Occlusion, simply means the contact between teeth. 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 can cause a number of problems, not just with teeth, but with gums, the tempromandibular 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 tempomandibular 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. Some of the treatments for different occlusal problems include tooth adjustments (equilibration), replacement of teeth, occlusal splints (nightgaurds), orthodontics ( braces), and in severe cases, full mouth reconstruction.