Occlusion: the standard of care.

Journal of the Canadian Dental Association " A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up familiar with it. " — Max Planck (German physicist 1858-1947) A s a group, dentists are the specialists of occlusion. We are responsible for the physiological harmony of the temporomandibular joints, masticatory musculature and teeth. Nobody can seriously debate that occlusion does not have an intimate relationship with the joints and muscles. 1 Occlusion is within the adaptive capacity of the joints and muscles to accommodate, or it is not. When it is not, physiological distress results, which inevitably leads to pain and dysfunction. 2 Are we doing our best to ensure that our specialty, occlu-sion, is providing physiologic harmony amongst teeth, muscle and bone? The short answer is no. Optimistically speaking, however, the standard of care is rising. Subgroups of our profession — the International Association of Orthodontists, the American Association of Functional Orthodontists and the International College of Cranio-Mandibular Orthopedics — are at the forefront of this progress. The ramifications of this science are not limited to orthodontics. Facts support the view that the method taught to find " centric relation " was wrong. The retruded, uppermost position of the condyles impinges on the delicate retrodiscal tissues, encourages the meniscus to subluxate and is not in its most effective position for load stress against the powerful muscles of mastication. Healthy joints function in a " down and forward " position known as the Gelb 4/7 position. 3 On radiograph, patients having temporomandibular dysfunction (TMD) most often have condyles displaced up and back, compressing neural and vascular tissues and thus activating nociceptors. It is the occlusion that " locks " the mandible in a retruded position as the proprioceptive afferent stimuli from periodontal ligaments affect muscle posture. 4 Muscle soreness and trigger point formation with referral pain patterns result. 5 Until recently, we have not even been able to locate the true resting position of the mandible devoid of muscle posturing interference. As specialists in occlusion, we should be able to. Surface electromyography (myotronics, bioresearch) clearly shows the elevated muscle activity that results from malocclu-sion-directed nociception. It also clearly shows normal resting levels after surface transcutaneous electrical nerve stimulation (TENS). Computerized saggital mandibular kinesiology graphically demonstrates habitual centric occlusal position, the true …