Vertical Jaw Relations: Concept, Principle, Methods for recording (VDR, VDO, Freeway space)

Recording accurate jaw relations is of paramount importance when preparing a prosthesis. Vertical dimension is based on the principle that the repetitive contracted length of the elevator muscles determines the VD at occlusion. The VDO refers to the vertical position of the mandible in relation to the maxilla when the upper and lower teeth are intercuspated at the most closed position. Maximal intercuspation of the posterior teeth determines the existing VDO. If the VDO must be changes, it should be determines at the point of anterior teeth contact. VDR or physiologic rest position of the mandible is the position when the elevator and depressor muscles are in a state of equilibrium or balance. this position most commonly results in a separation of the maxillary and mandibular teeth of about 3mm at the first premolar region. This separation is called the "interocclusal space".