Occlusion and your Bite
by Supriya Verma, DMD, FAGD
- Occlusion, means simply the contact between teeth when the patient brings their jaws together. More technically, it is the relationship between the maxillary (upper) and mandibular (lower) teeth when they approach each other, as occurs during chewing or at rest.
- Malocclusion is the misalignment of teeth and jaws, or more simply, a "bad bite". Malocclusion can cause number of health and dental problems.
- Static occlusion refers to contact between teeth when the jaw is closed and stationary, while dynamic occlusion refers to occlusal contacts made when the jaw is moving, as with chewing.
- Centric occlusion is the occlusion of opposing teeth when the mandible is in centric relation. Centric occlusion is the first tooth contact and may or may not coincide with maximum intercuspation. It is also referred to as a person's habitual bite, bite of convenience, or intercuspation position (ICP). Centric relation, not to be confused with centric occlusion, is a relationship between the upper and lower jaw.
- Malocclusion can cause a number of problems, not just with teeth, but with the supporting bone and surrounding soft (gum) tissue, the temporomandibular joint (TMJ), and jaw muscles. Teeth, fillings, and crowns may wear, break, or loosen, and teeth may be tender or ache. Receding gums can be exacerbated by a faulty bite. TMJ problems, broadly termed temporomandibular joint disorder or TMJ syndrome, can include clicking, grinding, or pain in the jaw joint, ringing or buzzing in the ears, and difficulty opening and closing the mouth. If the jaw is malpositioned, jaw muscles may have to work harder, which can lead to fatigue and or muscle spasms. This in turn can lead to headaches or migraines, eye or sinus pain, and pain in the neck, shoulder, or even back. Untreated damaging malocclusion can lead to occlusal trauma which can lead to loosening of the teeth, excessive wear of the teeth and drifting of the teeth into new positions.
- Some of the treatments for different occlusal problems include tooth adjustments, replacement of teeth, medication (usually temporary), a diet of softer foods, and relaxation therapy for stress-related clenching. Fixed appliances, known as orthodontics or dental braces, may be used to adjust the occlusion, and removable appliances, called occlusal splints, may be used to alleviate pain in the TMJ, prevent further damage and wear of the teeth and supporting structures.
- But how does the mouth work from an occlusion standpoint? The anterior teeth protect the posterior teeth by providing for a plane of guidance during excursions, thus allowing the cusps of the posterior teeth to disclude rather than strike one another during lateral or protrusive movements from centric relation. In other words, the posterior teeth have much larger crowns and many more cusps than the anterior teeth. Because posterior crowns are so much wider and possess cuspal projections in various configurations, the cusps of the maxillary teeth and those of the mandibular teeth have an opportunity to bang into each other during chewing, speech or simply meeting together when one bites down. To prevent this from happening, the anterior teeth of each arch will, ideally, be situated so as to come into contact before the cusps of the posterior teeth do, thus averting such a situation.
- The posterior teeth protect the anterior teeth by providing a stable vertical dimension of occlusion. While anterior teeth may retain their natural position even after loss of posterior teeth, the masticatory forces will eventually cause the single-rooted anterior to splay, thus leading to a collapsed bite.
- Occlusal splints (also called bite splints, bite planes, or night guards) are removable dental appliances carefully molded to custom fit the upper or lower arches of teeth of a patient.
- They are used to protect teeth/implants and restoration surfaces, manage mandibular (jaw) dysfunction, and stabilize occlusion or create space prior to restoration procedures. Patients prone to nocturnal bruxism (nighttime clenching or grinding), should routinely wear occlusal splints at night to take stress of the TMJ and its a associated muscles and prevent damage to the teeth/implants and associated bone and soft (gum) tissue.
- The splint generally covers all the teeth of the upper or lower arch, but partial coverage is sometimes used. Occlusal splints are usually used on either the upper or the lower teeth, termed maxillary splints or mandibular splints respectively. We favor mandibular (lower) splints as they are less likely to interfere with speech and can be worn during the day without being obvious like a maxillary (upper) splint.
- Pankey-type occlusal splints are “flat-plane” with a flat surface against the opposing teeth, and help jaw muscle relaxation, while repositioning occlusal splints are used to reposition the jaw to improve occlusion. These are used when chronic pain in the joint is present and allows the joints to find a comfortable position. These may be used early in full mouth construction also to determine the best position to restore the mouth to.
- Tanner-type occlusal splints have depressions in the surface that the opposing teeth contact providing positive contacts. These type splints are used for patients who are showing wear of the teeth or damage to the supporting bone and soft tissue. Additionally, they are used to protect teeth and implants in those patients who clench their teeth and may be of benefit to those who exercise as most patient’s clench during exercise.
- Pankey splint -The Pankey Splint is a flat plane splint made from a tooth colored acrylic resin material. The occlusal scheme is created with one point occlusal contact per posterior tooth, combined with anterior and cuspid guidance. This allows for total posterior disclusion in all excursions. The Pankey splint is used in patients with: acute pain in the temporomandibular joint (TMJ), chronic issues with the TMJ and when the dentist is trying to determine where the joint and teeth need to be have the joint in Centric Relation (CR) to allow a starting point for restoration of the mouth. This is basically a deprogrammer appliance as there is no locked position for the posterior cusps so the joint will settle into a comfortable position without moving into the habitual positions. Typically this type appliance is worn 24/7 except when eating to allow the joint to become deprogrammed. Occlusal adjustments are made every few days after initial insertion to maintain the even point contacts then this moves to weekly then biweekly until a stable position is achieved.