin itself. At the same time, enzymes naturally present in your own dentin, particularly a group of enzymes with collagenolytic activity, begin breaking down the collagen fibers that the adhesive had infiltrated.⁹ Essentially, the bond is being attacked from both directions: the resin component dissolves and the tooth-side collagen gets chewed up by the body’s own enzymes.¹⁰

Researchers have been working on strategies to slow this degradation, including adding enzyme inhibitors and collagen cross-linking agents to adhesive formulations. These approaches show promise in laboratory studies but are still making their way into everyday clinical products. For now, the practical takeaway is that the bond between a composite filling and your tooth is not permanent; it weakens over time, which is why even a filling that looks fine on the surface can eventually develop problems underneath.

Another inherent material limitation is polymerization shrinkage. When composite resin hardens under the curing light, it shrinks slightly in volume. That shrinkage can pull the filling away from the cavity walls, creating stress at the margins and sometimes producing the very gaps that eventually let bacteria in.¹¹ Dentists manage this by placing the composite in thin layers and curing each one individually, but it cannot be completely eliminated.

Patient Factors That Shorten Filling Life

Not everyone’s fillings last the same amount of time, and the biggest variable is your own mouth environment. A systematic review and meta-analysis of posterior composite longevity found that people classified as high caries risk had a dramatically higher chance of filling failure, and that fillings covering more tooth surfaces also failed sooner.¹² Another analysis put numbers on the caries-risk effect: compared with low-risk patients, high-risk individuals had a hazard ratio for composite failure ranging from roughly 2.5 to 4.4, meaning their fillings failed at two and a half to four and a half times the rate.¹³

If you tend to get new cavities frequently, your existing fillings are also at elevated risk. This makes intuitive sense: the same oral environment that causes decay in untreated teeth will attack the vulnerable margins of fillings. Improving oral hygiene, reducing sugar intake, and using fluoride rinses can all help protect both natural tooth structure and the edges of existing restorations.

Bruxism, or habitual teeth grinding and clenching, is the other major patient-side risk factor. A case-control study examining composite fillings in root-canal-treated back teeth found that bruxism significantly worsened outcomes across functional, aesthetic, and biological measures. In people who grind their teeth, even small and medium-sized fillings failed more often, primarily from wear, followed by color changes, surface roughness, new decay, and fracture of the tooth itself.¹⁴ If you grind your teeth, a night guard is one of the best investments you can make in the longevity of your dental work.

How Technique and Curing Affect Results

A white filling is only as good as the process that placed it. A study in primary teeth found that several technique-related factors, including the operator, use of a rubber dam, and the type of adhesive, all significantly affected how long the filling lasted.¹⁵ The dentist’s skill and attention to protocol matter at least as much as the brand of composite they choose.

Moisture control during placement is a perennial concern. Composite adhesives are sensitive to contamination by saliva or blood, and conventional wisdom holds that a rubber dam, the sheet of latex or silicone that isolates the tooth, is the gold standard. A Cochrane review found low-certainty evidence that rubber dam isolation may roughly double the odds of a composite filling surviving at six months compared with cotton roll isolation.¹⁶ However, a clinical trial specifically testing this in primary molars found no difference between rubber dam and cotton rolls over two years.¹⁷ The honest takeaway is that moisture control matters, but the specific method may matter less than how carefully it is executed.

Light curing is another underappreciated variable. The composite resin hardens when exposed to a blue light that triggers a chemical reaction converting soft monomer into hard polymer. If the light intensity is too low or the exposure time too short, the bottom of the filling may not fully harden.¹⁸ Undercured composite is weaker, more prone to wear, and may leach more unreacted chemicals. The distance of the light tip from the filling surface also matters; even a few millimeters of extra distance can significantly reduce the energy reaching the deeper layers.¹⁹ You cannot control this as a patient, but it is worth knowing that a rushed or sloppy curing step can undermine an otherwise well-placed filling.

Bulk-Fill Composites and Newer Formulations

One of the more practical innovations in recent years is bulk-fill composite, which can be placed in thicker layers rather than the traditional thin increments. This saves chair time and potentially reduces the number of interfaces between layers where problems could develop. The clinical question is whether that convenience comes at a cost to durability.

So far, the answer appears to be no. A 2025 systematic review and meta-analysis found no statistically significant difference in failure rates between bulk-fill and conventional incrementally placed composites, and subgroup analyses based on follow-up duration showed no divergence over time.²⁰ An earlier systematic review covering follow-up intervals from six months to 10 years reached the same conclusion.²¹ A third meta-analysis also reported no significant differences in failure rates between the two approaches.²² If your dentist uses a bulk-fill composite, the evidence suggests you are not sacrificing longevity for convenience.

Not all alternative materials fare as well. Glass ionomer cement, another tooth-colored material sometimes used in fillings, has a considerably worse track record for durability. An umbrella review noted that while glass ionomers perform acceptably in certain limited situations, their medium-to-long-term performance remains questionable and is highly dependent on technique and cavity type.²³ An older study comparing glass ionomer to amalgam in children’s teeth found that two-surface glass ionomer fillings had a median survival of only about 34 months because of frequent fractures.²⁴ Glass ionomers do release fluoride, which may offer some protection against decay in adjacent teeth, but they simply cannot withstand chewing forces the way composites can.

Repair Versus Replacement

When a white filling develops a defect, the reflexive response has traditionally been to drill it out and replace it entirely. But a growing body of evidence supports a more conservative approach: repairing the damaged area while leaving the intact portions alone. A systematic review found that repair, refurbishment, and sealing techniques produced results comparable to full replacement for defective direct restorations, with high-quality evidence supporting repair and refurbishment.²⁵ The advantage of repair is that it preserves healthy tooth structure, which becomes increasingly precious with each replacement cycle. Every time a filling is fully replaced, the cavity gets a little bigger, and the tooth gets a little weaker.

The economics support this approach as well. A cost-effectiveness analysis found that repairing a composite filling yielded slightly greater longevity than full replacement at a comparable cost, and under most realistic pricing scenarios, repair was the cost-effective choice.²⁶ A separate long-term analysis showed that the annual treatment costs of repair and replacement were not significantly different, but repair avoided the loss of additional tooth structure.²⁷ If your dentist suggests repairing a filling rather than redoing it, that is not cutting corners; it is a legitimate, evidence-supported strategy.

When Your Dentist Says a Filling Needs Replacing

One underappreciated issue is how dentists decide a filling has failed. Marginal staining, where the edge of the filling turns brown or gray, and marginal ditching, where a visible groove forms at the junction between filling and tooth, are commonly flagged as signs of trouble. But a clinical study specifically testing whether these signs predicted actual decay underneath found that they did not. The only reliable indicator of secondary caries in that study was a frankly visible cavity at the margin.²⁸

This matters because premature replacement of fillings that are stained but still functional wastes both money and tooth structure. Not every cosmetic imperfection is a structural failure. If a dentist recommends replacing a filling based primarily on staining or a minor surface defect, it is reasonable to ask whether there is evidence of actual decay, whether a repair could address the problem, and what the consequences of simply monitoring it would be. Some fillings that look imperfect at a check-up have years of useful life left.

Post-Operative Sensitivity

Many people experience sensitivity to hot, cold, or biting pressure after a composite filling is placed. This does not necessarily mean the filling has failed. Post-operative sensitivity can arise from several causes: temporary inflammation of the pulp triggered by the drilling itself, incomplete sealing of exposed dentin that creates gaps where fluid movement stimulates the nerve, or a filling that sits slightly high and absorbs excessive force when you bite down.²⁹

Mild sensitivity that fades over a few weeks is normal and usually resolves on its own as the pulp settles down. Persistent or worsening sensitivity, particularly to biting, warrants a return visit. The bite may need adjusting, or the bond may have a gap that needs sealing. In most cases, these are fixable problems that do not require starting over from scratch.

BPA and Chemical Leaching

Composite resins are based on a chemistry that involves bisphenol A (BPA), an endocrine-disrupting chemical that has attracted considerable public concern. BPA is a building block used to make Bis-GMA, the main resin monomer in most composites. Laboratory studies have confirmed that BPA and related compounds do leach from composite materials and dental sealants, in some cases at concentrations where biological effects have been observed in experimental models.³⁰ One clinical study measuring BPA levels in men after composite fillings were placed found detectable increases in serum BPA, with higher levels in blood than in saliva.³¹

The clinical significance of this exposure remains debated. Most of the BPA release occurs in the first few hours to days after placement, then drops substantially. The amounts are orders of magnitude below the daily intake limits set by regulatory agencies for dietary BPA exposure. Some newer composite formulations use alternative monomers that avoid Bis-GMA entirely. If this is a concern for you, ask your dentist whether BPA-free composite options are available, though at the moment the consensus in mainstream dentistry is that the levels released from fillings do not pose a meaningful health risk for most people.

Why Direct Fillings Beat Indirect Restorations on Cost

When a filling fails and the cavity is large, the conversation sometimes shifts toward an indirect restoration: an inlay, onlay, or crown made in a lab and cemented in place. These are more durable in extreme situations but come at substantially higher cost. A 15-year study comparing direct fillings with various indirect restorations found that direct composite placements were more cost-effective at every time interval measured.³² For large posterior cavities, full gold crowns were the most cost-effective indirect option, and ceramometal crowns led for front teeth, but both still cost more per year of service than a well-placed direct composite. This does not mean indirect restorations are never justified. For heavily broken-down teeth, a crown may be the only viable option. But for the average cavity, a direct composite filling remains the most economical choice, even accounting for the occasional repair or replacement down the line.