CHAPTER 11 Occlusion
Your Bite, Temporomandibular Joints, Temporomandibular Dysfunction
Until recent years the area of occlusion in dentistry has not been emphasized. Therefore, many dentists have not been involved with treatment of people with occlusion problems. As a rule, the specialty most involved with movement of teeth to provide acceptable occlusion is orthodontics. Other areas of dentistry, including prosthodontics, periodontics, oral surgery, and general dentistry, are more involved with the condition commonly called temporomandibular dysfunction (TMD) or temporomandibular joints (TMJ) in the lay literature.
Currently, TMD is used most often to describe the syndrome (or disease), while TMJ is used to describe the anatomy of the specific location. This chapter is primarily concerned with TMD, whereas moving of teeth into proper function and appearance is included in the chapter on orthodontics (p. 99).
Your skeletal size is partially formed before your teeth erupt. As the primary (baby) teeth or permanent teeth erupt into the mouth one by one, the upper and lower teeth occlude (come together) in a haphazard way in direct relation to tooth size, size of the upper and lower jaws, relation of the jaw joints in the head, relation of jaws to one another, health of the patient, any oral habits, and numerous other factors. If all the factors are related in the manner that nature intended, the teeth will occlude (come together) correctly. If one or more of the factors is incorrect, malocclusion (incorrect bite) may be present, teeth may appear crooked and irregular, and the bite will be abnormal.
Other factors may cause a poor bite, including mixed genetics of various races; improper development of the jawbones; accidental trauma to the mouth; dental fillings, bridges and dentures; diseases such as arthritis; and other conditions.
Does a poor bite automatically stimulate a jaw dysfunction, pain, and jaw joint degeneration? No. However, one of the conditions that has been associated with TMD is a malaligned bite. This subject deserves an entire chapter because it has caused significant distress among patients, continual discussion by the lay press, and, most importantly, confusion among patients and all categories of health practitioners. Because some dentists do not treat occlusion, you may want to initiate the discussion of your specific problems with your general dentist. Referrals may be made to another general dentist; a prosthodontist; a periodontist; an oral surgeon; an ear, nose, and throat specialist; a chiropractor; or a physical therapist.
Often, unstimulated pain in the head, neck, and shoulders may be muscle dysfunction related to malaligned occlusion. This syndrome is described as temporomandibular dysfunction (TMD). Innumerable causes are related to head and neck pain, and patients are advised to contact their dentist as soon as possible before making any conclusions, to confirm that the pain they are experiencing may or may not be related to occlusion (bite).
Pain related to occlusion and jaws is most common in the following locations: sides of head (temples), sides of lower jaw (cheeks), lateral sides of neck, back of head, top of shoulders, and upper back. Pain in one or all of these locations may be present at the same time. Usually, head pain (headaches) is not related to the jaws if it is in the eyes, nose, forehead, or top of the head. If pain is present in these locations, you probably do not have a jaw problem. Numerous diagnostic methods may be necessary to confirm that the pain is related to the jaw. Although there are many sophisticated treatment methods for muscle pain (headache) related to occlusion (bite), the simple, more common treatments, listed below, are emphasized in this book.
On movement of your jaw, you may feel or hear a “click” or “pop” on opening, closing, or both. This sound may be loud enough to attract the attention of other people, but it may be slight enough that only you are aware of it. Pain may or may not be associated with the sound. You may stimulate the pop by various movements of your mouth, or by chewing in ways that place stress on your jaw. A click without pain may not be a problem, but a click with pain usually signals that some problem is present. The usual conservative therapy for jaw joint clicking includes one or more of the following treatments:
After months to years of mild jaw dysfunction and/or presence of other conditions such as an accident or arthritis, a grinding (“gravel”) sound in the jaw joints may occur. This condition usually indicates some breakdown of the jaw joints that may or may not have been associated with the occlusion (bite). When this sound occurs, the possibility for successful, simple, conservative treatment is reduced. However, the sequence of therapy for grinding or grating jaw joints varies from relatively simple to complex. Any or all of the following treatments may be used:
Occasionally the bones, ligaments, and muscles that make up the mechanism of the jaw joints become malaligned, and, as a result, the jaw locks open or closed. This can be painful as well as frustrating. Frequently, your dentist can assist the jaw to open with simple manipulations in the dental office, but more often other treatment is required. One or more of the following treatment methods will probably be used:
At least one fourth to one third of the world population grinds their teeth excessively, thereby wearing tooth structure beyond normal expectations (Fig. 11.1). This activity is called bruxism or clenching. During the first years of life this wear usually goes undetected, but soon it is evident, and concern is expressed. In the later stages of this problem, pain or even tooth death is caused by the wear. If you brux or clench your teeth excessively, you have the following potential treatment options, directly related to the severity of the condition as observed by your dentist: