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JAW RELATION.  “ It is any relation between the mandible and the maxilla.”  It is a three dimensional relation ( vertical, anteroposterior and lateral).

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Presentation on theme: "JAW RELATION.  “ It is any relation between the mandible and the maxilla.”  It is a three dimensional relation ( vertical, anteroposterior and lateral)."— Presentation transcript:

1 JAW RELATION

2  “ It is any relation between the mandible and the maxilla.”  It is a three dimensional relation ( vertical, anteroposterior and lateral).

3 Centric relation (It a bone to bone relation )  It is the most retruded unstrained postion of the condyle in the glenoid fossae

4  Centric occlusion It the relation of opposing occluding surfaces when the mandible in centric relation to maxilla The centric occlusion May or may not coincide with MI.

5 Occlusal Vertical Dimension The distance measured between two points when occluding members are in contact in centric occlusion.

6 Vertical Dimension of occlusion V D O The vertical dimension of the face when the teeth are in contact in centric occlusion.

7 Vertical Dimension of rest V D R The vertical dimension of the face when the mandible is in rest position.

8 V D R V D O

9 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

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11  CENTRIC OCCLUDING RELATION IT RECORDING A CENTRIC RELATION AT ACCEPATABLE VERTICAL DIMENSION OF OCCLUSION “ (Centric relation between maxilla and mandible at the proper vertical dimension of occlusion)

12 1. 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. )

13  Extension  Retention  Stability

14  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.

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17  Aesthetic base.  Phonetic base.  Functional base.  Mechanical base.

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22 Anterior occlusal plane : Parallel to interpupillary line.

23 Posterior occlusal plane : Parallel to the ala tragus line.

24 Determination of Vertical Dimension of Centric Occluding Relation

25 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.

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27 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 :

28 Sequel Of Improper Registration Of V.D 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 :

29 High Vertical Dimension Flabby Tissue

30 High Vertical Dimension High Plane of Occlusion Obliterated free-way space

31 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

32 Cheek Biting Monoplane Heavy Bite No Horizontal Overlap

33 Angular Cheilitis Corner of Mouth

34 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.

35 1. 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. )

36 The 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

37 Mandibular “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.”

38 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 are in centric.

39 Components: Graduated Condylar Rods Tightening clamp U Shaped Bow Bite Fork Universal Joint / Jack Clamp Infraorbital Pointer Graduations on the rod

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43 1- Bite fork is heated and inserted into the rim.

44 2-The condylar axis is then determined mm

45 4- Universal joint once tightened, never opened.

46 1- The slide bar clamp is unscrewd to remove assembly from the face.

47 2- Assembly is now centralized on the articulator.

48 This means to produce even contact between the upper and lower occlusion blocks without displacement of denture supporting tissues. This can only be done on an easily displaceable material such as softened wax.

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50 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

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53 3- Graphic tracing method

54 The resulting arrow represents the centric and eccentric relations

55 A- Intraoral tracer B- Extraoral tracer

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57 1- Tongue retrusion. 2- Swallowing. 3- Biting operator’s fingers. 4- Relaxation. 5- Fatigue. 6- Head position. 7- The temporalis muscle check.

58 Wax registration method or Check bites or Wax wafer method

59 Excursive methods or Graphic tracing method

60 Protrusive record Right lateral record Left lateral record

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62 V shaped notches can be carved on the upper occlusion rim and the final closure is done on softened wax. The imprints of these notches are used to lock upper and lower occlusion blocks.

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