# Complete Denture Jaw Relations > Jaw relations for NEET-MDS Prosthodontics: vertical dimension methods, freeway space, centric relation recording and protrusive records. - Canonical URL: https://prepelephant.com/topics/neet-mds/prosthodontics/complete-denture-jaw-relations-mds - Exam / course: NEET-MDS · 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: "Complete Denture Jaw Relations", PrepElephant, https://prepelephant.com/topics/neet-mds/prosthodontics/complete-denture-jaw-relations-mds ## Direct answer Jaw relation records transfer the patient's mandibular position to the articulator in two dimensions: vertical relation (how far apart the jaws should be at occlusion) and horizontal relation (where the mandible closes relative to the maxilla). The vertical relation is fixed by establishing occlusal vertical dimension on occlusion rims — most often physiologic rest position minus the 2-4 mm of freeway space, cross-checked with phonetics and facial harmony. The horizontal relation is recorded in centric relation, a reproducible border position, at the agreed vertical dimension, using wax check records or a Gothic arch tracing; a protrusive record then programs the condylar guidance of a semi-adjustable articulator so teeth can be arranged in balanced occlusion. ## What you must remember - **Order of the appointment:** occlusion rims contoured (lip support, occlusal plane with a Fox plane) → vertical relation → horizontal (centric) relation → protrusive record → facebow transfer and mounting. - **Freeway space is 2-4 mm** — the gap between occlusion and physiologic rest position; it is found, never set, by observing the relaxed mandible after swallowing. - **Vertical dimension methods:** physiologic rest position, facial thirds and measurements, phonetics (closest speaking space about 1-2 mm on "S" sounds, Silverman), swallowing, facial expression, and TENS (Jankelson myo-monitor) or cephalometric approaches. - **Excessive vertical dimension** gives a strained expression, tight lips, clicking, masticatory muscle pain, gagging, and the "Friday denture" the patient cannot wear all day; **reduced dimension** gives a sunken lower third, angular cheilitis, drooping commissures and noisy contacts. - **Centric relation record** is taken at the established vertical dimension with a static quick-setting material (soft wax, ZOE paste, fast silicone) and verified by a repeat record. - **Protrusive record** (about 5-6 mm of protrusion) programs horizontal condylar guidance; Hanau's formula L = H/8 + 12 derives the lateral condylar guidance. - **Occlusal plane:** parallel to the interpupillary line anteriorly and Camper's line (ala to tragus) posteriorly. ## A typical jaw relation appointment Rims are first made credible: the maxillary rim supports the lip so the philtrum and vermilion border look natural, the incisal edge shows 1-2 mm below the high lip line at rest, and the occlusal plane is checked with a Fox plane against the pupils and Camper's line. The mandibular rim is then adjusted to meet the maxillary rim evenly at a vertical dimension estimated from rest position: mark a point on the nose and chin, measure the rest distance, and reduce the rim height until occlusion leaves 2-4 mm less than that measurement. Phonetics double-checks it — with "S" sounds (sixty-six, Mississippi) the rims should nearly touch with about 1-2 mm of closest speaking space. For centric relation, seat the patient upright and rely on gentle guidance rather than command: the operator supports the chin, asks the patient to relax, and helps the mandible hinge closed into the retruded arc; two notches or a line of softened wax indexing the rims confirms the record. A protrusive wax record follows, and the casts are mounted with a facebow so the articulator opens like the patient. ## How the exam frames it The examiner's favourite contrast is freeway space versus closest speaking space: the 2-4 mm rest space is measured without any task, while the 1-2 mm closest speaking space is measured during "S" phonation — mixing them up flips the answer options. The second staple asks which record is taken at the vertical dimension: centric relation is recorded at the established occlusal vertical dimension, never at rest position. Finally, image-based questions show a Gothic arch tracing and ask what the apex represents — centric relation — testing whether the candidate has actually linked this appointment to the tracing method. ## Frequently asked questions ### What is freeway space and how much is it normally? The space between the occlusal surfaces at physiologic rest position and at occlusion, averaging 2-4 mm; it is the safety margin used to set occlusal vertical dimension. ### Which phonetic test verifies vertical dimension? Closest speaking space: when the patient counts "sixty-six" or says "Mississippi", the teeth or rims should come within about 1-2 mm of contact without clashing. ### In which order are vertical and horizontal relations recorded? Vertical relation is established first on the rims, because centric relation must be recorded at the established occlusal vertical dimension; recording them in reverse creates a double error. ### What is the purpose of the protrusive record? It programs the horizontal condylar inclination of a semi-adjustable articulator so eccentric movements can be simulated and balanced occlusion arranged. ### What causes a "Friday denture"? An excessive vertical dimension — the patient manages the new prosthesis for part of the day but the fatigued muscles and strained tissues force its removal by evening.