A growing number of dentists are now providing botulinum toxin, otherwise known as BoNT-A (Botox®), treatment for their patients for both oral and maxillofacial cosmetic and therapeutic use. It has been estimated that up to 16% of North American dentists now use BoNT-A in their practices for cosmetic and therapeutic uses . While the use of BoNT-A for cosmetic purposes has gotten a lot of attention in a number of dental journal articles, BoNT-A products are excellent products to use for dental therapeutic uses in a number of areas.
BoNT-A works by inhibiting the release of acetylcholine at the neuromuscular junction. Acetylcholine, as you well may remember, depolarizes the motor end plate of the muscle and will cause a muscle contraction. By inhibiting the release of acetylcholine, BoNT-A effectively will either reduce the intensity of the contraction of the muscle or will eliminate the contraction altogether, depending on the dosage used. Essentially, BoNT-A neurotoxin interrupts the contraction process of the muscles and causes a temporary muscle paralysis. This can last usually anywhere up to three months as the muscle initiates new acetylcholine receptors and the growth of branches from the neurons to form new synaptic contacts. Gradually the muscle returns to its full function and with no side effects whatsoever.
When you think about this clearly, and when one learns how to use BoNT-A neurotoxin properly, it can be used for a number of dental therapeutic procedures that can relieve pain and can retrain muscles which can certainly enhance dental treatment plans as well as help some serious disorders that have been frustrating to the dental practitioner for many years.
TEMPOROMANDIBULAR JOINT DISORDER (TMD) AND BOTOX
I have personally treated patients for temporomandibular joint disorder in my practice for the past 30 years. It almost seems as if temporomandibular joint disorder is some kind of fad in dentistry that has gone in and out of style during my career. We have been told that 80% of patients have some sort of TMD and need treatment, then it is something that you just don’t hear about for a while. TMD is almost like a black box that sits somewhere in the middle of medical and dental healthcare professionals with neither profession having a decent treatment plan for relieving its symptoms. Often, TMD is just a clinical label for any pain of the jaw and facial muscles, which can be associated with headaches, earaches, cervical spine disorders, and general facial pain.
Often, with TMD cases, there may be one or multiple trigger points in muscles that a patient points to. Palpating these areas immediately sends a cascading pain along muscle or neuronal tracks that radiate from the trigger point outward. Many agents have been used and injected directly into these trigger points to treat these areas, including sterile saline and local anesthetic. The theory of trigger point injections is that the disruption of the trigger point may be enough to bring some relief, either short term or long term. The success of these treatments have been limited, primarily because the effect of sterile saline or local anesthetic lasts from a few minutes to a few hours.
Other treatments have been used for TMD disorders over the years which include psychological therapy, maxillary or mandibular repositioning,
orthotic devices, neuromuscular therapy, drug treatments such as anti-inflammatory agents, non-narcotic and narcotic pain medications, muscle relaxants, chiropractic therapy, massage, acupuncture, and even antidepressants.
There are many schools of thought in dentistry that an orthognathic approach will work the best with occlusal equilibrations and full mouth reconstructions, which will absolutely relieve facial pain. The use of BoNT-A therapy for TMD symptoms has been in use for many years. For trigger point injections, it makes much more sense to use BoNT-A products because the effects will last for three months and you are actually helping relieve the intensity of the contraction of the muscle, which is usually in spasm.
Many times we, as dentists, have developed tunnel vision and believe that just by fixing the dentition that it will solve all of the other problems. Many dentists completely ignore the fact that the muscles themselves may be in spasms and need the relief in order to allow us to achieve the right occlusal equilibration and end-point for our full mouth reconstruction. In other words, what I would like you to think about is this progression – let’s treat the muscle spasm symptoms first and then build our occlusion to the relieved muscles so that the facial pain will be eliminated. Studies clearly show the relief of painful symptoms in facial muscles with BoNT-A of up to 90% of patients who had not responded to traditional treatments .
For facial pain and TMD cases, BoNT-A neurotoxins can be generally applied to a number of muscles of facial expression and mastication, including the masseter, temporalis, frontalis, procerus, corrugator, orbicularis oris, orbicularis oculi, mentalis, depressor anguli oris and pterygoid muscles.
The use of BoNT-A products in TMD therapy can give us a totally new insight as to helping these patients who have had a lot of trouble getting relief before.
Bruxism is the general term that refers to both clenching and grinding of the teeth. There have been numerous theories as to why this occurs and certainly most bruxism will manifest itself nocturnally. Certainly, there are components of psychological stress that may cause it. No matter what the theory is that causes bruxism, there is no question that it leads to the destruction of otherwise healthy dentition, exacerbates periodontal disease, either causes TMD and is the cause of headaches and facial pain. Traditionally, intraoral appliances have been the treatment of choice for bruxism with good success as to relieving some or all of the symptoms.
We use BoNT-A products routinely in helping patients with bruxism. Here is where proper training in the use of BoNT-A neurotoxins is really essential. We would typically treat bruxism and TMD patients with bilateral injections of BoNT-A into the masseter and temporalis muscles. A practicing clinician must have a good feel as to what the proper dosage is because too much of the BoNT-A will paralyze the muscles of mastication and interfere with the patient’s ability and confidence in chewing and talking. Too small of a dosage will not have any effect at all. Using the right amount of BoNT-A will reduce the intensity of contractions of these muscles of mastication as well as give your patient full competence for chewing, eating properly, and speaking. The relief afforded to patients by BoNT-A neurotoxins can help eliminate facial pain, grossly reduce their TMD symptoms and can significantly help the other associated treatments of periodontal disease by removing the bruxism element.
As an example of BoNT-A treatment for both TMJ and bruxism, figure 1 shows a patient who has experienced facial pain and has significant bruxism, so much so that she has had to have significant dentistry repeated because of restoration breakage. You can see just be looking at this patient that her masseter muscles are in spasm even at rest and gives her a very square look to her face. This is not skeletal but is purely a result of masseter hypertrophy. Figure 2 is a close up view of the masseter muscle in spasm. You can see the result of BoNT-A therapy two weeks later in figure 3 – the masseter muscles are no longer in spasm and the patient’s face is much more rounded at the corners of the mandible. We were not interested in the cosmetic effects of this treatment even though the patient was thrilled. Her facial pain had disappeared and she subsequently has had successful long term dental treatment with BoNT-A injections repeated approximately every 4-6 months to maintain her comfort.
While the role of the facial muscles in determining placement of the teeth is fairly well known, many times it seems that dental practitioners forget about the muscles once the teeth are set after orthodontic therapy has taken place. Relapse has been a continual problem for many general and orthodontic dental practitioners and there are a number of theories as to why this happens. There are so many patients where you can see on their faces just by gross observation that they have a hyperactive mentalis muscle that may be disrupting the alignment of the teeth. Other muscles in spasm can usually be observed as well with proper training.
When you look back at some of the previous paragraphs of this article and you come to the realization that BoNT-A neurotoxins can go ahead and reduce the muscle contraction intensity, over time it is very possible that muscles can be trained to work normally. Anyone who has treated the muscles of facial expression for cosmetic purposes with BoNT-A sees this routinely where the cosmetic results will last for longer periods of time for patients who have kept up a schedule of receiving BoNT-A neurotoxins on a regular basis. This idea could revolutionize how we deal with orthodontic relapse as dental practitioners become more familiar with the use of BoNT-A neurotoxins.
The same idea described in the previous paragraph directly can be applied to those patients who have trouble getting used to removable prosthodontics in their mouths. While it is true that more and more patients everyday are receiving implant treatment to help stabilize dentures, there will always be patients who can either not afford implant therapy or because of underlying challenges such as medical history or bone resorption, just are not candidates for implant therapy. Many of these patients have hyperactive muscles, which then creates a huge challenge of having them retain the dentures in their mouths. If you study the facial muscles carefully in patients, you will often times see a hypertrophic masseter and can even feel strong lateral and medial pterygoid muscles that cause this situation. Muscle training via BoNT-A neurotoxins may someday provide relief as dentists become more familiar with their use.
The use of BoNT-A in the oral and maxillofacial areas is really nothing new and one can even find literature dating back almost two decades in this arena . As dentists are now accepting and treating patients with these products for soft tissue cosmetic use to enhance the dental esthetics, BoNT-A neurotoxins are getting much more attention in dentistry than ever before. Certainly, if dentists are going to use these therapies, training is absolutely essential and required both ethically and by state dental boards. Research has certainly shown that BoNT-A products, such as Botox® and Dysport®, is a viable treatment for many facial, TMD, and oral dysfunctions, when they are based in the musculature.
BoNT-A products are a conservative, minimally invasive, and relatively painless therapeutic approaches to dental, facial, and head and neck areas that have frustrated many dentists over the past 30 years. The safety of these products is well known because of their temporary nature and the fact that they are totally reversible over time with generally no lasting effects. The other advantages are that it gives the patient and the dental practitioner the option to stop a therapy at any time and return to the previous state with no ill effects.
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