Occlusion is the dental term for contact between the maxillary, or top, and mandibular, or bottom, teeth. Occlusion occurs either dynamically, when the teeth are approaching each other during eating or talking, and statically, when the jaw is at rest. Occlusal trauma is damage that befalls the teeth, usually due to excessive force, and causes them to align improperly. Dental treatments, diseases, and trauma can all cause the biting surfaces of the teeth to change, thereby altering occlusion. When these changes are negative, they may cause tenderness or pain, and they may damage or move the teeth; in these cases, occlusion is called traumatic occlusion.
While occlusal trauma may be diagnosed based on evident symptoms, there are many microscopic features that may also occur due to occlusal trauma. These include hemorrhage, necrosis, bone resorption, loss of and tears in the cementum, and widening of the periodontal ligament. Diagnosis and treatment include categorization as either primary or secondary occlusal trauma. Primary occlusal trauma arises when force that is greater than normal is exerted on the teeth. This may involve bruxism, which is the clenching or grinding of the teeth, or it may involve other habitual functions like chewing on fingernails or pencils. Forces may be excessive in their duration, their frequency, or their magnitude. Primary occlusal trauma is also characterized by the absence of periodontal disease. Secondary occlusal trauma occurs when the teeth experience normal or excessive occlusal forces and the teeth are already compromised by periodontitis.
Treatment for primary occlusal trauma must first involve the elimination of the cause. In many cases, with these periodontally uninvolved teeth, removal of the cause will eliminate any mobility of the tooth. This treatment may involve mechanical readjustment of the height of an affected tooth; for example, if a cavity has recently been restored but the height of the restoration was not sufficiently sculpted, a return visit to the dentist for modification of the restoration can restore the bite to its healthy, functional state. When the cause of primary occlusal trauma is parafunctional habits, treatment may involve training patients to eliminate these detrimental habits. For people with bruxism, this could include the use of a night guard, which aids in preventing the teeth from clenching or grinding during sleep. If excess of force is due to a limited number of teeth compensating for lack, therefore doing the work of several teeth, a dental bridge or other restoration may be recommended to help rebalance the distribution of force more evenly.
Secondary occlusal trauma is treated by the same first measures as primary occlusal trauma, but, because the teeth are periodontally involved, additional treatment is also necessary. This may include splinting the teeth to discourage mobility while also managing the cause of the mobility, which is usually loss of bone and periodontal tissue. These causes of mobility must be treated with surgical measures, and dental restorations can then be placed. Dental restorations may include removable prosthetic devices or implant-supported restorations; when possible, implant-supported restorations may be preferable, as they invigorate and restore the bone that supports the teeth and may therefore prevent future occlusal trauma.