general practice feature Chasing Pain Diagnosing and Treating Trigeminal Neuralgia in General Dentistry by Steven Olmos, DDS, DABCP, DABCDSM, DABDSM, DAAPM, FAAOP, FAACP, FICCMO, FADI, FIAO As dentists, we know quite a bit about tooth and gum pain, but when it comes to chronic facial pain and neuropathic pain, our dental school education leaves us unprepared. The objective of this article is to explain the differences between men and women with chronic orofacial pain and the relationship to proper functional breathing, using a case study as demonstration. 34 JANUARY 2016 // dentaltown.com general practice feature the United States, nearly half research published in Chest 2015 demonstrates that of all adults lived with chronic respiratory-effort-related arousal may be the most pain in 2011. Of 353,000 adults likely cause (nasal obstruction or mouth breath- 11 aged 18 years or older who were ing). Rising C02 (hypercapnia) in a patient with a surveyed by Gallup-Health- sleep-breathing disorder (including mouth breath- ways, 47 percent reported having at least one of ing) specifically stimulates the superficial masseter three types of chronic pain: neck or back pain, muscles to contract.12 knee or leg pain, or recurring pain.2 Identifying the structural area of obstruction A study published in The Journal of the Amer- (Four Points of Obstruction; Fig. 1) of the air- ican Dental Association October 2015 stated: way will insure the most effective treatment for a “One in six patients visiting a general dentist had sleep-breathing disorder and effectively reduce the experienced orofacial pain during the last year. facial muscle contraction, which in turn will result Pain in the muscles and temporomandibular joints in reduction of facial-pain complaints and nerve was reported as frequently as that in the teeth and entrapments (trigeminal neuralgia). It will also surrounding tissues in patients visiting general insure proper swallowing and tongue posture that dentists.” will result in reduced orthodontic relapse (anterior The practical implications for this study were and lateral open bite).13 as follows: “Although the dental curriculum is concentrated on the diagnosis and management Trigeminal neuralgia of pain and related conditions from teeth and Classical trigeminal neuralgia (TN) is a dis- surrounding tissues, it is imperative to include the ease of severe, stabbing neuropathic facial pain of training for other types of orofacial pain, partic- the second and third divisions of the trigeminal ularly those from temporomandibular joint and nerve.14 It is estimated that one in 15,000 people musculoligamentous tissues.”3 suffers from trigeminal neuralgia; however, num- Pain in the orofacial regions affects 21.7 per- bers may be significantly higher due to frequent cent of the population in the United States and misdiagnosis.15 The incidence is greatest in people costs more than $32 billion each year.4 more than 50 years of age, and in women more Patients over the age of 45 and women have frequently than men.16 the highest prevalence of facial pain. Women have It has also been reported that 26 percent of the higher incidence for musculoskeletal pain.5 Hor- American population is at high risk of obstructive mones play a role in chronic pain/TMD, as tes- sleep apnea (OSA), a sleep breathing disorder tosterone reduces pain transmission6 and estrogen (SBD), indicating as many as one in four Ameri- exacerbates pain in the face and jaw.7 cans could benefit from an evaluation for OSA.17 An established relationship exists between In the same report, 57 percent of obese individuals OSA and TMD.8, 9 Two studies tested the hypoth- were at high risk for OSA. Obesity is defined as a esis that OSA signs and symptoms were associated BMI (body mass index) of 30 or greater. with TMD: the OPPERA prospective cohort This case study seeks to demonstrate a long- by Steven Olmos, DDS, DABCP, DABCDSM, DABDSM, DAAPM, FAAOP, FAACP, FICCMO, FADI, FIAO study of adults aged 18–44 years at enrollment (n term cure for trigeminal neuralgia utilizing = 2,604) and the OPPERA case-control study of low-level laser therapy and treatment for nasal chronic TMD (n = 1,716). Both studies supported obstruction. a significant association between OSA symptoms This case demonstrates relief of chronic facial and TMD, with prospective cohort evidence pain of the mandibular division of the trigeminal finding that OSA symptoms preceded first-onset nerve as it innervates the muscles of mastication of TMD: patients with two or more signs and/or (Fig. 2; see p. 36). symptoms of OSA had a 73 percent greater inci- Trigeminal neuropathy can have many ori- dence of first-onset TMD. gins, such as a neoplastic growth compressing the So breathing and facial pain/TMD are linked nerve as it leaves the pons and before it leaves the by sleep bruxism (SB), as the method of chronic cranium through either the foramen rotundum irritation to the joint structures and facial mus- (maxillary division, blue arrow) or foramen ovale cles. SB has been linked to maintaining airway (mandibular division, green arrow) (Fig. 3; see p. 10 patency in OSA, however the most recent 36). Tumors, usually posterior fossa meningioma dentaltown.com \\ JANUARY 2016 35 general practice feature or neuromas, are found in 2 percent of individual drug has been reached it patients who present with typical TGN.18 is lowered and an additional drug is Surgical excision is indicated for these combined until maximum dosage is conditions as diagnosed via MRI. reached and a third drug or new combi- Another source of trigeminal neu- nation is tried. Commonly used drugs ralgia can be enlargement of the middle are Tegretol (carbamazepine), Neurontin meningeal artery that can compress the (gabapentin), Lamictal (lamotrigine), mandibular division as it leaves the skull Klonopin (clonazepam), Baclofen, and Fig. 1 through the foramen ovale. Lyrica (pregabalin). The middle meningeal artery is a The clinical efficacy of low-level laser branch of the maxillary artery in the therapy (LLT) in the treatment of neu- infratemporal fossa. It enters the skull ropathic pain is well established in many through the foramen spinosum (yellow studies.22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32 This is a arrow, Fig. 3), and is within the dura very important tool for the treatment of mater lining the cranial cavity. The crit- nerve injuries, as all other treatments are ical abnormality is vascular contact at palliative, while the laser therapy is truly the dorsal root entry zone, rather than therapeutic. more distally; such is seen in 3 percent to 12 percent of trigeminal nerves at Case study autopsy.19, 20 Brain surgery (microvascular Craig, a 66-year-old man, was decompression) is necessary to treat this referred to our office by an oral maxillo- condition. facial surgeon for the relief of left man- Fig. 2 The most common source of trigem- dibular episodic facial pain neuralgia. His inal neuralgia is peripheral entrapment chief complaints were chronic pain (four of the nerve by the muscles it innervates, years) when chewing, jaw and facial pain. or mechanical trauma (injury). There is He had spontaneous shooting pain on damage to the myelin sheath that lowers the left side of his face. He said he could the capacitance of the nerve that lowers its relate it to a Novocain injection and a threshold for conduction. There is a spon- tooth implant. He was currently being taneous transmission of pain in a sensory treated with carbamazepine 100mg four nerve by contractions of the muscles it times daily, but the pain was not con- innervates or a structure that it passes trolled. He had previously been treated Fig. 3 through. It has been my experience that with gabapentin 300mg three times per mandibular trigeminal neuralgia is often day until it became ineffective. He some- present in combination with a movement times took alcohol and sedatives for pain disorder termed bruxism. Bruxism is an relief or sleeping. exacerbation of normal rhythmic masti- Positive findings from his health catory muscle activity that results in wear history were high blood pressure, stroke, of dentition and muscle-pain disorders. asthma, hepatitis, and frequent wakening The brain is stimulated by a variety of at night. factors, including pain, medications and Our clinical findings at the time sleep-related breathing disorders.21 of examination were: BMI 31.07, B.P. Treatment for trigeminal neuralgia 166/100, pulse 64, respiration 16, tem- is usually medicinal. Membrane-stabi- perature 98.2°. Orthopedic mandibular lizing drugs, anticonvulsants, centrally ranges of motion were 56mm without acting muscle relaxants—individually pain, left and right lateral movements of or in combination—are used. Doses are 10mm, and 9mm of protrusion. Dental increased over time as tolerance and examination demonstrated molar Class metabolism of the drugs increase and I occlusion, with 4mm of overjet and their effectiveness decreases. overbite, with worn dentition (bruxism, Fig. 4 When maximum dosage for each see Fig. 4). Continued on p. 38 36 JANUARY 2016 // dentaltown.com general practice feature Continued from p. 36 Oral evaluation demonstrated Mal- evaluation and treatment of nasal lampati Class IV, furrowed tongue, obstructions. coating of the tongue (indicating mouth breathing from nasal obstruction), and Treatment results scalloping of the tongue, which are both At four weeks of the combined treat- indicative of a sleep-related breathing dis- ment of decompression, carbamazepine order (Figs. 5 & 6). and weekly applications with the Mphi Fig. 5 There were no positive findings for laser, the facial pain and jaw pain had muscle, tendon and ligament palpation. resolved, and the pain when chewing Imaging utilizing CBCT (cone-beam had reduced between 40 percent to 50 computed tomography) demonstrated percent. a significant cant of the mandible to the The unique synergistic use of two left side (affected side) and was confirmed wavelengths of energy (808 and 905), with a photograph of the patient with a using both pulsed and continuous tongue blade (Figs.