Trigeminal Neuralgia and the Experience of Tooth Pain

By Donald R. Tanenbaum, DDS, MPH

Over 25 years ago, Shirley, a 69-year-old female was referred to my office from a prosthodontist who was attempting to complete five restorations in the upper right quadrant. During the course of care Shirley would experience intermittent but acute right facial, jaw and tooth pain in the premolar region that initially eluded diagnosis as her symptoms were not fully suggestive of a pulpal problem and x-rays were equivocal.  Ultimately a referral to an endodontist prompted additional assessment inclusive of diagnostic lidocaine injections which significantly eased her tooth pain that was acute when she arrived at that office. Endodontic treatment followed first on #13 and then as her pain continued in and around #12 (leading to persistent left sided chewing), root canal was also performed on that tooth. On one occasion when Shirley presented to the endodontic office, she was unable to open her mouth, a scenario that had been experienced by her prosthodontist on several visits.

As Shirley continued to suffer  after the root canal procedures with intermittent but concerning pain, pain medications were prescribed and she was referred to my office. Her chief complaints when initially seen were multiple and included:

• Constant achiness in her jaw muscles on the right side
• Periods of limited jaw motion described as a “rolling spasm”
• Pain in teeth #12 and 13 that at times was sharp and intense, while at other times dull and gnawing in it’s character. At times the pain in her teeth completely eased giving her a sense of optimism, but those moments were short lived
• Inability to chew on the right due to increased pain
• Moments of right ear pain

She was using the medications as prescribed but with no predictable benefit.

An examination revealed limited and guarded jaw motion measuring 30-33 mm, that increased to 40 mm following the application of a counter irritant cold spray, ethyl chloride. The masseter, temporalis and medial pterygoid muscles were extremely reactive to palpation on the right side with palpable knotted areas. Her masseters were considerably hypertrophied and bulged visibly when she clenched her teeth. Additional questioning revealed a history of sleep bruxism and oral appliance use when sleeping in the past. A more recent tendency to brace her jaw muscles and put her teeth together during the day was noted.  These new daytime tendencies were apparently being driven by life tensions and anxiety.

Based on her history, symptoms and exam, diagnoses included muscle spasm and guarding, heterotopic pain, (muscle referral to teeth) and awake/sleep bruxism. As she was not wearing an oral appliance while sleeping due to the ongoing dental work a night guard was fabricated. In addition, several sessions of muscle injections were pursued along with home exercises and use of muscle relaxants and the prior prescribed pain medications. After about 6 weeks of treatment, with the dental work on pause, Shirley felt as if her symptoms had eased, particularly the tooth pains.  As a result, she stopped taking the pain medications. At that juncture she decided to travel to Florida for a 6 week stay to visit her grandchildren, knowing, however. that those visits at times could be stressful.

About three weeks after her departure, I received an evening phone call from Shirley who was in her own words “miserable” with jaw and tooth pain and planning on returning to New York.

When she was seen 2 days later. My first remark was “Shirley, Why no lipstick “? (as her signature appearance was bright red lipstick).  Shirley quickly responded, “Dr Tanenbaum, if I touch my lip on the right side, I get excruciating shooting pain into my teeth and face that can last a few seconds or up to a minute.”  At that moment I realized that focusing treatment on Shirley’s muscles was a mistake. Her symptoms were due to a neuropathic pain condition called Trigeminal Neuralgia.

So What Do We Need To Know about Trigeminal Neuralgia (TN)?

Trigeminal Neuralgia (TN) is a type of neuropathic pain which occurs as a result of abnormalities in neural structures, not in the somatic tissues where the pain is felt. It has been classified as a  non-nociceptive pain problem; one which comes from within the nervous system itself. The second and third division of the trigeminal nerve are primarily impacted, though first division neuralgias can occur. The initial experience of episodic attacks of pain called paroxysms, may eventually become more frequent leading to continuous pain in some people. TN occurs most often in people over 50 and is more common in women than men.

In its most recognizable mature form Trigeminal Neuralgia symptoms include sudden attacks of intense pain, often described as a shock-like or stabbing, typically on one side of the face and often focusing in specific teeth. In between these attacks other symptoms include burning and or throbbing in the face, numbness, tingling, or dull aching sensations. The pain can emerge spontaneously and or be triggered by gentle touch of what are called trigger zones on the face.

As with other medical problems, however, symptoms of an incipient TN disorder may not be recognizable and therefore leads the evaluating doctor down  incorrect diagnostic  and treatment pathways. In fact, early on in it’s presentation TN symptoms include; unilateral muscle pain, pain that follows the auriculotemporal nerve pathway, ear and auricular pain, periods of limited jaw motion, and pain with eating. These symptoms can be confused with those associated with a temporomandibular problem and treated as such with limited or no relief being obtained. In addition, the occurrence of specific tooth site pain is common in the early stages of TN. As a result, it has been reported that over 40 % of those ultimately diagnosed with TN start seeking care in a dental office.

When the tooth pain of TN is evaluated, examination findings are often limited, the common results of temperature provocation are absent, and x-rays are unremarkable. As a result, treatment is often deferred and a wait and see approach is often recommended by the dentist.  If the patient, however, continues to experience tooth pain they will return to their dentist who though unconvinced there is a specific tooth problem may initiate care with reluctance. At other times, as an anesthetic block of the symptomatic branch of the trigeminal nerve will totally relieve the reported tooth pain, the dentist and patient are both convinced the problem site has been identified and care is commonly initiated inclusive of root canal therapy. When relief is ultimately not experienced, both patient and dentist become frustrated sometimes leading to treatment of adjacent teeth or comments by the dentist that “everything looks fine, you can’t have pain in that tooth.”

TN Classification

There are several types of TN.

Classic TN: Is the most common type of TN and occurs due to the compression/morphological changes of the trigeminal nerve root by abnormal vascular anatomy. The superior cerebellar artery is often the source of the compression and is most commonly the result of brain sag accompanying the aging process.

Symptomatic /Secondary TN: Symptoms are often indistinguishable from classic TN but caused by a disease or a demonstrable structural lesion other than vascular compression. Structural lesions include intracranial tumors such as an acoustic neuroma, meningioma, schwannomas, and pituitary adenomas. Epidermoid cysts can also lead to nerve compression.  Demyelination disorders such as multiple sclerosis must also be considered.

When no clear cause can be found even after a diagnostic workup inclusive of brain imaging it is considered idiopathic TN. This is the least common type of TN.

The Pain of TN- Helpful Insights To Make An Early Diagnosis

With the understanding that TN driven facial and toothache can be difficult to diagnose, keeping in mind the follow characteristics should be helpful.

1. The patient may have no pain, manageable pain or miserable pain during the course of any given day or even hour.
2. The pain when present can last 10 seconds to 2 minutes.
3. The pain has an electric paroxysmal pattern.
4. The pain can come on spontaneously without any provocation.
5. The pain can be prompted by speaking.
6. The pain can be prompted by gentle touch of the face, lips, alar of the nose or other identified trigger zones.
7. The pain can be prompted by shaving, washing the face, applying makeup, teeth brushing, nose blowing, eating, drinking, or being exposed to the wind.
8. The pain being experienced is not proportional to the stimuli.
9. The pain can be “excruciating” prompting patients not to speak, and or bite on a hankerchief/cork etc..
10. After an intense period of pain, there will be refractory periods where no pain will be experienced. During those refractory periods the pain cannot be brought on.
11. The pain is often accompanied by a facial tic or contracture. This is why TN is also called Tic Doulereux.
12. TN has a precise but widespread distribution that makes anatomical sense based on how the nerves course.
13. The pain is virtually always during the day and does not wake a patient from sleep.
14. If the pain has been present for weeks or months the gingival tissue on the pain side will be inflamed and the teeth covered with plaque due to toothbrush avoidance.
15. The language of pain must be considered. The words bright, sharp, shooting, excruciating, tic like, radiating, twitching and traceable are common. (In fact, when I reviewed Shirley’s initial consultation notes the words “twitching pain” were recorded but were not meaningful to me at that time).

Treatment after Diagnosis

Once diagnosed, TN is most commonly treated with medications which can be extremely helpful for many patients. At times medication combinations are considered if the effectiveness of one single drug drops off. The side effects of these medications can be problematic leading to surgical discussions.

Ani-seizure medications are the first line options and the most commonly used are carbamazepine, oxcarbazepine, lamotrigine, pregabalin and gabapentin. A muscle relaxant, baclofen has proven to be helpful for some patients while duloxetine best known for it’s use in treating depression and anxiety has been effective as well. In the last few years Botox has been used to address TN pain and current research is investigating it’s use intraorally to treat stubborn tooth and gingival pain.

For some, surgical options are necessary and have proven to be effective for extended periods  of time. The most well -known and researched procedure is called MVD for microvascular decompression. Brain stereotactic radiosurgery, known as Gamma Knife and a variety of rhizotomies are also performed routinely with variable success and often a need to repeat within 3-10 years.

Back to Shirley

Once it was recognized that Shirley’s pain was of TN origin, she was provided medications which almost immediately reduced her suffering to a level never achieved with the prior therapies. Ultimately her dental work was completed without complication.

Conclusion

The diagnosis of Trigeminal Neuralgia is one that should be considered when evaluating a patient with toothache pain that is puzzling and or is unresponsive to intervention. By keeping in mind the characteristics of this type of neuropathic pain, making an early diagnosis will be facilitated sparing patients months of suffering and unnecessary dental treatment.

Donald R. Tanenbaum DDS, MPH  is Clinical Assistant Professor, Hofstra North Shore-LIJ School of Medicine;  Clinical Assistant Professor, Dept. of Oral & Maxillofacial Surgery, School of Dental Medicine at Stony Brook University; and Section Head of the TMJ /Orofacial Pain Division , Dept. of Dental Medicine, Long Island Jewish Medical Center. He practices in New York City and Hauppauge, Long Island within New York TMJ and Orofacial Pain.