Teeth seem like solid bone, why is that they ever ache? Typically the pain is around the tooth. For a cavity to start causing pain, it actually has to wear through the enamel and reach the dentin under the enamel, and the dentin actually has nerve fibers able to feel pain.

Dentin is calcified tissue that is found directly beneath the enamel, and is the second largest component of any given tooth. When your tooth itself aches, the aching sensation typically starts with the dentin. Tooth sensitivity is caused when the dentin is exposed to drastic temperature changes, acidic food or beverages, and sugars the sugars food or beverage. This is why really cold drinks cause pain to your teeth once the enamel has worn down.

Often times tooth aches are caused by abscessed teeth, when the root or pulp of the tooth has become infected.

The severity of a tooth ache can range from chronic (intense persistent pain) to mild (a dull and inconsistent pain). Dental causes of tooth pain are:

Dental Cavities. Dental cavities are caused when a whole is formed in the enamel leading to the dental. When left untreated, id leads to an abscessed tooth.

Tooth Decay. Tooth decay occurs when decay works its way to the pulp of the tooth causing it to become infected, again if left untreated it leads to an abscessed tooth.

Cracked teeth. When a tooth splits or fractures, it leaves the opportunity for the tooth to become inflamed and infected.

Periodontal disease. The pain typically comes from when a tooths root becomes exposed, often because of a receding gum line. This makes them more sensitive to hot and cold foods. The periodontal disease itself can cause pulpal inflammation by traveling down small canals that extend from outside the tooth to the inside called lateral canals.

Typical pain symptoms and potential problems.

In all cases, once notable dental pain occurs, you should visit a dentist. An infection runs the risk of reaching your brain and causing serious pain and even death to a person when left untreated and having pain dealt with by a medical professional is always the recommended route.

Momentary sensitivity to hot and cold. This pain is typically caused by exposed dentin or a receding gum line giving more sensitivity to the root of a tooth. This can also be cause by having a loose filling of a fractured tooth. This can also occur because of inflamed pulp, causing temporary sensitivity. This is common if you have had recent dental work.

Lingering pain caused by hot or cold. This is typically irrevocable damaged done by exposed dentin or periodontal disease. This can also occur because of a fractured tooth.

Dull ache near a tooth, biting sensitivity. Biting sensitivity tends to be a sign of inflamed pulp or possibly related to how you are actually biting. An inflamed pulp could be caused by recent dental work or another agent causing abnormal inflammation.

Sharp Pain when biting down. This is almost always a sign of a cracked or split tooth, or a loose filling. It is possible it is something such as root canal pain, but typically it has something to do with a broken tooth, and you should visit the dentist as soon as possible.
Constant and severe pain, sensitivity to even being touched. This is typically caused by the aforementioned abscessed tooth, causing the surrounding bone to become infected.