RECORDING OFJAW RELATION

Jaw Relation “ It is any relation between the mandible and the maxilla.”

It is a three dimensional relation ( vertical, anteroposterior and lateral).

DEFINTIONSCentric relation (It a bone to bone relation ) It is the most retruded unstrained

postion of the condyle in the glenoid fossae

Centric occlusionIt the relation of opposing occluding

surfaces when the mandible in centric relation to maxilla

The centric occlusion May or may not coincide with MI.

Occlusal Vertical Dimension• The distance measured between two points

when occluding members are in contact in centric occlusion.

Vertical Dimension of occlusion V D OThe vertical dimension of the face when

the teeth are in contact in centric occlusion.

Vertical Dimension of rest V D RThe vertical dimension of the face when

the mandible is in rest position.

V D R

V D O

Inter Occlusal Distance (Free Way Space) = 2 to 4 mm. ( F W S ) (0 to 10 mm.)

Vertical Dimension

V D R - F W S =

V D O

CENTRIC OCCLUDING RELATIONIT RECORDING A CENTRIC RELATION AT

ACCEPATABLE VERTICAL DIMENSION OF OCCLUSION

“ (Centric relation between maxilla and mandible at the proper vertical dimension of occlusion)

RECORDING JAW RELATIONSHIPS1. Check denture foundation.2. Establish facial contour.3. Establish occlusal plane.4. Maxillary face-bow record.5. Determination of vertical dimension of centric

occluding relation.6. Equalize pressure of occluding forces.7. Determine centric relation at the accepted

vertical dimension.8. Locking device ( recording the C.O.R. )

Check denture foundations.

Extension

Retention

Stability

Establish facial contour Facial contour depends on the

presence and alignment of teeth.

Teeth position or wax rim supports facial musculature and appearance.

Position of teeth governs tongue space and neutral zone.

Determination of occlusal plane

Aesthetic base. Phonetic base. Functional base. Mechanical base.

Anterior occlusal plane :Parallel to interpupillary line .

Posterior occlusal plane : Parallel to the ala tragus line .

Determination of Vertical Dimension of Centric Occluding Relation

Variables Affecting V D R :Short Term Variables :

1. Position of the patient's head .2. Respiration.3. Stress Situations .

Long Term Variables :1. Loss of the properioceptives impulses from the periodontal ligament.2. Age.

1- inharmonious facial proportions (Appearance).

2- Flexor muscles are in constant strain.

3- The lips are unnaturally separated and have a strained appearance.

4- The free-way space will be obliterated, inability

to find comfortable resting position.

5- Clicking of teeth may occur during speech and mastication.

Sequel Of Improper Registration Of V.D.0.A . High Vertical Dimension Of Occlusion :

Sequel Of Improper Registration Of V.D.0.

6- Generalized soreness of the residual ridge.

7. Difficulty in swallowing and gagging sensation (Discomfort).

8. Loss of biting power and muscular fatigue.

9. Interference with speech .

10. Pain under the basal seat and trauma to the supporting structures .

11. Accelerate bone resorption.

A . High Vertical Dimension Of Occlusion :

High Vertical Dimension

Flabby Tissue

High Vertical Dimension

High Plane of Occlusion

Obliteratedfree-way space

Establishing too little V.D.

1- Extensor muscles are strained.

2- Facial appearance is distorted.

3- Corners of the mouth may be

inflamed ( angular chielitis ).

4- Pain in tempro-mandibular joint.

5- Cheek biting.

6- Inefficiency: reduces biting force

Cheek Biting

MonoplaneHeavy BiteNo Horizontal Overlap

Angular Cheilitis

Corner of Mouth

Trouble in the T.M.J.The symptoms of the joint due to

reduced V.D. are manifested by Obscure pains and discomfort, Clicking sounds, Headaches and neuralgia running in

the ear. These symptoms may be resulted from

pressure on the tympanic nerve.

RECORDING JAW RELATIONSHIPS1. Check denture foundation.2. Establish facial contour.3. Establish occlusal plane.4. Maxillary face-bow record.5. Determination of vertical dimension of centric

occluding relation.6. Equalize pressure of occluding forces.7. Determine centric relation at the accepted

vertical dimension.8. Locking device ( recording the C.O.R. )

FACE-BOWSThe face-bow is a caliper-like device that is used to record the relationship of the jaws to the tempromandibular joint or ( opening axis of the jaws ) and to orient the casts in this same relationship to the opening axis of the articulator.

The face-bow transfer ensures that the casts are mounted centrally in correct relation to the inter-condylar axis

Types of Face BowsMandibular

“A device used to locate the transverse hinge or

the condylar axis.”

Maxillary

“A device used to record the relation between the maxilla and the TMJ and to transfer this relation

to the articulator.”

Mandibular Face Bow

Limited opening and closing allows the condylar rods to draw arcs. The rods are moved towards the center of the arcs, until they move in a point . The latter is called the still point and represents the condylar axis. The condyle in this position lies in the most retruded unstrained position in the glenoid fossa, so mandible and maxilla arein centric.

Maxillary Face Bow

Components:

GraduatedCondylar Rods

Tightening clamp

U Shaped Bow

Bite Fork

Universal Joint /Jack Clamp

Infraorbital Pointer

Graduations on the rod

Facia face bow

The ear-bow uses the external auditory

Maxillary Face Bow Record1- Bite fork is heated and inserted into the rim

.

Cont. Maxillary Face Bow Record

2-The condylar axis is then determined

11- 13 mm

Cont. Maxillary Face Bow Record

4- Universal joint once tightened , never opened.

Maxillary Face Bow Transfer

1- The slide bar clamp is unscrewd to remove assembly from the face.

Cont. Maxillary Face Bow Transfer

2- Assembly is now centralized on the articulator.

Equalize pressure of occluding forces

This means to produce even contact between the upper and lower occlusionblocks without displacement of denturesupporting tissues. This can only bedone on an easily displaceable materialsuch as softened wax.

Methods of recording the jaw relation

1- Terminal hinge axis method (Mandibular face bow method)

2- Chew-in or functional method

3- Graphic tracing method

4- Check bite / wax wafer/ wax registration method

1- Terminal hinge axis method

2- Chew in technique

3- Graphic tracing method

The resulting arrow represents the centric and eccentric relations

TYPES OF TRACERSA- Intraoral tracer

B- Extraoral tracer

4- Check bite technique(Wax wafer method)

Methods to guide the mandiblein centric relation

1- Tongue retrusion .2- Swallowing .3- Biting operator’s fingers .4- Relaxation .5- Fatigue .6- Head position .7- The temporalis muscle check .

Wax registration method

or Check bites

or Wax wafer method

Excursive methods

orGraphic tracing

method

Eccentric jaw relationships

Protrusive recordRight lateral recordLeft lateral record

Locking deviceV shaped notches can be carved onthe upper occlusion rim and the finalclosure is done on softened wax. Theimprints of these notches are used tolock upper and lower occlusion blocks.