Numbness in the mouth, either the temporary or prolonged loss of sensation on the tongue, lips (most often the lower lip) or any other place difficult to locate inside the oral cavity, or the sensation of tingling or itching are all signs of oral paresthesia. These sensations usually appear suddenly and can fluctuate considerably during the same day.

The symptoms associated with oral paresthesia, frequently described as persistent numbness in the mouth, are numerous and vary according to the causes associated with it. This may be a

• swelling and/or burning around the tongue, sometimes extending to the rest of the oral cavity;
• stinging, tingling, prickling, itching;
• loss or taste disorders;
• halitosis;
• speech difficulties;
• xerostomia (dry mouth).

The causes of oral paresthesia are numerous and cover a wide spectrum of problems ranging from superficial disorders to serious conditions requiring rapid diagnosis.

In all cases of numbness in the mouth, it is recommended to consult your attending dentist as soon as possible.

Numbness in the mouth may result from

• the consumption of a very cold or very hot substance. The numbness will disappear on its own after some time;
• an allergic reaction to a food or drug;
• a migraine state. Numbness may be one of the symptoms of migraine;
• a local anaesthetic, performed by the dentist to perform a treatment. The sensation of numbness, which is completely normal, can last up to 3 or 4 hours after the operation;
• a complication following local anesthesia. In rare cases, temporary or permanent paresthesia may occur when the needle used to inject the anesthetic has inadvertently touched a nerve. This complication is mainly related to the extraction of wisdom teeth;
• nerve compression, due to the presence of a cyst or tumour in the vicinity;
• untreated conditions, such as cavities or abscesses, can also cause nerve compression and numbness;
• certain systemic conditions such as diabetes, multiple sclerosis, leukemia and lymphoma can cause numbness in the area of the mouth;
• cancer of the oral cavity or tongue.

Anxiety and depression have recently been identified by some specialists as likely causes of oral paresthesia symptoms. This is referred to as “psychogenic oral paresthesia” (C. Husson-Bui and R. Kuffer, 2010).

The treatment recommendation will be provided by the attending dentist who alone is able to make a diagnosis. Depending on the identified cause of the numbness, it may occur

• decompression of the affected nerve, according to the most appropriate method;
• root canal treatment, if the numbness is caused by untreated decay that has infected the dental pulp and reached the nerve or by a periapical abscess;
• management of inflammation, infection and/or edema with prescribed antibiotics or anti-inflammatories.

In more severe cases, especially if a malignant tumour is suspected, the patient may be referred to an oncologist, a cancer specialist.

Numbness in the mouth should never be taken lightly. Consult your dentist as soon as possible to clarify the causes of paresthesia.

It is essential to act quickly in case of oral paresthesia. The longer it takes to treat the cause of the numbness, the greater the risk that paresthesia will become permanent.

Some lifestyle habits can be modified to reduce the risk of oral paresthesia. It is recommended, among other things, to

• avoid consuming substances that are too hot or too cold. Extreme temperature changes can affect your oral health;
• avoid smoking and consuming any other tobacco products that increase the risk of developing oral cancer;
• reduce alcohol consumption, which is also a significant risk factor for oral cancers.

Good oral hygiene measures are also essential:

• Brush your teeth 2 to 3 times a day and floss;
• Consult your dentist once or twice a year, or as recommended by your dentist, to prevent the development or aggravation of infections and diseases of oral origin;
• Don’t wait to treat a mouth condition. Act quickly before your oral health deteriorates and requires more invasive treatments.