Trigeminal Neuralgia: Symptoms, Dental Diagnosis & When Should a Dentist Refer?
By Dr. Vivek Kumar
CrackDental - Clinical Dentistry Simplified
A patient walks into the dental clinic complaining of severe pain on one side of the face. They point towards a particular tooth and say,
The first thought naturally goes towards a dental cause. But what if the tooth is completely normal?
This is where trigeminal neuralgia should be considered in the differential diagnosis.
Trigeminal neuralgia is a neurological pain disorder involving the trigeminal nerve. Because the maxillary and mandibular divisions of this nerve supply sensation to the teeth and surrounding oral structures, patients can sometimes describe the pain exactly like a toothache.
For dentists, recognizing this pattern is important—not only for diagnosis, but also to prevent unnecessary root canal treatment or extraction of a tooth that is not responsible for the pain.
What is Trigeminal Neuralgia?
Trigeminal neuralgia (TN) is a neuropathic pain condition involving the trigeminal nerve, also known as the fifth cranial nerve.
The International Classification of Headache Disorders (ICHD-3) describes trigeminal neuralgia as recurrent unilateral facial pain occurring in brief attacks that are typically electric-shock-like, shooting or stabbing and are often triggered by normally harmless stimuli. [1]
The individual attacks typically last from a fraction of a second up to 2 minutes.
The pain may be extremely severe, despite there being no obvious abnormality in the teeth or oral tissues.
For clinical purposes, TN can be classified into classical, idiopathic and secondary trigeminal neuralgia. Classical TN is associated with neurovascular compression producing morphological changes in the trigeminal nerve root, whereas secondary TN is caused by another underlying disease such as multiple sclerosis or a structural lesion. [1,4]
Why is Trigeminal Neuralgia Important in Dentistry?
V1 – Ophthalmic
V2 – Maxillary
V3 – Mandibular
The maxillary and mandibular divisions are particularly important in dentistry because they provide sensory innervation to the maxillary and mandibular teeth and associated oral structures.
Therefore, a patient with trigeminal neuralgia involving V2 or V3 may believe that the pain is coming from a particular tooth.
This creates an important diagnostic problem.
If a dentist treats the tooth without establishing a dental diagnosis, the patient may undergo an unnecessary root canal treatment or extraction and still continue to experience the pain.
What Does Trigeminal Neuralgia Pain Feel Like?
The patient's description of the pain is often one of the most useful clinical clues.
Patients may describe it as:
Electric shock
Sudden stabbing pain
Sharp shooting pain
Lightning-like pain
Severe facial pain
Sudden bursts of pain
The attacks are usually brief, lasting from a fraction of a second up to about two minutes. They can occur repeatedly, sometimes many times during the day. [1]
In purely paroxysmal trigeminal neuralgia, the patient is typically pain-free between attacks. However, some patients with TN can have concomitant continuous or near-continuous background pain between the attacks. [1]
This is an important point because continuous background pain does not automatically exclude trigeminal neuralgia.
Common Triggers of Trigeminal Neuralgia
One of the most characteristic features is that the pain may be triggered by an otherwise harmless stimulus.
Touching the face
Brushing the teeth
Chewing
Talking
Washing the face
Shaving
Smiling
Swallowing
Cold air
Drinking
A patient saying that “touching my face produces an electric shock” should make the clinician think beyond routine odontogenic pain.
The ICHD-3 specifically describes triggering by innocuous stimuli within the affected trigeminal distribution as a characteristic feature of trigeminal neuralgia. [1]
Trigeminal Neuralgia vs Toothache
This is perhaps the most important part for a dentist.
Not every pain felt around a tooth is caused by the tooth.
| Feature | Trigeminal Neuralgia | Odontogenic Pain |
|---|---|---|
| Pain quality | Electric shock, stabbing, shooting | Aching, throbbing, sharp or dull |
| Duration | Usually seconds to about 2 minutes per attack | Often longer, depending on pathology |
| Pattern | Recurrent attacks | May be continuous or stimulus-related |
| Trigger | Touch, brushing, talking, chewing | Thermal, biting or spontaneous depending on pathology |
| Dental findings | May be absent | Usually an identifiable dental cause |
| Pulp tests | May be normal | Often abnormal when pulp is involved |
| Radiograph | Usually does not demonstrate the cause | May demonstrate relevant pathology |
| Between attacks | Often pain-free in purely paroxysmal TN | Depends on the dental condition |
This table is not intended to replace clinical diagnosis. It simply highlights why the history and dental examination must be considered together.
A Classic Dental Presentation
Consider a patient who says:
“Whenever I brush my lower teeth, I get an electric shock on this side of my face.”
You examine the teeth and find:
No significant caries
No swelling
No sinus tract
No periodontal abscess
No percussion tenderness
No obvious cracked tooth
Pulp tests that do not support pulpal disease
No radiographic pathology explaining the symptoms
The patient then tells you:
“If I don't touch the area, the pain doesn't come.”
This is the point where repeatedly treating teeth should stop.
The pattern is much more suggestive of neuropathic facial pain, with trigeminal neuralgia being an important consideration.
What Should a Dentist Do?
The dentist's role is not necessarily to make the final neurological diagnosis.
The dentist's first responsibility is to determine whether there is a genuine odontogenic cause for the patient's symptoms.
1. Take a proper pain history
Ask the patient:
Where exactly is the pain?
Is it on one side or both?
How long does each attack last?
What does the pain feel like?
Is it electric or stabbing?
What triggers the pain?
Does brushing trigger it?
Does chewing trigger it?
Does touching the face trigger it?
Is there pain between attacks?
When did it begin?
Has the patient already undergone dental treatment for the same complaint?
A good history can sometimes provide more diagnostic information than another radiograph.
2. Perform a Complete Dental Examination
Before considering a non-odontogenic cause, the dentist should appropriately assess possible dental causes.
Depending on the presentation, this may include:
Caries examination
Pulp sensibility testing
Percussion
Palpation
Periodontal examination
Mobility
Occlusal assessment
Examination for cracked teeth
Soft-tissue examination
Appropriate intraoral radiographs
The objective is not to prove that the patient has trigeminal neuralgia.
The objective is to determine whether the clinical findings provide a convincing dental explanation for the pain.
3. Look for Features That Do Not Fit Dental Pain
Certain findings should make the dentist reconsider an odontogenic diagnosis.
For example:
Very severe pain + extremely short attacks + electric-shock sensation + predictable triggers + no adequate dental explanation
is a combination that should raise suspicion of trigeminal neuralgia.
Another important clue is a history of multiple previous dental treatments for the same pain without meaningful improvement.
What Conditions Should a Dentist Rule Out?
Trigeminal neuralgia should not be diagnosed simply because a tooth looks normal.
Other causes of facial and oral pain need to be considered.
Depending on the clinical presentation, the differential diagnosis may include:
Irreversible pulpitis
Symptomatic apical periodontitis
Acute apical abscess
Periodontal abscess
Cracked tooth
Pericoronitis
Temporomandibular disorders
Myofascial pain
Burning mouth syndrome
Post-traumatic trigeminal neuropathy
Persistent idiopathic facial pain
Other neuropathic facial pain disorders
A proper dental examination therefore remains essential.
What is Under the Dentist's Scope?
This is an important practical question.
A dentist can:
Recognize the pain pattern
The dentist should be able to identify when the presentation is suspicious for trigeminal neuralgia.
Exclude an obvious dental cause
Appropriate clinical examination and diagnostic testing should be performed.
Avoid unnecessary irreversible treatment
A tooth should not undergo RCT or extraction simply because the patient feels pain in that region without a dental diagnosis supporting the procedure.
Explain the situation to the patient
The patient should understand that the pain is real even when there is no obvious dental pathology.
Refer appropriately
A suspected neurological cause should be referred for appropriate medical/neurological evaluation.
What is Not Primarily Under the Dentist's Scope?
Once a non-odontogenic neurological pain disorder is suspected, further neurological investigation and long-term management generally move beyond routine dental care.
This may include:
Neurological assessment
MRI evaluation
Identification of secondary causes
Pharmacological management
Monitoring of neurological treatment
Surgical treatment in selected cases
The European Academy of Neurology guideline recommends MRI as part of the diagnostic work-up for patients with trigeminal neuralgia, because clinical features alone cannot reliably exclude secondary TN. [4]
This does not mean that every dentist needs to order an MRI themselves. The important point is that the patient should be appropriately referred so that the necessary neurological assessment and imaging can be arranged.
When Should a Dentist Refer a Patient With Suspected Trigeminal Neuralgia?
Referral should be considered when the clinical presentation is suggestive of trigeminal neuralgia and no convincing dental cause is identified.
Refer when:
1. The pain is electric-shock-like
Especially when the attacks are sudden and severe.
2. The attacks are very brief
Pain occurring in recurrent attacks lasting seconds or up to around two minutes is characteristic.
3. The pain is triggered by normal activities
For example, brushing, chewing, talking or touching the face.
4. Dental examination does not explain the pain
This is particularly important before performing irreversible treatment.
5. Previous dental treatment has failed
Repeated RCTs or extractions without resolution should prompt reconsideration of the diagnosis.
6. There is facial numbness or objective sensory loss
Although sensory examination can be normal in classical TN, persistent sensory abnormalities should raise concern for a secondary trigeminal neuropathy or another underlying cause. [1,4]
7. There are other neurological findings
Facial weakness, visual symptoms, hearing changes or other neurological abnormalities require appropriate medical assessment.
8. The presentation is atypical
Persistent background pain, bilateral symptoms, significant sensory abnormalities or other unusual features warrant further evaluation.
NICE specifically recommends referral for adults with facial pain accompanied by persistent facial numbness or abnormal neurological signs, because these findings can indicate a significant underlying lesion. [3]
For patients with suspected trigeminal neuralgia whose pain remains refractory to treatment, NICE also recommends specialist referral. [3]
Trigeminal Neuralgia and Unnecessary Root Canal Treatment
This is particularly relevant to endodontic practice.
A patient may localize pain to a perfectly healthy tooth.
If the clinician relies only on the patient's localization and performs endodontic treatment without establishing a pulpal or periapical diagnosis, the underlying pain disorder remains untreated.
The result can be frustrating for both the patient and dentist.
Therefore:
Do not perform RCT simply because a patient points to a tooth.
There should be a clear clinical diagnosis supporting endodontic treatment.
The same principle applies to extraction.
How Should the Dentist Explain It to the Patient?
Instead of saying:
“There is nothing wrong with your tooth.”
a better explanation would be:
“Your pain is real, but the examination does not show a dental problem that explains this particular pattern of pain. Because the pain is brief, shock-like and triggered by normal activities, it may be related to the trigeminal nerve. I would recommend a medical evaluation rather than performing unnecessary dental treatment.”
This approach reassures the patient while also preventing unnecessary procedures.
Treatment of Trigeminal Neuralgia
Treatment of trigeminal neuralgia is primarily medical and, in selected cases, surgical.
The European Academy of Neurology guideline also recommends carbamazepine or oxcarbazepine as first-choice long-term medications for trigeminal neuralgia. Other medicines may be considered by specialists depending on the individual patient. [4]
Patients whose pain remains inadequately controlled or who cannot tolerate medical treatment may be considered for surgical treatment by an appropriate specialist team. In classical TN, microvascular decompression is an important surgical option when appropriate. [4]
Therefore, dentists should generally focus on recognition, exclusion of dental pathology and appropriate referral, rather than independently managing long-term neurological treatment.
A Simple Clinical Approach for Dentists
When a patient presents with unexplained facial or tooth-region pain, think systematically:
Patient presents with facial/tooth pain
↓
Complete dental history and examination
↓
Is there a convincing odontogenic cause?
YES
Treat the identified dental condition appropriately.
NO
↓
Ask:
Is the pain unilateral, brief, electric-shock-like and triggered by harmless stimuli?
YES
Suspect trigeminal neuralgia → refer for appropriate medical/neurological assessment.
↓
Are there persistent sensory changes, facial numbness or other neurological signs?
YES
Prompt medical/neurological assessment is particularly important.
NO
Continue the differential diagnosis for other causes of non-odontogenic facial pain.
This simple approach can prevent a common clinical mistake: treating the tooth when the problem is actually coming from the trigeminal nerve.
Final Take-Home Message
For dentists, the most important lesson about trigeminal neuralgia is not memorizing every neurological classification.
It is recognizing the pattern.
When a patient describes:
short-lasting + unilateral + electric-shock-like + recurrent + triggerable pain
and the dental examination does not provide an adequate explanation, think about trigeminal neuralgia.
The dentist's role is to rule out an appropriate dental cause, recognize atypical or neurological features, avoid unnecessary irreversible treatment and refer the patient when indicated.
Sometimes the best treatment a dentist can provide is knowing when not to treat the tooth.
References
1. Headache Classification Committee of the International Headache Society. The International Classification of Headache Disorders, 3rd edition (ICHD-3). 13.1.1 Trigeminal neuralgia; classical and secondary trigeminal neuralgia. International Headache Society.
2. National Institute for Health and Care Excellence (NICE). Neuropathic pain in adults: pharmacological management in non-specialist settings (CG173). Recommendation 1.1.13: carbamazepine as initial treatment for trigeminal neuralgia.
3. National Institute for Health and Care Excellence (NICE). Suspected neurological conditions: recognition and referral (NG127). Recommendations on facial pain, persistent facial numbness and trigeminal neuralgia.
4. Bendtsen L, Zakrzewska JM, Abbott J, et al. European Academy of Neurology guideline on trigeminal neuralgia. European Journal of Neurology. 2019;26(6):831–849. doi:10.1111/ene.13950.
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