If your tooth tastes bad, there are several possible reasons for this.
Infection can result in a bad taste or bad breath
The most common reason your tooth tastes bad unrelated to your diet is infection. Whether it is discharge from an abscess emptying into your mouth, or there is an infection present in the gum or jawbone, you will likely notice a bad taste from that.
In most cases, there is no pain connected with the early stages of infection, so you can have this issue for days, weeks, or even months before you begin to have any pain from it. Unfortunately, all that time, the infection is spreading, and the bacteria can get into your circulatory system, harming other organs such as your heart or your pancreas. This places you at a much higher risk of heart disease, stroke, or diabetes.
The bad tastes that you may experience can truly fluctuate, so it is tricky to label it. However, most patients describe it as bitter, sour, or simply unpleasant. If you notice anything like this coming from your tooth, you need to ask your dentist about potential infections as soon as possible.
Bad, old, or poorly maintained fillings can result in a bad taste or breath
The second thing that could cause a persistent bad taste is bad dental fillings. If your dental fillings are falling apart, it can cause a metallic taste. Over time, old silver mercury fillings can erode where they seal against the tooth. This will let bacteria into the tooth, which can also cause a bad taste in the mouth.
The primary danger of older fillings:
The primary danger with older fillings is the further tooth decay that can form. If the problem is identified early, the filling can essentially be replaced. However, if left untreated more work will likely be needed in order to save the tooth.
Other potential explanations behind a bad taste or bad breath
There are several other things that can cause a bad taste in the mouth, including:
Gases from your stomach: sometimes, gas and stomach acid can come up from your stomach, creating a bad taste.
Bacteria in the mouth can result in a ‘spoiled egg’ gas: this is less bad taste and more bad breath. This issue can generally be managed with prescription mouthwash.