Headache is a common medical complaint and is generally categorized by 1 of 3 syndromes, (i) migraine headache, (ii) tension-type headache, and (iii) cluster headache. Migraine is characterizedby attacks of headache, nausea, vomiting, photophobia, phonophobia, and malaise. Tension-type headache is mild-to-moderate in intensity, bilateral, and non-throbbing without other associated features. Cluster headache is strictly unilateral, begins quickly without warning, and reaches maximal intensity within a few minutes. It is usually deep, excruciating, continuous, and explosive in quality, although occasionally it may be pulsatile and throbbing. Other headache syndromes may include sinus headache, post-traumatic headache, medication over-use, and temporomandibular joint (TMJ) dysfunction. The typical headache associated with TMJ presents as unilateral ear or pre-auricular pain that radiates to the jaw, temple, or neck. The pain is deep, dull, continuous, and usually worse in the morning. It is typically associated with a limitation of jaw motion and deviation of the jaw upon opening. Physical examination may reveal tenderness of the muscles of mastication and, less commonly, clicking of the joint. Many cases are difficult to distinguish from tension type headaches (Bajwa and Sabahat, 2008).
Pharmacological treatment of headaches is aimed at reversing, aborting, or reducing pain and the accompanying symptoms of an attack, and to optimize the patient's ability to function normally. Most attacks of mild migraine can be effectively treated by anti-emetics followed by analgesics such as aspirin, acetaminophen or non-steroidal anti-inflammatory drugs (NSAIDs). Moderate-to-severe attacks are successfully treated utilizing combinations of ergotamine tartrate, dihydroergotamine, and triptans with anti-emetics, simple analgesics, NSAIDs, and/or opiates. For severe migraine headaches, alternative medications include intravenous administration of neuroleptics such as chlorpromazine (Thorazine) and prochlorperazine (Compazine), occasionally corticosteroids such as prednisone, hydrocortisone, dexamethasone, and methylprednisone, and lastly parenteral narcotic analgesics such as meperidine and the nasal spray butorphanol tartrate (Stadol NS). The acute or abortive therapy of tension-type headache (TTH) ranges from non-pharmacologic therapies to analgesic medications. The treatment of headache due to TMJ primarily involves therapy of the joint disorder itself. Most cases can be treated with local heat, physical therapy, dental hygiene, NSAIDs, and dietary measures (Bajwa and Sabahat, 2008).
Complimentary and alternative therapies for headaches include acupuncture, aromatherapy, biofeedback, Bowen technique (remedial therapy tool to manage pain), chiropractic, cranial electrical stimulation, hyperbaric oxygen therapy, hypnotherapy, massage, nutrition, reflexology, Reiki, spinal/osteopathic manipulation, transcranial magnetic stimulation, and yoga although the effectiveness of many of these approaches has not been established. Recently, it has been suggested that intra-oral dental appliances that are used to reduce the intensity and the amount of jaw muscle activity may be beneficial in preventing headaches.
Advocates of intra-oral appliances for preventing headaches believe that stimulation of the trigeminal nerve through increased cervical as well as mandibular muscle activities (e.g., clenching or grinding the teeth), which can occur when the patient is awake or asleep, may trigger headaches. Intra-oral appliances are thought to aid in controlling clenching and grinding of the teeth, thus, decreasing the possibility of over-stimulating the trigeminal nerve system. These intra-oral dental appliances are pre-fabricated in different configurations covering all or some of either the upper or lower dentition.
An example of an intra-oral device for the prevention of headaches is the Nociceptive Trigeminal Inhibition - tension suppression system (NTI-tss, NTI-TSS, Inc., Mishawaka, IN). It was developed and patented by James P. Boyd, DDS. While the Standard NTI-tss device can be worn indefinitely (while sleeping), the NTI-tss Daytime device is recommended for patients with migraine (in addition to the use of the Standard device) for 4 to 8 weeks during waking hours. The inch-wide device is made of clear plastic and fits over 2 front teeth -- usually but not always the top teeth. It keeps the back teeth from coming together and thus prevents clenching. The NTI-tss is sold in a kit form, and dentists can mold and custom-fit the device to patients’ teeth in approximately 1 hour.
The NTI-tss was cleared by the Food and Drug Administration (FDA) through 510(k) premarket notification in June 2001 for the prevention of medically diagnosed migraine headaches as well as migraine associated with tension-type headaches, and for the prevention of bruxism and TMJ. Thus, the manufacturer was not required to submit to the FDA the evidence of efficacy that is necessary to support a premarket approval application (PMA).
Staplemann and Turk (2011) has commented that, since its FDA clearance, controversy has persisted concerning the therapeutic benefits and potential dangers of use of NTI-tss. Staplemann and Turk (2011) state that the manufacturer recommends that the appliance be utilized for the treatment of bruxism, temporomandibular disorders and headaches. The authors stated that articles in both the lay press and the dental literature have reported the positive effects associated with the use of the NTI-tss device. The authors note that other researchers, however, have raised doubts about the appliance; warning of the potential for adverse events such as appliance aspiration, ingestion and permanent occlusal changes after prolonged and unmonitored use.
Lamey et al (1996) studied the relationship between the nocturnal wearing of an acrylic appliance of 2 mm thickness covering all occlusal surfaces of the teeth (2 appliance designs) and the frequency of migraine attacks in 19 patients who had migraine with or without aura. One design covered the maxillary occlusal surfaces of the dentition while the other design contacted the palatal mucosa only and was free of the occlusion. Treatment outcome was expressed as the number of migraine attacks per week per patient. The occlusal cover appliance reduced the number of attacks on average to about 40 % of that normally experienced. The improvement was most marked in those who had frequent migraine attacks (i.e., 2 attacks per week on a regular basis). The authors concluded that acrylic appliance therapy is of value in migraine sufferers who have attacks on waking but the appliance design has to involve covering of the occlusal surfaces of all of the teeth (Note: the NTI-tss only covers the front 2 teeth). The drawbacks of this study were that it was a non-randomized study with a small sample size and no long-term follow-up.
Two studies comparing the NTI-tss splint with a standard stabilization splint in the treatment of TMJ have been published (Magnusson et al, 2004; Jokstad et al, 2005). Results obtained by Magnusson favored the use of a stabilization splint over the NTI splint. In addition, 1 subject treated with the NTI-tss splint exhibited an impaired occlusion at the 6-month follow-up. Jokstad found no differences between a standard stabilization splint versus the NTI splint regarding TMJ treatment efficacy over a 3-month period. Both comparative studies were small and neither focused on migraine as an outcome measure. Further studies are needed to determine the effects of the NTI-tss splint on the treatment of headaches, including migraine, as well as possible long-term side effects.
Stapelmann and Turp (2008) conducted a systematic review to evaluate the currently available evidence regarding the efficacy and safety of the NTI-tss splint. The authors found that 9 of 68 relevant publications reported about the results of five different randomized controlled trials (RCTs). Two RCTs concentrated on electromyographic (EMG) investigations in patients with temporomandibular disorders (TMDs) and concomitant bruxism (citing Baad-Hansen, et al., 2007) or with bruxism alone (citing an unpublished PhD thesis by Kavakli, 2006). The authors stated that, in both of these studies, compared to an occlusal stabilization splint the NTI-tss device showed significant reduction of EMG activity. The authors stated that 2 RCTs focused exclusively on TMD patients; in one trial (citing Magnusson, et al., 2004), a stabilization appliance led to greater improvement than an NTI-tss device, while in the other study (citing Jokstad, et al., 2005) no difference was found. The authors identified one RCT evaluating the use of the NTI-tss device in headache and migraine (citing Shankland, 2002); in this study, patients with tension-type headache or migraine responded more favorably to the NTI-tss splint than to a bleaching tray. NTI-tss-induced complications related predominantly to single teeth or to the occlusion. The authors concluded that the evidence from RCTs suggests that the NTI-tss device may be successfully used for the management of bruxism and TMDs. The authors noted, however, in order to avoid potential unwanted effects, the device should be chosen only if certain a patient will be compliant with follow-up appointments. The authors stated that the NTI-tss bite splint may be justified when a reduction of jaw closer muscle activity (e.g., jaw clenching or tooth grinding) is desired, or as an emergency device in patients with acute temporomandibular pain and, possibly, restricted jaw opening. Commenting on the systematic evidence review by Stapelmann and Turp, Bender (2011) stated that the inability to design a double blind study involving intra-oral appliances creates limitations to the quality of the findings. Differing inclusion criteria, small sample sizes and the lack of standardized diagnostic criteria also limited the quality of the included evidence. Bender (2011) also noted that the literature is not conclusive as to the role of EMG activity and its relevance to pain.
UpToDate reviews on “Overview of chronic daily headache” (Garza and Schwedt, 2013a), “Chronic migraine” (Garza and Schwedt, 2013b), “Tension-type headache in adults: Preventive treatment” (Taylor, 2013), and “Trigeminal neuralgia” (Bajwa et al, 2013) do not mention the use of intra-oral appliances as therapeutic options.
There is insufficient data on the effectiveness of oral appliances in the treatment of headaches. Randomized controlled studies are needed to determine the effectiveness of oral appliances in the treatment of headache.