Abstract
Although the intercuspal position has generally been used as the reference jaw position in which final prostheses are inserted, this is merely based on the understanding that the intercuspal position is always functionally and morphologically normal. Kawamura described 3 factors, which are the masticatory muscles, temporomandibular joint, and teeth, and the nerves innervating the masticatory muscles, as the functional occlusal system, and explained the importance of the harmonized functioning of these factors. The intercuspal position is the most stable jaw position in which the maxillo-mandibular teeth are occluded with a maximal contact area, and the positional relationship between the condyle in the mandibular fossa and the articular disc is stable, and must be harmonized with the neuro-muscular organization. Furthermore,it is more desirable that the deviation from the centric position be slight. However, when tooth inclination, movement, and defects develop due to dental caries, severe tooth abrasion, and periodontal disease, its normal intercuspal position gradually collapses and becomes unstable,causing muscular hypertension. Furthermore, when clinicians perform symptomatic treatment-like prosthetic treatment, believing that the mandibular position is in the process of collapse, functional abnormalities in the stomatognathic system and of the entire body may occur. Therefore, observing long-term occlusal conditions using provisional restoration based on a diagnostic wax-up in the centric position, final prostheses should be inserted after confirming that there is no problem regarding the achieved mandibular position. Furthermore, it is considered that evaluation of the validity of occlusal treatment from its long-term clinical course becomes important.
