How Is It Possible for a Dental Filling to Leak?

In terms of general dentistry, having a cavity filled is about as general as it gets. It's an efficient means of plugging the hole in your tooth while offering a predictable outcome. Of course, this outcome isn't always as predictable as you and your dentist would like. How is it possible for a dental filling to leak? And more importantly, does this pose a risk to your tooth and overall dental health?

Potential Contaminants

You might assume that a leaking filling is when the filling itself leaks outwards, but it's actually the opposite. It's when potential contaminants leak into the tooth around the edges of the filling. The substance leaking into the tooth is primarily saliva, but this saliva can contain contaminants such as bacteria and tiny particles of food. Unfortunately, this can cause problems.

Dentin Tubules

Your teeth are covered in protective dental enamel, and beneath that enamel is dentin, which forms the majority of a tooth's bulk. This dentin contains thousands of tubules, which are microscopic canals leading from the exterior of the dentin into the tooth's pulp chamber, and this is where the tooth's nerve is found. Contaminants in these tubules can irritate (and even infect) the nerve. Additionally, the leaking filling can cause a deepening of the filling beneath the cavity.

Filling Shrinkage

The best care should be taken to truly plug a cavity, but the hole must be exhaustively filled, with no gaps around the edges of the dental restoration. Occasionally, the composite resin used to fill the cavity can shrink as the filling settles, receding from the edges of the cavity and creating an access point. It's through this access point that contaminants can leak into your tooth. 


Increased sensitivity following a dental filling is the most obvious sign of filling leakage. This indicates that irritants are travelling through your dentin tubules, triggering a physical response in the tooth's nerve. A small amount of sensitivity is perfectly natural after a cavity has been filled, although this should quickly subside. When your discomfort lingers or increases, schedule a follow-up appointment with your dentist. 

Ignoring the problem can have serious consequences, and yet fixing the problem is incredibly simple, as your dentist will simply remove the filling before refilling the cavity. They might adjust the composition of the filling material to prevent a recurrence of the issue. For more information about this procedure, contact a general dentist.