1. The document discusses key concepts related to occlusion and articulation including centric relation, centric occlusion, and maximal intercuspal position. 2. It provides guidelines for making wax rims and records for edentulous patients including determining the occlusal vertical dimension and freeway space. 3. The process of making a centric relation record is described which involves using bimanual manipulation to guide the mandible into the centric position while soft tissue is registered.

1. Centric Records
Dr. Muaiyed. Mahmoud. Buzayan, BDS
MClinDent Malaysia
AF AAMP USA

2. Occlusion
 the static relationship between the incising or
masticating surfaces of the maxillary or mandibular teeth
or tooth analogues
 Deals with the static relationship of the opposing teeth.
Articulation
Deals with the dynamic relationship of the opposing teeth.
Protrusive and lateral movements

3.  Centric Relation
The maxillomandibular relationship in which the condyles
articulate with the thinnest avascular portion (non innervated) of
their respective disks with the complex in the anterior-superior
position against the shapes of the articular eminencies. This position
is independent of tooth contact. It is restricted to a purely rotary
movement about the transverse horizontal axis

4.  Centric Occlusion
The occlusion of opposing teeth when the mandible is in
centric relation. This may or may not coincide with the maximal
intercuspal position.
 Maximal intercuspal position
The complete intercuspation of the opposing teeth
independent of condylar position, sometimes referred to as the
best fit of the teeth regardless of the condylar position

8. 1. Hapitual class III (ridge to ridge)
2. Edentulous patients have more
difficulty determining where their
denture teeth should contact (No
periodontal membrane)
3. Record base fit (loose) and wax rim
(dimensions) changes confuse some
patients

9. Occlusal position to be acceptable, it should be:
1. Conducive to health
 Harmless to TMJ
 Painless
2. Relatively repeatable
 position can be checked and repeated, before dentures
completed
 CR is not far from CO at same occlusal vertical dimension

10. Terminal Hinge axis
An imaginary line around which the mandible may rotate within the
sagittal plane
 Hinge Position is Repeatable (axis of circle)
 relatively centered
 patient can find stable occlusal contacts relatively easily
 allows change in vertical dimension
 Can be transferred to the articulator

12. 1. When entire occlusion being
restored (full mouth rehabilitation)
 No remaining posterior centric stops
2. When complete, or removable
partial dentures involve the entire
occlusion
3. Restoring/ Increasing of vertical
dimension (OVD)
 Tooth surface loss (TSL) erosion,
attrition and abrasion

13. 1. Stable occlusion
2. Posterior centric stops present
3. No reason to change current
occlusion
 Use maximal intercuspation

14. Occlusal Vertical Dimension

15. Plane of occlusion
An imaginary surface which is related anatomically to the incisors and
tips of the occluding surfaces of the posterior teeth. In complete
denture prosthodontics, this plane is parallel to Camper's line.
Camper's plane
A plane established by the inferior border of the right or left ala of the
nose and the superior border of the tragus of both ears.

16. Physiologic rest position
The habitual postural position of the mandible when the patient is
resting in an upright position and the condyles are in a neutral,
unstrained position in the glenoid fossae.
Vertical relation at rest position VDR
The length of the face when the mandible is in the physiologic rest
position. The wax rims should not touch.
Vertical dimension of occlusion VDO
The distance measured between two points when the occluding
members (upper and lower Occlusion rims) are in contact. It is
about 2-4mm less than Vertical Relation at Rest Position.
Freeway Space (interoclusal distance)
the difference between the vertical dimension of rest and the
vertical dimension while in occlusion. (2- 4 mm)
Freeway space= VDR- VDO
Centric relation record
A registration of the relationship of the maxilla and the mandible
in centric relation made at the established vertical relation of
occlusion.

18. ????

19. Amount of separation between mandible & maxilla when
denture teeth are in contact
Over closure
VDO
Restoring with prosthesis

20.  Used to relate casts on an articulator
 Record bases simulate the finished denture base
 Wax occlusion rims simulate the position of the
teeth
 Occlusion rims slightly bulkier, provide additional
stability during record making

21.  Required for record making and phonetic tests
 Centric relation record will be inaccurate if loose
 Use denture adhesive if slightly loose
 Much looseness – REMAKE
 Causes of Poor Retention
1. Poor adaptation of resin to cast
2. Over- or under-extension
3. Excessive block-out of the cast before making the denture base
 Starting Point for VDO;
adjust the height of the occlusal blocks separately using average
dimensions:
Maxillary - 23 mm
Mandibular - 18 mm

22.  Maxillary rim slightly facial to compensate for
ridge resorption.
 (Incisal display) Anterior height 1-2 mm below the
lip at rest/when the patient slightly smiles
10-20mm 3-4mm
20-25mm 2mm
26-30mm 1mm
Lip Length Incisal Display

23. Horizental extension;
 Touches wet line of lower lip (the vermilion border) when
‘F’ or ‘V’ sounds (Count ‘50-60’).
 The labial surface of the wax anterior to incisive papilla 8
– 10 mm
 Lips should be unstrained
 To confirm correct wax block dimensions:
1. Naso-labial angle ≈ 90°
2. Philtrum depressed (not full)
3. Vermilion border showing (not invereted)

24.  Frontal (Mediolaterally) the occlusal plane parallels the pupils (Fox plane can
be used
 Anterio-posteriorly, The Maxillary denture occlusal plane should be parallel
to the camper’s line

25. Extension:
 Posteriorly, the occlusion rim intersects 1/2 - 2/3
up the retromolar pad.
 Anterior height even with the corners of the
mouth when the lip is relaxed (Buccal corridor
 1-2 mm horizontal overjet
 Unstrained lips, Vermilion border showing

26. Amount of separation between mandible & maxilla
when denture teeth or wax rims are in contact
Over closure
VDO
Restoring with prosthesis

27.  The target is to get unstrained Physiologic Rest Position
(PRP) within the average
1. At rest, lips barely touching
2. Occlusion rims should not touch
3. With INTEROCLUSAL DISTANCE (ID) FWS between wax rims at
physiologic rest position ( 2-4 mm)
 PRP (OVR) = ID (2- 4mm) + OVD

28. 1. Measure difference between PRP & OVD to get the
average ID
2. Feel to ensure smooth movement of mandible
3. Phonetics tests ‘Closest Speaking Space
4. Face profile (not long/ short face)
 Check with all the previous techniques to ensure
acceptable OVD. No one technique 100% correct.

29. 1. place the maxillary record base in the patient's mouth.
2. Seat the patient in a comfortable upright position unsupported
by a head rest. Soft tissue position affected by posture. Mark a
small dot on on the nose and the chin to serve as reference
points. Ask the patient to swallow and relax the jaw several
times.
3. Use external points for ease of measurement Small dots under
columnella (or on the nose tip) & mid-symphisis Use Boley
Gauge or ruler
4. Measure the distance between dots At PRP and OVD, the
difference is ID
5. the operator should adjust the wax rims until the ID is (2 – 4
mm)

30.  Open and close until lips barely touch - Physiologic Rest
Position (PRP). Measure distance between dots
 Open and close until rims touch without interference and
uniformly.
 Measure distance between dots (OVD)
 These measurement will be different each appointment.
However , the ID would be in the same range.

31. Closest Speaking Space
 Sibilant sounds ("s", "z", sh", ch")
(‫س‬,‫ش‬)‫مسمار‬‫سلوم‬
 Rims should be at least 1 mm apart
 No need to get clear sounds and
pronunciation yet.

32. If there was no ID or ID less than 2mm Excessive OVD
Wax Rims Too High.
If there was insufficient interocclusal distance
 Remove wax from one or both of the rims
◦ Use large wax formers
◦ wax spatulas
◦ Bunsen burner and torch

33.  Flat and even contact along entire occlusal surface
 If uneven contact, patient may be forced into eccentric
position
 Scribe lines parallel to the opposing
occlusal rim. Use as a guides during
reduction

34.  Making three marks on the wax rims, when the patient in
Centric Position
 Scribe three widely separated lines between maxillary &
mandibular rims
 Remove, superimpose the lines
 Eliminate contacts between record bases, record
base/occlusion rims

36. Excessive Occlusal Vertical Dimension Inadequate Occlusal Vertical
Dimension
Sore muscles Collapsed Appearance
Soft tissue sore spots chin too close to the nose or
protruding jaw
Rapid bone resorption Fatigue when chewing
Dentures click during speech Sore muscles or joints
Long face Short face

38. 1. Bimanual manipulation
2. Chin point guidance

39. Generally
1. Patient sit in a slightly supine position
2. Occlusion rim notched to aid stabilizing the record
bases
3. Index fingers on the rim, thumbs under symphysis
(Chin point guidance)
4. Jiggle the mandible
5. Mandible should freely arc
6. Allow the patient to close into contact
7. Do NOT push the mandible or dislodge the record base
8. Medium (record material) must be soft
9. Minimal closing pressure

40. 1. Place 3 widely separated lines between
the rims in the centric position
2. CRITICAL! Check that record base
heels/rims do not touch
3. Two sharp “V”-shaped notches in the
molar/premolar area of each sided wax,
depth 1-2 mm

41. 1. Place occlusion rims intraorally
2. PVS registration material, over entire
occlusal rim
3. Have patient close into record
4. Ensure smooth arc of closure, no
horizontal deviations
5. Use index fingers to stabilize lower record
base
6. Want flat record, no excess on sides of
rims
7. Excess material recording of the sides of
the rim can cause deflection when checking
record

44.  Ensure record is repeatable
 Increase the height of incisal pin
1 mm, invert articulator
 Place wax rims together, lute with
sticky wax - 4 spots