A dental filling is a restorative material placed into a tooth after the decayed portion has been removed. Its purpose is to seal the tooth, restore its function and shape, and prevent further infection. While fillings are designed to be durable, they are not permanent, and they can definitively fall out. A lost filling leaves the tooth vulnerable to damage, increased sensitivity, and rapid decay, requiring immediate attention.
Why Dental Fillings Become Loose or Fail
The most common reason for a filling to fail is recurrent decay, which is a new bacterial infection that develops along the margins of the existing restoration. This decay undermines the supporting tooth structure, creating a microscopic gap where bacteria and food debris can enter. Once the underlying enamel and dentin are eroded, the filling loses its stable foundation and can become loose or detach entirely.
Significant mechanical force can also cause failure, especially in patients who experience bruxism (teeth grinding and clenching). This chronic stress puts immense pressure on the filling material and the surrounding tooth, leading to fractures in the filling or the supporting enamel. Also, the constant cycle of thermal expansion and contraction from consuming very hot and very cold foods can strain the bond between the tooth and the filling over time.
In some cases, failure relates to the initial placement technique, particularly with composite fillings that require a strong chemical bond. If moisture contamination occurs during the bonding process, the adhesive strength is compromised from the start, leading to premature failure. Lifestyle factors such as smoking and regular alcohol consumption can also accelerate the breakdown of fillings due to chemical changes in the oral environment.
Lifespan and Material Differences
The expected duration of a dental filling depends on the material used, the location in the mouth, and the size of the restoration.
Amalgam fillings, often called silver fillings, are composed of a mix of metals and are known for their exceptional durability. They are typically placed in back teeth where chewing forces are highest, often lasting between 10 and 15 years, with some lasting up to two decades.
Composite resin fillings are the tooth-colored option, made from a blend of acrylic resin and fine glass particles, favored for aesthetics. While they bond chemically, they are generally less wear-resistant than amalgam, and their median survival time is often estimated to be shorter, sometimes ranging from four to eight years. They remain more susceptible to staining and chipping than their metal counterparts.
Gold restorations, often placed as inlays or onlays, represent the highest standard of longevity and resistance to corrosion, frequently lasting well over 15 years. However, the high cost and the two-appointment process make them a less common choice. Conversely, glass ionomer cement is a weaker, temporary option used for small restorations or for children. It releases fluoride to help prevent further decay, though it may last fewer than five years.
Immediate Steps If a Filling Falls Out
If a filling falls out, contact a dental office immediately to schedule an emergency appointment, even without pain. The exposed area is vulnerable to sensitivity, further decay, and potential fracture. If the missing filling was large, the remaining tooth structure may be weakened and at risk of breaking.
To manage any discomfort, over-the-counter pain relievers such as acetaminophen or ibuprofen can be taken following the package directions. Rinsing the mouth gently with warm salt water helps to clean the area and reduce inflammation. This rinse is beneficial for keeping the newly exposed area free from food debris and bacteria until professional treatment can be provided.
Until the dental appointment, protect the exposed cavity to minimize sensitivity and prevent fracture. A temporary barrier can be created using dental wax, available at most pharmacies, or a small piece of sugar-free chewing gum carefully pressed into the space. Avoid chewing on the side with the lost filling, and abstain from foods that are excessively hard, sticky, or at extreme temperatures, as these can cause further irritation or damage.