Abstract
In order to clarify the functional meaning of every part of the occlusal surface, the teeth displacements during clenching and mastication were microscopically measured, especially on the upper and lower first molars which had many possibilities to be restored in the dental treatments. Additionally, the main occluding area and the process of changing the shape of hard food during mastication were macroscopically observed.
Consequently, three elements to realize the form of the functional occlusal surface were led.
1. The occlusal contact to the stabilize intercuspal position
2. The main occluding area between the lingual cusp inner incline of upper molar and the buccal cusp inner incline of lower molar to crush hard food during mastication
3. The overlap of the non-functional cusp to form smoothly swallowable food bolus
To stabilize the intercuspal position by means of the first molar, the buccal cusp of lower molar should firstly interlock the fossa of the upper molar. Secondly, there must be at least one occlusal contact near the top of the cusp so that main force vector may direct to the longitudinal axis of the tooth. Furthermore, as the results of the analysis on occlusal contact patterns at the intercuspal position, it is suggested that above-mentioned occlusal contact is important for the first molars to become the main occluding area during crushing hard food.
