Differential Diagnosis of Odontalgia (Dental Pain)

Common features of Odontogenic pain

• Presence of etiologic factors for an odontogenic origin, (e.g. Caries, leakage of restorations, trauma, fracture).
• Ability to reproduce chief complaint during examination.
• Pain reduction by local anesthetic.
• Unilateral pain.
• Pain Qualities: dull, aching, throbbing.
• Localized pain.  
• Sensitivity to temperature.     
• Sensitivity to percussion , digital pressure.

Selected features of Non-odontogenic pain

• NO apparent factors for odontogenic pain, (e.g. no caries, leakage of restorations, trauma, fracture) .
• No consistent relief of pain by local anesthetic.
• Bilateral pain or multiple painful teeth.
• Chronic pain that is no responsive to dental treatment.
• Pain Qualities: Burning, electric shooting, stabbing, dull ache.
• Pain that occurs with a headache.
• Increased pain associated with palpation of trigger point or muscles.
• Increased pain associated with emotional stress, physical exercise, head position, etc.

Mechanisms of Non-odontogenic pain

Referred pain explained by CONVERGENCE. Certain afferent sensory nerve neurons have peripheral terminals that innervate different tissues, yet their central terminals converge onto the same second-order projection neuron located in the trigeminal nuclear complex.

A Systemic Disorder that interacts with pulpal or periradicular tissue. The systemic disorder serves as an etiologic factor for pain that originates from pulpal or periradicular nociceptors but is not derived from dental pathoses, thus dental treatment is ineffective in reducing pain. (e.g., HERPES ZOSTER, MALIGNANT NEOPLASIA, SICKLE CELL ANEMIA AND DEVELOPMENTAL DISORDER.

Psychosocial or behavioral factors may contribute to the perception of chronic craniofacial or dental pain. (e.g. Somatoform pain disorder and Munchausen syndrome)

Types of Non-odontogenic pain

1. Non-odontogenic dental pain of musculoskeletal origin

• Myofascial pain: Temporomandibular dysfunction 

Etiology: this classification is an umbrella term for several chronic pain disorders involving masticatory and proximate muscles and the Temporomandibular joint (TMJ). 

Muscles involved:

• Superior belly of the Masseter muscle - Maxillary Posterior Teeth
• Inferior belly of the Masseter muscle – Mandibular Molar Teeth
• Anterior Digastric muscle – Mandibular Anterior Teeth
• Temporal muscle – Maxillary Anterior or Posterior Teeth

2. Non-odontogenic dental pain of neuropathic origin

• Trigeminal neuralgia – (tic douloureux)

 Unclear etiology. Vascular compression of the trigeminal nerve is a common hypothesis.

• Atypical Odontalgia - (Phantom toothache, deafferentation pain)

Unknown etiology but is often associated with trauma or inflammation in the region. Hx of lack of response to multiple endodontic treatment s or extractions. Pain may change location with time. 10 times more prevelant that trigeminal neuralgia. 3% of patients receiving pulpal extirpation may actually have atypical odontalgia.

• Glosspharyngeal neuralgia

Unknown etiology but may involve vascular compression of the Ninth  cranial nerve. Severe, shock like pain that lasts for only a few seconds. Elicited by swallowing, talking or chewing. No pain referred to teeth. Distribution of pain includes the posterior mandible, oropahranyx, tonsillar fossa and ear.

• Neuralgia inducing cavitational oseomylelitis/osteonecrosis - (NICO)

Hypothesis that certain forms of chronic orofacial pain are caused by cavitation defects in the mandible or maxilla, a condition called NICO. Propose etiology is chronic inflammation or c=necrosis from bacterial osteomyelitis or vascular pathosis following extraction.

Controversial and not supported by scientific evidence.

3. Non-odontogenic dental pain of neurovascular origin

• Migraine - Migraine with aura - (Classic migraine), & Migraine without Aura - (Common Migraine)

Unknown etiology, a neurovascular hypothesis postulating vasodilation of cephalic and cerebral arteries with activation of sensitized perivascular nociceptors.

Pain is characterized by: pain not restricted to a tooth (i.e., diffuse pain); unilateral dull, throbbing pain quality, pain unrelieved by a diagnostic block and pain not altered by intraoral thermal stimuli.

•  Cluster Headache (Sluder neuralgia)

Unknown etiology but hypothesized to be caused by episodic vasodilation activating perivascular nociceptors. The term Cluster denotes the observation that these pain episode often last 6 to 8 weeks and then are followed by relatively long pain free period.

Pain is not restricted to a tooth (i.e. pain includes retro-orbital and sinus regions) pain exacerbated by drugs or occurring during sleep, pain unrelieved by diagnostic intraoral anesthetic block and pain not altered by intraoral thermal stimulation. Pain distribution is maxillary posterior teeth, sinus and retro-orbital areas. Rhinorrhea, nasal congestion and lacrimation from the involved eye may occur.

4. Non-Odontogenic dental pain due to inflammatory conditions

Sinusitis

Etiology: (1.) Bacterial infection and (2.) allergies. Both referred pain and an acute neuritis of dental nerves leaving the apical foramina and coursing through the floor of the sinus occurs. Pain is not restricted to a single tooth. Patients report a sense of pressure or fullness in the infraorbital region over the involved sinus. Malar and Maxillary alveolar regions are involved. Teeth in area test VITAL.

5. Non-odontogenic dental pain due to systemic disorders

Several systemic disorders can lead to non-odontogenic pain.

• Cardiac Pain – Left posterior mandible not relived by local anesthetic.
• Herpes Zoster – Dental pain preceding the eruption of vesicles. Mixed case reports, with some with pulpagia like symptoms and others reporting necrosis with PA radiolucencies.
• Sickle cell anemia - Patients with Sickle Cell anemia may present with non-odontogenic pain. And

In a 12 month study, 68% of 51 patients with sickle cell anemia reported dental pain with no evident dental pathosis.

• Neoplastic Disease – reports of dental pain as an initial or sever symptom in patients with glioblastoma multiforme, osteoblastoma, metases from breast, lung or prostrate; osteoma, carcinoma, sarcoma, non-hodgkin lymphoma and Burkitt lymphoma. Key findings that prompted consideration of non-odontogenic origin of the dental pain included subsequent paresthesia or anesthesia, positive response to pulp testing, failure of dental treatment, diffuse or spreading nature of pain, unusual appearance to radiographic lesions.

• Multiple Sclerosis – may be the initial presenting symptom in a patient with MS.  Felt like a toothache with no associated dental pathosis then progressed to “electric” shock like pain.

• Menstrual Cycle – Pulpal pain correlated with menstrual cycles has been reported

6.  Non-odontogenic dental pain of psychogenic origin - (Idiopathic pain disorder).

Patients who have pain that is caused by psychogenic mechanism are appropriately placed in this category The term Somatoform pain disorder is used to describe a cognitive perception of pain that has no demonstrable physical basis. Four sub-types include: somatic delusion, somatization disorder, depression & converson.

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