Centric relation
Encyclopedia
In dentistry, centric relation is the mandibular jaw position in which the head of the condyle is situated as far anterior and superior
Commonly used terms of relationship and comparison in dentistry
There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...

 as it possibly can within the mandibular fossa/glenoid fossa.

This position is used when restoring edentulous patients with removable
Dentures
Dentures are prosthetic devices constructed to replace missing teeth, and which are supported by surrounding soft and hard tissues of the oral cavity. Conventional dentures are removable, however there are many different denture designs, some which rely on bonding or clasping onto teeth or dental...

 or either implant
Dental implant
A dental implant is a "root" device, usually made of titanium, used in dentistry to support restorations that resemble a tooth or group of teeth to replace missing teeth....

-supported hybrid or fixed
Fixed prosthodontics
Fixed prosthodontics in dentistry is a technique used to restore teeth, using fixed restorations , which include crowns, bridges, inlays, onlays, and veneers. Prosthodontists are specialist dentists who have undertaken training recognized by academic institutions in this field...

 prostheses. Because the dentist want to be able to reproducibly relate the patient's maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...

 and mandible, but the patient does not have teeth with which to establish his or her own vertical dimension of occlusion
Vertical dimension of occlusion
Vertical dimension of occlusion, or VDO, also known as occlusal vertical dimension is a term used in dentistry to indicate the superior-inferior relationship of the maxilla and the mandible when the teeth are situated in maximum intercuspation....

, another method has been devised to achieve this goal. The condyle can only be in the same place as it was the last time it was positioned by the dentist if it is consistently moved to the most superior and anterior position within the fossa.

Centric relation is an old concept in dentistry based on an old mechanical viewpoint of dentistry. There are over 26 different definitions of Centric Relation since the term was first developed as a starting point for making dentures. It is not a physiologic position but rather a border position that is used for reproducibility. The Temporomandibular Joint, does not normally function in a Centric Relation position. Long centric is a term that describes a functional position that patients restored in Centric Relation frequently migrate to. Centric Relation is a border position that is inherently unstable. Mandibular fossa is put anterior and superior as possible. (First aid for the NERB I)

Centric Relation believers state that the relationship of the mandible to the maxilla when the properly aligned condyle-disc assemblies are in the most superior position against the eminentiae irrespective of Occlusal Vertical Dimension (OVD) or tooth position.

At the most superior position, the condyle-disc assemblies are braced medially, thus centric relation is also the midmost position.
A properly aligned condyle-disc assembly in centric relation can resist maximum loading by the elevator muscles with no sign of discomfort.
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