Burning Pain and Numbness After an Implant
Mr. K is a 47-year-old warehouse supervisor referred for 18 months of constant right mandibular pain. The pain began immediately after placement of an implant at site #31 and has never resolved. It is deep, burning, and rated 5–6/10; it does not wake him, but it is present every day. He describes numbness and pins and needles of the right lower lip and chin. Light touch to the right chin feels unpleasant, and pinprick is sharper than on the left. He has seen three dentists; the implant is osseointegrated, and a CBCT shows no sinus or periapical disease. Ibuprofen 600 mg provides no relief. He grinds his teeth and has morning jaw tightness. Jaw opening is 42 mm without deviation; there is no TMJ or masseter tenderness. He takes sertraline 50 mg daily for depression. He is angry and asks whether the implant should be removed.
1. What is the most likely diagnosis, and how does it differ from trigeminal neuralgia and painful temporomandibular disorder? Which clinical features support your reasoning?
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Most likely painful post-traumatic trigeminal neuropathy (PPTTN) of the right V3, meeting ICHD-3 criteria: pain in the trigeminal distribution, caused by trauma from implant surgery, persisting more than 3 months, with sensory changes including numbness, allodynia, and hyperalgesia, and no better explanation.
Trigeminal neuralgia is episodic, electric-shock-like, lasts seconds to 2 minutes, has trigger zones, and usually produces no sensory loss. Painful TMD is movement-related, with muscle or joint tenderness, and does not cause numbness. Odontogenic pain would be provoked by percussion or thermal testing, or show periapical changes; the CBCT is clear.
The constant burning pain, altered sensation, and onset after surgery are the key features. Normal jaw range and absence of muscle tenderness argue against TMD as the primary cause. His bruxism may be a maintaining factor, not the diagnosis.
2. What investigations, if any, are indicated now? Explain the role of MRI and whether you would remove the implant.
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An MRI of the brain with thin slices through the trigeminal nerve, such as FIESTA or CISS sequences, is reasonable to exclude a structural lesion, especially because he has sensory loss. However, the clear temporal link to trauma and concordant examination make a central lesion unlikely. If MRI is unavailable or he cannot tolerate it, document the reasoning and monitor.
Repeat CBCT is not indicated unless new symptoms suggest implant failure or infection. Vitality testing of adjacent teeth can exclude occult odontogenic pain. Blood work is not routinely needed. The most important assessment is a careful sensory examination mapping the distribution. Do not remove the implant solely for pain: removal does not reliably relieve neuropathic pain and may worsen it. Refer to neurology or an orofacial pain specialist if the diagnosis remains uncertain.
3. Outline a pharmacologic and nonpharmacologic plan, including starting doses, monitoring, and what you would avoid.
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First-line pharmacotherapy: gabapentin 100–300 mg at bedtime, titrated every few days to 300 mg three times daily and then up to 1,800–3,600 mg/day in divided doses as tolerated; or pregabalin 75 mg twice daily, titrated. A tricyclic such as nortriptyline 10–25 mg at night, or duloxetine 30–60 mg daily, is an alternative, especially with depression. Topical lidocaine 5% patch to the painful area can be used. Avoid opioids and repeated surgical interventions.
Monitor sedation, dizziness, renal function, and mood. Nonpharmacologic care includes CBT, pain education, sleep hygiene, and management of bruxism with a guarded night guard if indicated. Set realistic goals: partial pain reduction and improved function, not cure. Coordinate with his mental health provider because sertraline may interact with additional serotonergic drugs. Follow up in 4–6 weeks.