# Centric Relation Basics > Centric relation in BDS Prosthodontics: condyle-disc-eminence definition, gothic arch recording, bilateral manipulation and why it guides tooth setting. - Canonical URL: https://prepelephant.com/topics/bds/prosthodontics/centric-relation-basics - Exam / course: BDS · Subject: Prosthodontics - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Centric Relation Basics", PrepElephant, https://prepelephant.com/topics/bds/prosthodontics/centric-relation-basics ## Direct answer Centric relation is a bone-to-bone relationship; centric occlusion is a tooth-to-tooth one — and in the edentulous patient only the first survives to be recorded. By the current Glossary of Prosthodontic Terms definition, centric relation is the maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their discs, seated anterosuperiorly against the posterior slopes of the articular eminences, independent of tooth position or contact. Around this position the mandible can pure-rotate on a terminal hinge axis for the first 20–25 mm of opening, which is what makes it reproducible: a jaw record made in centric relation can be repeated and transferred to an articulator, giving the only stable reference an edentulous mouth offers for building occlusion. ## What you must remember - **Definition anchors:** condyle–thin avascular central disc–posterior slope of eminence; bilaterally symmetric; independent of teeth — examiners expect the current wording, not the older "most retruded" version. - **Why edentulous records use it:** tooth-guided positions vanished with the teeth; centric relation depends only on ligaments and muscles, so it is the repeatable starting point for jaw relation records. - **Terminal hinge axis:** pure rotation possible to roughly 20–25 mm interincisal opening; the axis the facebow approximates and the articulator reproduces. - **Recording methods in three families:** static interocclusal records (zinc oxide eugenol, waxes, plaster, silicone between rims); functional chew-in records; and graphic methods — the gothic arch (needle-point) tracing, whose apex marks centric relation. - **Guiding techniques:** bilateral manipulation with chin-point support (gentle arc closure, never pushing the jaw backwards — pushing recruits protrusion), leaf gauge, and the tongue-to-posterior-palate-and-swallow trick for edentulous patients. - **Recording media:** zinc oxide eugenol paste on rims or medium-body silicone are routine; the material must offer resistance so the rims register the position, not the mandible's drift. - **Centric relation versus retruded contact position:** RCP is a tooth-defined first rearward contact; centric relation is the joint position in which that contact is arranged to occur. ## Recording it with a gothic arch, walked through Wax rims are adjusted to the agreed vertical dimension, and a central bearing screw is fixed to the maxillary rim with a tracing table on the mandibular rim (extraoral tracing apparatus outside the lips, or intraoral plates within). With the patient guided into gentle hinge movement, an arrow-shaped trace is scribed: the apex posteriorly marks centric relation, the limbs the right and left lateral excursions, and a flicker of protrusion the anterior chase. A acrylic or wax index is keyed into a perforation or the tracer is locked at the apex, the recording paste is syringed between the rims, and the mandible is allowed to arc closed into the apex without translation. The mounted casts now carry the condylar axis relationship faithfully. The same logic, less gadgetry, applies with bilateral manipulation: the operator stabilises the chin, guides small hinge movements until the muscles relax, and lets the jaw close on the arc into the record medium. ## Where students slip The classic viva trap is definitional drift — describing centric relation as "the most retruded position of the mandible" earns correction, because modern teaching seats the condyles up the eminence slopes rather than dragging them back down the fossa walls. The second error is force: pushing the chin backwards recruits the patient's protrusive reflex and records a protruded or deflected position; manipulation guides, it never shoves. The third is reading the gothic arch — the apex is centric relation, not the centre of the plate, and a tracing without a sharp apex means the patient was translating, so it must be repeated, not interpreted. ## Frequently asked questions ### Define centric relation in current usage. The maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their discs against the posterior slopes of the articular eminences, independent of tooth contact. ### Why are edentulous jaw records made in centric relation? It is the only reproducible, tooth-independent reference remaining once natural occlusion is lost, allowing repeatable articulator mounting and a stable occlusal scheme. ### What does the apex of a gothic arch tracing represent? The terminal hinge position of pure rotation — centric relation; the splayed limbs represent lateral excursions and should be symmetrical. ### Name three families of centric relation recording methods. Static interocclusal records (ZOE, waxes, silicone), functional chew-in records, and graphic tracings such as the needle-point gothic arch. ### Why must the mandible never be pushed backwards during recording? Forceful retrusion activates protective protrusive muscles and records a deflected position; gentle bilateral guidance along the arc of closure lets centric relation occur naturally.