While many believe a filled tooth is immune to further decay, this is incorrect. Teeth with existing fillings can develop new cavities, as the surrounding natural tooth structure remains susceptible. Fillings treat existing decay but do not offer lifelong immunity.
Understanding Decay Around Fillings
New decay can form around or under an existing filling. This often occurs at the margin where the filling meets the tooth structure, or beneath the restoration. Microscopic gaps, wear, or a breakdown in the bond between the filling and tooth allow bacteria and food particles to infiltrate. Filling materials can also degrade, crack, or pull away from the tooth due to daily chewing forces, temperature changes, or natural wear and tear. This degradation creates new pathways for decay.
Factors That Increase Risk
Several factors increase the likelihood of new cavities forming around existing fillings.
Inadequate brushing and flossing allow plaque to build up, especially around filling edges, providing a breeding ground for bacteria. Frequent consumption of sugary or acidic foods and drinks contributes to acid production by bacteria, eroding tooth enamel.
Reduced saliva flow, known as dry mouth, decreases the mouth’s natural ability to neutralize acids and wash away food particles, raising the risk of decay.
The age of fillings also plays a role, as older restorations are more prone to wear, leakage, or fracture. Fillings in hard-to-clean areas, such as between teeth or in deep grooves, can be more vulnerable. Some individuals are naturally more prone to developing cavities due to their susceptibility.
Detecting and Addressing New Cavities
Detecting new cavities around fillings often requires professional dental examination. Dentists use visual inspection, dental instruments, and X-rays to identify areas of concern. X-rays are particularly useful for revealing decay hidden beneath the filling or between teeth.
Patients might notice symptoms such as increased sensitivity to hot, cold, or sweet foods, persistent toothaches, or visible discoloration around the filling. If new decay is found, treatment usually involves removing the old filling and the affected tooth structure. A new, sometimes larger, filling is then placed, or a crown may be necessary for extensive damage.
Preventing Future Decay
Preventing new cavities around existing fillings involves consistent oral hygiene and regular professional care. Brushing twice daily with fluoride toothpaste and flossing once a day helps remove plaque and food particles, especially around filling margins. Fluoride strengthens tooth enamel, making it more resistant to acid attacks.
Limiting sugary and acidic foods and drinks is beneficial, as these contribute to the acidic environment that promotes decay. Regular dental check-ups and professional cleanings are important for early detection of issues and for removing plaque and tartar buildup. Your dentist may also suggest fluoride rinses or professional fluoride treatments. Addressing dry mouth, if present, through various management strategies can also help maintain oral health.