What is jaw relation in dentistry?
What is jaw relation in dentistry?
Jaw relation (or the maxillomandibular relationship) refers to the position of the mandible (lower jaw) relative to the two maxillae (upper jaw) and can be described as a tooth-to-tooth relationship between maxillary and mandibular teeth or as a bone-to-bone relationship between the maxillae and mandible.
Why do we record jaw relation?
To establish the correct orientation and level of the occlusal plane. To produce the correct shape for the labial, buccal and palatal surfaces.
What is vertical jaw relation?
The distance between two selected points one on the fixed part (maxillae) and one on the movable part (mandible) when occluding members ( bite rim or teeth) are in contact. – VDR: – Vertical dimension of Rest.
Why is centric relation important?
The reason centric relation is so important is because it is the highest possible position of the condyle- disc assemblies that is achieved by coordinated muscle activity when the jaw is closed. At this uppermost position, the jaw joints are seated firmly against a bony stop so they cannot go higher.
What are the classes of jaw relationship?
Class 1: Class I is a normal relationship between the upper teeth, lower teeth and jaws or balanced bite. Class II: Class II is where the lower first molar is posterior (or more towards the back of the mouth) than the upper first molar.
What is VDO and VDR?
The vertical dimension of occlusion can roughly be measured by asking the patient to say “Emma.” The position of the lower jaw on the “a” sound is called the vertical dimension at rest (VDR), which is roughly 3mm greater than a patient’s VDO.
How is VDO measured?
A measurement method that can be used to determine VDO is to measure from the cementoenamel junction (CEJ) or gingival margins of the maxillary central incisors to the CEJ or gingival margins of the mandibular central incisors.
What is the difference between centric relation and centric occlusion?
Centric occlusion refers to a position of maximal, bilateral, balanced contact between the cusps of the maxillary and mandibular arches. Centric relation is the most retruded, unstrained position of the mandibular condyle within the temporomandibular joint (TMJ), that is, within the glenoid fossa.
