Do you need urgent care and referral?

URGENT treatment (within 30 hours) is indicated in endodontic (Root canal) and implant related nerve injuries. Ideally referral is recommended based on the cause of injury

The trigeminal nerve is the large sensory nerve that supplies feeling to your face, mouth, eyes, nose and scalp. Nerve injury can sometimes result from dental treatments such as dental injections, root canals, insertion of dental implants and removal of teeth or other surgical treatments. These dental injuries affect the trigeminal nerve usually the lower lip or tongue areas— causing a mixture of pain, numbness and strange sensations that may be present all the time or intermittently.

Signs and symptoms – What you may be experiencing

70% of our patients report numbness at rest with either ongoing or intermittent pain. Only 30% have reduced sensation overall. Some patients report pain to touch and or pain on cold drafts or foods. Trigeminal nerve injuries can cause episodes of intense, stabbing, electric shock-like pain in the areas of the face where the branches of the trigeminal nerve are distributed — the lips, eyes, nose, scalp, forehead, upper jaw and lower jaw. Sometimes you may notice pain with touch or when a cold breeze hits your face.

Due to the pain, Trigeminal nerve injuries can be extremely distressing for patients. Although some patients regain normal sensation and function within a few weeks or months, some are left with abnormal sensation or pain, which can cause long term problems with speech, drinking, kissing, brushing teeth and chewing. The psychological impact must not be underestimated due to pain and functional problems related to these nerve injuries.

Recommended timing for intervention

Depends upon the cause of nerve injury and the duration since the cause;

• Suspected nerve section: should be referred or undergo immediate exploration / repair
• Endodontic treatment/ root canal: < 24-30 hours to remove endo over fill or over instrumentation or tooth (be warned that Endo nerve injuries can take 2-3 days to onset, due to chemical leakage out of the tooth apex next to the inferior dental canal [IDC])
• Implant placement: < 24-30 hours to remove to remove implant
• Wisdom tooth:
  • Lingual nerve injury related to buccal approach: immediate referral for exploration and repair (CBCT assessment of any damage to the lingual plate post-surgery can expedite surgical assessment and repair)
  • Lingual nerve injury related to lingual access: these injuries may resolve in 88-90% of cases over 12 weeks
  • Inferior alveolar nerve suspected section: Immediate referral (Order a post-surgical Pan oral radiograph, if tooth roots are present, if they are, take a CBCT to assess the relationship of those roots to the IDC and arrange root removal with nerve repair if required) Thus, assess the patient within 2 weeks

Non urgent referrals the timing of consultation is less important but we try to see most patients within 4-6 weeks of referral

• Implant nerve injuries > 4 days
• Root canal endo injuries > 4 days
• Wisdom tooth
  • lingual nerve injury related to lingual access >12 weeks
  • inferior alveolar nerve injury >12 weeks
• Injection or local anaesthetic > 3-6 months
• Orthognathic > 3-6months
• Fracture > 3-6months

If you have had surgery or dental treatment and you notice any of the effects listed above after a local anaesthetic should have worn off – say 6 hours later – it is really in your interest to seek advice from the surgeon/hospital/dentist.

With any nerve injury you may ask your dentist to prescribe you short term high dose steroids and anti-inflammatory medication to minimise inflammation around the damaged nerve or elect to take some Folic acid supplements, but there is no evidence base to support this practise.

There is moderate evidence to support nerve regeneration using these medications (Sun H, Yang T, Li Q, Zhu Z, Wang L, Bai G, Li D, Li Q, Wang W. Dexamethasone and vitamin B(12) synergistically promote peripheral nerve regeneration in rats by upregulating the expression of brain-derived neurotrophic factor. Arch Med Sci. 2012 Nov 9;8(5):924-30. doi: 10.5114/aoms.2012.31623. Epub 2012 Nov 7. PMID: 23185205; PMCID: PMC3506245: Julian T, Syeed R, Glascow N, Angelopoulou E, Zis P. B12 as a Treatment for Peripheral Neuropathic Pain: A Systematic Review. Nutrients. 2020 Jul 25;12(8):2221. doi: 10.3390/nu12082221. PMID: 32722436; PMCID: PMC7468922).

Medical Regimen for early days post nerve injury

1. Steroids

• Prednisolone oral dose may be from 5 mg to 60 mg per day
  • Suggested dosage day one post injury 50mg, day 2 40mg, day 3 30mg, day 4 20mg and day 5 10mg, or
• Dexamethasone oral dose is 0.75 mg to 9 mg daily
  • Day1 5mg, day2 4mg. day3 3mg, day4 2mg, day 5 1mg

NOTE: You should not be prescribed steroids if you have a history of gastric or duodenal inflammation or ulceration

2. Vitamin B12

• Oral Vit B12 (methylcobalamin) 500 µg three times daily, or
• Intramuscular injections either 500 µg methylcobalamin three times a week (n = 12), or weekly dose of 1500 µg on a single occasion

3. Non-steroidal anti-inflammatories (NSAIDs)

• Ibuprofen 400-600mg 6 hourly

4. If you are experiencing severe neuropathic pain:

• Tricyclic anti-depressants (for ongoing background burning pain)
  • Nortriptyline starting dose 10 and build up to 40mg daily (increase dose 10mg weekly if tolerated) at night
• Gabapentinoids (for sharp shooting neuralgic pain either ongoing or caused by touch)
  • Pregabalin 25-75mg once (night time) to 3 times daily depending upon the side effects and pain relief benefit, or
  • Gabapentin 100-300mg once a day night time (Maximum dose 1800-3600 mg/day in 3 divided doses)

Alternative regimen containing 50mg uridine monophosphate, 3 µg B12 and 500 µg folic acid to treat pain in peripheral neuropathy.