Non-dental Intraoral Pain
Intraoral pain may also arise from non-dental structures. Oral mucosal malignancies such as squamous cell carcinoma or salivary gland carcinoma may be painful because of ulceration or perineural invasion.
Inflammatory oral mucosal diseases such as oral lichen planus, recurrent aphthous stomatitis, vesiculobullous diseases, and oral mucosal infections such as candidiasis or herpes viruses (herpes simplex, varicella zoster) may all cause significant oral pain. Patients with hematinic deficiencies, diabetes, hematological malignancies, HIV/AIDS, and Behçet's disease may have significant oral mucosal pain and/or ulceration. Examination will usually reveal the associated oral mucosal abnormalities.
Pain may be experienced in the oral cavity, face, and neck because of salivary gland pathology. Blockage of a major salivary gland duct may be due to infection, mechanical obstruction by tumors, docholithiasis, or ductal strictures. Obstruction of the duct will lead to pain as the gland fills with saliva, which cannot be released. Pain due to chronic ductal obstruction typically worsens preprandially or during meal times. Infection of the salivary glands will result in gland swelling, pain, and erythema/warmth of the overlying skin.
Post-Traumatic Trigeminal Neuropathic Pain/Atypical Odontalgia
This definition encompasses intraoral pain that is localized to a non-diseased dentoalveolar structure, such as a tooth or an area of alveolar ridge from which a tooth has previously been extracted. The pain is often described as "burning," "shooting," or "shock-like," and there may be significant hyperalgesia and allodynia of the affected region, often with an associated area of hypoesthesia or dysesthesia. The pain is usually continuous, with some patients experiencing evoked severe episodes. The area is usually clearly defined with little radiation.[19,20] Patients have described it as "nails being hit the whole time" or "kicked in the face and left bruised and burning."
Controversy remains about nomenclature and criteria for these conditions, and in this article, we differentiate them by the presence or absence of a precipitating event. It has been proposed that formal neurophysiological testing would help distinguish those with neuropathic pain compared with inflammatory causes.[20–22] Patients with trigeminal neuropathic pain have an identifiable traumatic episode preceding the onset of the pain. The precipitating event may include physical trauma such as facial fractures, iatrogenic trauma such as restorative, endodontic, or oral surgical procedures (apicectomy, extraction, implant placement), prolonged severe infection of dentoalveolar structures, or dental procedures carried out with ineffective anesthesia. Trigeminal neuropathic pain is persistent and severe, and associated with a high level of psychological distress and a risk of further iatrogenic harm because of patients seeking ongoing dental or surgical interventions for relief of pain.
Atypical odontalgia or persistent dentoalveolar pain refers to a similar clinical presentation without a clear precipitating event.[24,25] "Persistent dentoalveolar pain" is an ontological definition describing the symptoms and signs without attributing a causation or mechanism. Such definitions are developed using analysis of patient interviews.[26,27] These conditions are usually managed along the same pathways as for other neuropathic pain. Until there are internationally agreed diagnostic criteria based on case–control studies and more well-conducted trials have been carried out, treatment of these conditions can vary substantially between clinicians, leaving patients confused and continually consulting in hope that a "cure" will be found.
Headache. 2014;54(1):22-39. © 2014 Blackwell Publishing