11CENTRIC 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)
12RECORDING JAW RELATIONSHIPS Check denture foundation.Establish facial contour.Establish occlusal plane.Maxillary face-bow record.Determination of vertical dimension of centric occluding relation.Equalize pressure of occluding forces.Determine centric relation at the accepted vertical dimension.Locking device ( recording the C.O.R. )
14Establish 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.
22Anterior occlusal plane : Parallel to interpupillary line .
23Posterior occlusal plane : Parallel to the ala tragus line .
24Determination of Vertical Dimension of Centric Occluding Relation
25Variables Affecting V D R : Short Term Variables :Position of the patient's head .Respiration.Stress Situations .Long Term Variables :Loss of the properioceptives impulses from theperiodontal ligament.2. Age.
27Sequel Of Improper Registration Of V.D.0. A . High Vertical Dimension Of Occlusion :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, inabilityto find comfortable resting position.5- Clicking of teeth may occur during speech and mastication.
28Sequel Of Improper Registration Of V.D.0. A . High Vertical Dimension Of Occlusion :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.
30High Vertical Dimension Obliteratedfree-way spaceHigh Plane of Occlusion
31Establishing too little V.D. 1- Extensor muscles are strained.2- Facial appearance is distorted.3- Corners of the mouth may beinflamed ( angular chielitis ).4- Pain in tempro-mandibular joint.5- Cheek biting.6- Inefficiency: reduces biting force
34Trouble in the T.M.J.The symptoms of the joint due to reduced V.D. are manifested byObscure pains and discomfort,Clicking sounds,Headaches and neuralgia running in the ear.These symptoms may be resulted from pressure on the tympanic nerve.
35RECORDING JAW RELATIONSHIPS Check denture foundation.Establish facial contour.Establish occlusal plane.Maxillary face-bow record.Determination of vertical dimension of centric occluding relation.Equalize pressure of occluding forces.Determine centric relation at the accepted vertical dimension.Locking device ( recording the C.O.R. )
36FACE-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
37“A device used to locate the transverse hinge or the 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.”
38Mandibular Face BowLimited opening and closing allows the condylar rods to draw arcs.The rods are moved towards the center of the arcs, until they movein a point . The latter is called the still point and represents thecondylar axis. The condyle in this position lies in the most retrudedunstrained position in the glenoid fossa, so mandible and maxilla arein centric.
39Maxillary Face Bow Components: Graduations on the rod Graduated Condylar RodsInfraorbital PointerBite ForkTightening clampUniversal Joint /Jack ClampU Shaped Bow
43Maxillary Face Bow Record 1- Bite fork is heated and inserted into the rim .
44Cont. Maxillary Face Bow Record mm2-The condylar axis is then determined
45Cont. Maxillary Face Bow Record 4- Universal joint once tightened , never opened.
46Maxillary Face Bow Transfer 1- The slide bar clamp is unscrewd to remove assemblyfrom the face.
47Cont. Maxillary Face Bow Transfer 2- Assembly is now centralized on the articulator.
48Equalize pressure of occluding forces This means to produce even contactbetween the upper and lower occlusionblocks without displacement of denturesupporting tissues. This can only bedone on an easily displaceable materialsuch as softened wax.