According to the glossary of prosthodontics,

‘a maxillary-mandibular relationship, independent of tooth contact, in which the condyles articulate in the anterior-superior position against the posterior slopes of the articular eminences’

JPD, The Glossary of Prosthodontic Terms

Centric relation is not to be confused with centric occlusion, which is a term no longer used. In centric relation, the mandible is restricted to a rotary movement. The mandible is in an un-strained, physiologic, maxilomandibular relationship. In this position, the patient can make vertical, lateral, or protrusive movements.

What are the two most important criteria for achieving centric relation (CR)?

1. Completely released inferior lateral pterygoid muscle on both sides of the head
2. The proper alignment of the articulating disk with the condyle

True or False: The mandible can be in CR even when the teeth are separated or even if there are no teeth in the jaw?

True. This can be useful for patients that are edentulous. CR is a clinically repeatable position when properly utilized.

Ferro, K., Morgano, S., Driscoli, C., Freilich, M., Guckes, A., Knoernschild, K., & McGarry, T. (2017). The Glossary of Prosthodontic Terms. The Journal of Prosthetic Dentistry, 117(5). doi: 10.1016/j.prosdent.2016.12.001

Dawson, P. E. (2007). Functional occlusion: from Tmj to smile design. St. Louis, MO: Mosby.