THE CAUSES OF OCCLUSION DISORDER OCCURRENCE (LITERATURE REVIEW)

Occlusion means the contact of teeth in opposing dental arches when the jaws are closed (static occlusal relationships) and during various jaw moments (dynamic occlusal relationships). Recent clinical observations and scientific data have proved the connection of occlusal overloads to periodontal damage. Comparative studies to determine if there is an association between occlusal trauma and periodontitis show that there appears to be a definite link. It has been determined that interleukin-1 beta is produced by human periodontal ligament cells in response to mechanical stress. Interleukin-1 beta is a stimulator of bone resorption and a known key mediator involved in periodontal disease. As a result, we can see the teeth with a combination of functional mobility and widened periodontal ligament spade, local periodontitis is formed. Another reason of occlusal disharmony is tooth wear. It is caused by three phenomena: erosion (dissolution of hard tissue by acidic substances), attraction (wear through tooth-tooth contact) and abrasion (wear produced by interaction between teeth and other materials). A common cause of attritional wear is the bruxism. Bruxism is an oral habit consisting of involuntary rhythmic or spasmodic nonfunctional gnashing, grinding, or clenching of teeth, in other than chewing movements of the mandible. In 1901, Karolyi described occlusal interferences as an important etiological factor in bruxism in combination with psychical influences. He observed that even minor occlusal interferences could be a trigger for grinding habits in neurotic patients. Severe wear is also a common occurrence in postorthodontic patients whose teeth have been held in functional interference for an extended period by a retainer. When teeth are prevented by a retainer from adaptively moving into a nonrestrictive alignment, the wear occurs rapidly and often causes severe damage in a short time. Partial loss of teeth is one of the most common causes of occlusal disease. Among the permanent teeth due to complications of caries, the first molars are lost in the first place. The first molars are the functional center of chewing. Partial loss of teeth leads to displacement of the antagonists and changes of oсclusal contacts. Occlusion is the main precondition of chewing, speaking, swallowing, breathing. It should be physiological and functional, combine static and dynamic occlusal relationships, proper connection between the teeth, temporomandibular joint and masticatory musculature. The design of the restored tooth surface can have important effects on the number and location of occlusal contacts and must take into consideration static and dynamic relationships. Having analyzed the available scientific and medical literature and based on our own clinical experience, a conclusion can be made that the primary link in changes of occlusal relationships is caries disease.