Horizontal Jaw relation

• 1. GOOD AFTERNOONPresented by:- Rutvik A. Patel (IV BDS)1

2. HORIZONTAL JAW RELATION CONTENTS: Introduction Types Centric relation Significance Salient feature Retruding the mandible Factors influencing centric relation Method of recording centric relation2 3. INRODUCTION Jaw relation is defined as any relation of the mandible to maxilla It is recorded to measure the extensibility & movements permissible by the patients TMJ TYPESOrientationVerticalHorizontal 3 4. HORIZONTAL RELATIONMaxillomandibular relation in which the condyles articulate with the thinnest avascular portion of their respective discs with the complex in the antero-superior direction against the slope of articular eminence. 4 5. Horizontal jaw relation Relationship of mandible to maxilla in a horizontal plane Two types: 1. Centric jaw relation 2. Eccentric jaw relationHorizontal jaw relation 5 6. CENTRIC JAW RELATION What is centric relation ? A maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective disks with the complex in the anterior superior position against the slopes of the articular eminences. This position is independent of tooth contact. This position is clinically discernible when the mandible is directed superiorly and anteriorly and restricted to a purely rotary movement 6 about a transverse horizontal axis. 7. SIGNIFICANC E Proprioceptive impulses guide the mandibular movement The centric relation position acts as a proprioceptive centre to guide the mandibular movements.7 8. SALIENT FEATURES OF CENTRIC RELATION 1. Learnable, Repeatable, Recordable. 2. Act as a centre 3. Functional movements are performed in this position 4. Most unstrained position 5. Arrangement of muscle acting on TMJ 6. The cast should be mounted in centric relation It is a learned position and the dentist should teach the patient 8 9. RETRUDING THE MANDIBLE A. Verbal instruction to the patient B. Get the feeling of pushing your upper jaw out and close back teeth together C. Retrusion of the tongue D. Rapid tapping of the occlusal rim E. Tilting head backwards F. Ask patient to swallow CDE9 10. Difficulties in retruding mandible 1. BIOLOGICAL CAUSE Lack of muscle co-ordination Habitual eccentric jaw relation 2. PSYCHOLOGIC PROBLEM Lack of proper instruction by dentist Inability to follow dentist3. MECHANICAL PROBLEM Poorly fitting base plates10 11. FACTORS INFLUENCING CENTRIC RELATION 1. The resiliency of the supporting tissues 2. The stability of the recording bases 3. The TMJ and its neuromuscular mechanisms 4. The character of the pressure applied 5. The technique & devices used 6. The skill of the dentist 7. The health and cooperation of the patient 8. The maxillomandibular relationship 9. The posture of the patient 10. The character or size of the residual alveolar arch11. The amount and character of the saliva 12. The size and position of the tongue 11 12. METHOD OF RECORDING CENTRIC RELATION Physiologic method Pressureless or static method Pressure method Functional method Needle-House method Patterson method Graphic method Intraoral method Extraoral method Radiographic method 12 13. Physiologic method Troug hA Pressureless or static method 1. Nick & Notch method most commonly used method PROCEDURE A.B NotchB. C. D. E.CRemove 3 mm of wax either side on mandibular occlusal rim till the distal end. This depression is called as trough. Nick & Notch made on the corresponding area on maxillary occlusal rim. Aluwax is placed in trough & soften it and place in patients mouth. Ask patient to bite on occlusal rims Remove it and cut the excessD4.5 mm13 14. 2. Stapler pin method After recording centric relation occlusal rims are indexed using a bunch of stapler pins. This method is not preferred because centric relation record cannot be verified14 15. Pressure method In this method we will fabricate lower occlusal rim excess in height Entire lower occlusal rim is softened & inserted in mouth Guide patient to close mouth in centric relation till the predetermined vertical dimension Remove occlusal rims, cool it and articulate15 16. Functional Needle-House method method - uses occlusal rims made from impression compound with four metal styli placed in the maxillary rim.MP MRL- when the mandible moves with the styli contacting the rim, the styli cut four diamond shaped tracings.ML L CR- the tracings incorporate the movements in three planes, and the records are placed on a suitable articulator to duplicate the record.16MP-Maximum protrusive, MLLMaximum left lateral, MRLMaximum right lateral, CRCentric relation 17. Patterson Method - Uses wax occlusal rims. - A trench is made in the mandibular rim, and a mixture of half plaster and half carborudum paste is placed in the trench. - When the plaster and carborundum are reduced to the pre-determined vertical dimension, patients are instructed to retrude the mandible and occlusion rims joined. 17 18. Graphic method Use graphs or tracings to record the centric jaw relation Most accurate methodTypes: 1. Arrow point tracing - Single plane 2. Pantograph - Three dimensional18 19. Arrow point tracing Tracing made using Gothic arch tracer Concept Pen like pointer Recording plate Central bearing deviceCentral bearing plateCentral bearing point Central arrow point tracing The pattern obtained on the horizontal plate used with central bearing tracing device 19 20. Types of Arrow point tracer1. Intraoral Central bearing device is located intra orally Procedure Insert central bearing device into mouth Adjust central bearing point on central bearing plate Now patient is asked to do movement, then tracing is removed and examined It should resemble arrow point with sharp apex 20 21. 2. Extraoral Have attachment that projects outside the mouth Occlusal rim Procedure Central bearing device is attached with the occlusal rims Place occlusal rims in the mouth and patient is asked to do movements Tracing is examined for sharp apexOcclusal rim21 22. Pantographic tracing Most accurate method available Pantographic tracer: An instrument used to graphically record one or more planes path of mandibular movement and to provide information for the programming of the articulator. It has 6 flags: - 4 near condyle - 2 in anterior region22 23. CONCLUSIO N Fabrication of complete denture involves various steps out of which recording jaw relation is one of the most important step. There are various technique used to record jaw relation. By recording proper jaw relation functional efficiency & longevity of the prosthesis is increased.23 24. REFEREN CE Textbook of PROSTHODONTICS Deepak Nallaswamy {First edition-2009 (Deepak Nallaswamy Veeraiyan, Karthikeyan Ramalingam, Vinaya Bhat )} Prosthodontic Treatment for Edentulous Patient Boucher{12th Edition George A. Zarb, Charles L. Bolender, Steven E. Eckert, Rhonda F. Jacob, Aaron H. Fenton, Regina Mericske-Stern)} Google search 24