Root canal treatment in Salisbury

Why Does My Tooth Hurt?

Written by Dr Lucas Gervastri

What is tooth ache / tooth pain?

Pain is derived from the Latin word peona, which means punishment. However, as with other pain in the body, we know that dental pain is a protective mechanism. It occurs when tooth or gum tissue is being damaged signalling to the individual that action should be taken to remove the cause.

Until the 18th Century it was thought that the cause was a burrowing worm parasitically devouring the tooth. This perception may have been because a diseased tooth nerve has a  worm-like appearance. In a healthy living tooth the nerve is located in a central pulp chamber encased by two distinct layers: an outer layer of enamel and an inner layer of dentine. When these protective layers are affected the nerve becomes inflamed and eventually becomes infected.

A short, sharp ‘nervy’ pain

Despite being the hardest substance in your entire body enamel is not impervious to physical and chemical assault. Loss of enamel and exposure of the underlying dentine to the surrounding environment can be caused by decay, acid erosion or by cracking of the teeth. In these situations the pain can be worsened by changes in the temperature (cold and hot) and pressure (eating / biting, particularly sweet foods).

When tooth dentin is exposed to triggers in the mouth, it causes fluid to shift inside of the dentin [tubules] which affects the nerve and results in pain. Knowing what triggers the pain can help us to pinpoint the cause.

Tooth decay

Tooth decay is when the tooth structure is destroyed by the acidic products of oral bacteria which feed on dietary sugars. The mouth is home to over 700 types of bacteria but if it wasn’t for one species, Streptococcus Mutans which feeds on sucrose (sugar), dental decay would not be a common problem. In the communities of the world where people consume traditional diets free of refined sugars tooth decay is a rarity. 

Once dental decay has perforated the enamel layer it spreads more rapidly into the dentine rendering it soft and mushy. Often the decay can progress for a while without any symptoms.

Tooth decay formation step by step, forming dental plaque and finally caries and cavity

Routine dental examinations allow for the detection of decay early on when limited intervention can prevent its progression. By the time the pain arises the decay is often already deep. The placement of a well-sealed filling after excavating the infected enamel and dentine is usually sufficient enough to abate sensitivity. If decay has affected a lot of tooth structure a crown or an onlay may be needed to restore tooth integrity.

Unfortunately, post-operative pain can occasionally arise particularly if the filling is deep / close to the nerve. This will often stabilise after a couple of days, but if it is too close to the nerve, the nerve will be irritated and eventually die and a root canal treatment (removal of the nerve) will be necessary.

Cracked tooth syndrome

If a short, sharp pain is triggered by biting pressure and cold it could be that a filling or the tooth itself is cracked, perhaps from biting down on an olive pit or something similar. The flexing motion of a cracked cusp, usually when it snaps back on the release of the bite can cause sudden movements of fluid which pushes / pulls on the nerve fibres.

Usually, with a cracked tooth the recommended treatment is to have a dental crown or an onlay made which acts to stop the cusp from flexing further. However, if the crack is extended close to the nerve the tooth may still require root canal treatment or extraction.

Toothache caused by acid erosion and grinding

Tooth wear can arise when someone chronically grinds their teeth, eats too much acidic food or brushes their teeth too hard. If it happens gradually it is not usually attended by any pain as the dentine has time to repair itself. If the process is quicker, it will result in sensitivity.

The treatment usually involves reduction of acidic food intake and a switch to a toothpaste containing stannous fluoride (tin fluoride). The tin compound can be effective in plugging the exposed dentine tubes and can help to arrest further sensitivity. If this fails, the dentine may need to be sealed off with a filling.

Sometimes extensive grinding or clenching teeth can create bruising type injury to a tooth and it to become tender for a few days before slowly recovering and firming up again. Tooth grinding and clenching or a problem with your bite such as a filling placed too high can also stress the ligament around the tooth and cause discomfort.

You might be advised to consider wearing a protective nightguard at night to relieve the pressure exerted by grinding and clenching.

A constant dull ache

If on the other hand, the pain is persistent, the nerve could be affected and in the worst case scenario, infected.

This pain often starts off as dull and aching and soon acquires a more intense and throbbing sensation. Often it can become almost intolerable, feeling as though it has spread to whole side of the head and face. The severity of the pain is accounted for by the fact that the highly vascular and innervated pulp is trapped within the rigid walls of a chamber where swelling is impossible and inflammatory products cannot escape. The pain is often worse on hot temperature whereas cold temperature may provide some relief. This type of nerve pain is called pulpitis.

Hidden caries in to molar tooth. Medically accurate 3D illustration

At this stage, the nerve of the tooth is irreparably damaged. The nerve will need to be removed and the pulp chamber sealed off with a root canal filling. An alternative is to extract the tooth. If nothing is done then the pain will eventually go away on its own because the nerve tissue dies off. However, it is important that the tooth is still treated.

If a tooth with a dead nerve is forgotten about, the pain will sooner or later re-emerge. The new pain will no longer be affected by hot or cold but instead by touch. This happens because the decomposing nerve will start to irritate and then infect the jawbone. Pus is formed which will either find its way to the surface of the gum or escape into the cheek and surrounding tissue. This is known as a dental “abscess” and the treatment for this remains the same; the tooth needs either root canal treatment or extraction and the sooner it is done the better the prognosis. 

Periostitis tooth – Lump on Gum Above Tooth. Medically accurate dental 3D illustration

Localised gum pain

Sometimes problems with the gums can mimic the sort of pain that comes from an inflamed or infected tooth nerve. This can be localised inflammation caused by food or plaque wedging in the gum between the teeth. An example of this is a wisdom tooth infection called pericoronaritis.

Since the wisdom teeth make their appearance long after the jaw has stopped growing, they often have insufficient space to erupt or they can be laying in the jaw at a wrong angle for full eruption. Bacteria can collect under the flap of the gum overhanging a partially emerged wisdom tooth causing it to become excruciatingly painful and swollen. This can be treated by cleaning the impacted food and bacteria from underneath the flap, a course of antibiotics or extraction of the partially erupted tooth.

Healthy teeth and wisdom tooth with mesial impaction . Medically accurate tooth 3D illustration

Generalised gum pain

Chronic gum disease in its end stages also causes pain and looseness of the teeth. Rather like icebergs, healthy teeth are two thirds of a tooth’s length submerged in the jawbone. If the gums are not kept healthy by maintaining good oral hygiene, you can develop gum disease which is also called chronic periodontitis. Gum disease can be genetically determined (a family trait) and can be worsened by smoking or certain diseases such as diabetes.

This disease is caused by bacterias creating colonies around the gums. Gums become infected and the bone recedes. This is why keeping your gums healthy by flossing or using interdental brushes and regularly seeing a hygienist is as important as brushing twice daily. Your gums should always be firm and pink in colour and if they bleed when you floss this is your body’s way of telling you that you are not flossing often enough. 

In the case of gum disease it is advised to see a hygienist with advanced training and expertise in this field ideally working under the supervision of a Registered Specialist Periodontist or in more advance stages it may be necessary to be treated directly by a Registered Specialist Periodontist.

Periodontitis is a inflammatory diseases affecting the periodontium, the tissues that surround and support the teeth

Other causes of tooth ache / pain

Occasionally, toothache can have non-dental causes such as a sinus infection and resultant pressure and toothache on upper teeth. Another condition that can give rise to a very painful toothache is Trigeminal Neuralgia which is usually caused by compression of the trigeminal nerve which is the common nerve supply to all the teeth.

If the situation remains unclear after most dental causes of pain have been ruled out by examination and x-rays, a referral to the correct Registered Dental Specialist is advised.

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