An unpleasant taste emanating from a dental crown signals an underlying problem. A healthy crown should feel and taste no different from a natural tooth, integrating seamlessly into your mouth’s environment. When a sour, foul, or metallic taste develops, it usually indicates an issue beneath or around the crown, not the crown itself. Causes generally fall into two categories: issues related to the crown’s physical fit or composition, and biological factors like infection or decay.
Issues Related to Crown Material and Fit
The cement used to bond the crown to the tooth is one potential source of an altered taste. Immediately after the procedure, residual cement may cause a temporary, slightly chemical taste. This taste is typically short-lived and should resolve completely within a few days or weeks as the area heals and the mouth adjusts.
A more common and persistent issue is structural failure, known as crown leakage or a marginal gap. The crown is meant to form a tight, protective seal at the gumline, known as the margin. If this seal breaks down, even microscopically, it allows saliva, food debris, and oral bacteria to seep into the space between the crown and the prepared tooth. This trapped material stagnates and decomposes, producing a foul taste that cannot be resolved by brushing or rinsing.
The crown material itself can cause a metallic taste, especially with older restorations. Crowns made of non-precious metal alloys or porcelain-fused-to-metal (PFM) contain metallic ions that may corrode when exposed to saliva. This corrosion releases metal ions, triggering a bitter or metallic sensation. All-ceramic or zirconia crowns are generally taste-neutral and rarely cause this specific issue.
The Role of Infection and Hygiene
The most significant cause of a foul or sour taste is biological: an active infection in the surrounding tissues or the tooth beneath the crown. Periodontal disease (gum infection) often starts at the crown margin where bacteria accumulate. This infection leads to the formation of periodontal pockets, which harbor bacteria that produce volatile sulfur compounds (VSCs). These VSCs are the primary source of the persistent, rotten, or sour taste associated with gum disease.
Inflammation around the crown, sometimes accompanied by pus discharge, indicates a bacterial overload. This condition is exacerbated if the crown’s margin is rough or sits too deep beneath the gumline, making effective cleaning impossible.
Recurrent decay occurs when bacteria infiltrate the tooth structure underneath the crown through a compromised marginal seal. Once decay begins, the bacterial activity breaks down the remaining tooth material, creating a cavity that generates a distinctly unpleasant, often sour taste. This decay can progress silently beneath the crown, causing the foul taste to be the first noticeable symptom before pain or sensitivity sets in.
Poor daily oral hygiene, such as inadequate flossing or brushing specifically around the crowned tooth, accelerates both gum disease and recurrent decay. The margin where the crown meets the tooth is highly vulnerable, and neglecting to clean this area allows plaque to solidify and become a bacterial reservoir. This buildup then drives the infectious processes that create the noticeable bad taste.
Consulting Your Dentist and Treatment Options
A persistent or worsening bad taste around a crown requires an immediate visit to your dentist. Waiting allows infection or decay to progress significantly, risking tooth loss. Any accompanying signs, such as swelling, bleeding when brushing, pain upon biting, or a feeling of looseness, indicate a more urgent situation.
The diagnostic process begins with a thorough visual inspection to check the crown’s margins and the surrounding gum tissue for inflammation or gaps. Your dentist will use a probe to measure the depth of the gum pockets around the tooth and will take X-rays to check for bone loss or any signs of decay beneath the crown. Checking the bite is also important, as an ill-fitting crown can cause nerve irritation and taste disturbances.
Treatment pathways are determined by the underlying cause identified during the examination. If the issue is primarily gum inflammation, a professional deep cleaning or periodontal therapy to remove hardened bacteria and plaque may resolve the taste issue. When the taste is due to a failing crown seal or recurrent decay, the existing crown must be removed and the underlying tooth structure treated. This treatment may require a filling, a root canal procedure, or a new, better-fitting crown to restore the protective seal and prevent future infiltration.