From the point of view of GI bleeding, however, the demarcation between the upper and lower GI tract is the duodenojejunal (DJ) junction (ligament of Treitz); bleeding above the DJ junction is called upper GI bleeding, and that below the DJ junction is called lower GI bleeding.
Answer Wiki. Dental occlusion is the contact between the teeth of the upper and lower jaw. It is basically how your teeth fit together. The cusps (the high rounded parts on the tooth surface) of the tooth come in contact with the grove of the opposing arch teeth a maximum intercuspation is achieved which means the teeth fully bite.
Centric occlusion is the occlusion of opposing teeth when the mandible is in centric relation. Centric occlusion is the first tooth contact and may or may not coincide with maximum intercuspation. It is also referred to as a person's habitual bite, bite of convenience, or intercuspation position (ICP).