Jaw Relation Records Session 8 PDF

Jaw Relation Records Professor Nikolai Attard Session 8 1 1. 2. Remember, it is the record bases and wax Occlusal rims that give us the ability to go from the edentulous mouth to the articulator t...

Jaw Relation Records Professor Nikolai Attard Session 8 1 1. 2. Remember, it is the record bases and wax Occlusal rims that give us the ability to go from the edentulous mouth to the articulator to the final dentures. 3. 4. 2  The Functions of Occlusal Rims is to establish: 1. The Arch Form for both jawbones 2. The Occlusal Vertical Dimension 3. Level of Occlusal Plane 4. Neutral Zone 5. The Esthetic Guidelines 6. Preliminary Maxillomandibular Relations 7. Facebow Record (if dentate) Please note that there is no scientifically established method 3 We are aided in this process by wax occlusion rims placed on record bases. These wax occlusion rims help us orient the two models Provide information as to the placement of the teeth on the dentures for the patient 4  Establishing the Records Design the arch form for the mandibular and maxillary occlusal rim (neutral zone) Establish the height of the occlusal plane of the mandibular rim Modify the level of maxillary rim to meet the mandibular rim at the desired VDO Make a preliminary centric relation record 5  Establishing Arch Form Aims are to determine width of occluding surfaces and contour of the arch so as to establish neutral zone The stable position of the natural dentition is reproduced Same forces that stabilized natural teeth will stabilize the dentures Allows correct positioning of teeth 6  The Neutral Zone The musculature and teeth/dentures are in a stable and harmonious position 7 This series illustrates that the record base and wax occlusal rim only serve to “replace” the teeth that used to be present. This analog for the teeth allows us to obtain jaw relationship records. 8  The mandibular arch form Rim should be designed as per teeth position Anterior- more labial resorption Premolar area- equal loss on buccal and lingual Molar area- more lingual than buccal 9  The mandibular arch form Anterior area should offset labial resorption BUT COMPENSATE FOR MENTALIS MUSCLE Position of canine and premolars should be at the level of the modiolus Therefore setup will be approx labial to crest of ridge In anterior area sometimes teeth are set up on or lingual to crest of ridge Posterior teeth should be on or lingual to crest of ridge 10 The lower wax occlusal rim is adjusted to provide the Plane Of Occlusion for the mandibular arch. Typically, it is made slightly taller than necessary and adjusted with a hot instrument after trying in the mouth. This will be discussed shortly 11  The maxillary arch form Optimal tooth position is important for speech and esthetic purposes Bone reduction is more on labial and buccal Therefore teeth should be labial and buccal to the residual ridge to provide labial support Posterior teeth Should be buccal to ridge Smile implications Also guided by mandibular teeth 12 The role of the incisive papilla 1. Canines Tips are ± 1mm anterior to center of the incisive papilla 2. Teeth set up through a coronal line passing through posterior of papilla Center of Incisive Papilla Edge of Central Incisors 8-10mm labial 13  Adjusting the Maxillary Rim Maxillary rim should meet the lower evenly Anterior part of the rim- at the level of the upper lip or 1-2mm lower than it Lower lip should gently touch the upper rim when we pronounce “F”- eg fifty to fifty five..fenek... Provide labial support- NB if you increase support more tooth structure will show Make sure plane is parallel to interpupillary line 14 Here again, the maxillary wax occlusal rim serves as our analogue for the teeth which are not present in this patient. It is this analogue that allows us to obtain jaw relationship records as well as determine facial support for the placement of the teeth on the subsequent denture. 15 Similarly, the maxillary wax occlusal rim is constructed ahead of time and adjusted as necessary with the patient in the chair. Appropriate lip support and “tooth display” are evaluated. Part of the evaluation of the upper and lower wax occlusion rims is the determination as to whether the chin-nose distance is appropriate for the patient. This brings us to the discussion of Vertical Dimension Of Occlusion. 16 PRP= Physiologic Rest Position OVD(VDO)= Vertical Dimension of Occlusion ID= Interocclusal Distance or Freeway Space 17  A B At Physiologic Rest Position, the upper denture (A) and lower denture (B) do not have the occlusal surfaces of their respective teeth in contact. This slight space between the occlusal surfaces is the Inter-occlusal Distance. 18 This variety of facial images gives some idea of the variation one may see when determining the Physiologic Rest Position with patients of different ages and facial types. 19 The wax occlusal rim is also evaluated for the appearance and position the replacement teeth will eventually occupy. The more skill the operator develops in contouring the wax rim, the less adjustment will be necessary once the teeth are tried in for the esthetic verification. 20  Level of Occlusal Plane First reconcile tongue function with mand denture stability and occlusal plane Occlusal table is bound 1. Lingually by tongue 2. Buccally by buccinator 3. Distally by pterygomandibular raphe 4. Mesially by contraction of mouth- modiolus position Contraction of buccinator presses modiolus to premolars, thereby closing off the occlusal table Food is crushed by the premolars & molars and does not escape at the corner of mouth unless there is VII Cranial nerve damage (Bell’s palsy) or there is compromised neurological function (Parkinson’s) 21  Level of Occlusal Plane Mark corner of mouth on the mand OR This will determine heigth of first premolars Retromolar pads are relatively stable landmarks Mandibular first molar is usually at a level corresponding to ½ to 2/3 of retromolar pad Join anterior and posterior determinants by melting the wax ½ to 2/3 up retromolar pad Modiolus 22  Vertical relations Mechanical methods: e.g. Pre-extraction records, mounted casts of teeth, current dentures,ridge parallelism Physiological methods: Physiological rest position Phonetics Swallowing Esthetics 23 Physiological Rest Position Methods RVD= VDO + Freeway space Get pt into RVD by asking pt to wet lips and relax- if you part lips you should find that there is space Freeway space is 2- 4mm in the premolar area RVD is not completely reliable since it has been shown to change with establishment of new VDO 24  Phonetics S sound brings the anterior teeth close together (like VDO) If inter- rim distance is too great it means that VDO is too small If rims are actually touching together than VDO is too much 25  Phonetics Phonetic Test 1. Hum "M" 2. Labio-dental- F sound count 50-60 3. Minimum speaking distance -Sibilant sounds ("s", "z", sh", ch") 4. Closest Speaking Space Confirms OVD Rims should be at least 1 mm apart 26  Swallowing The teeth come together with a very light contact at the begining of the swallowing cycle If there is no denture occlusion during swallowing, VDO is inadequate Not a completely accurate method 27  Ridge Relations Not relevant for extreme resorption Parallelism of ridges- its a natural process If teeth are lost gradually- ridges will not resorb at the same rate... Measurement of the former dentures correlate measurements with facial features 28  VDO evaluation: Overall facial appearance: adequate height, collapsed or overstretched? Freeway space at rest Measurement of freeway space “S” sound- edges of rims should nearly touch NB RIMS DO NOT CONTACT During S- posteriorly rims should be 1-3mm open. For class II pts it will be more and for class III it will be less 29 Establishing Horizontal Relation 30  Centric Relation Various definitions are present However CR is determined by TMJ not teeth Terminal hinge axis can be determined clinically since it is a jaw movement record There is no mandibular translation 31  Mandibular Movements in the Sagittal Plane CO= Centric Occlusion B= Centric Relation B-C= Rotation (terminal hinge movement) C-D=Translation D= Maximum Opening D-E= Protrusive Closure E= Maximal Protrusion with tooth contacts H= Habitual closure PR= Postural rest position 32 Establishing the Horizontal Relation Interocclusal records- Static- by means of wax beads Graphic- intra or extra oral tracing devices are used Functional- pantographic tracing 33  Static Method Groove the maxillary rims in the molar areas Insert upper rim in mouth Gently groove lower rim in same areas and fill these areas with the registration wax Insert mand rim and stabilize it in position Guide & maintain patient in Centric record position 34  Static Method Rehearse prior to transfering record Make sure that no area other than the occlusal table are touching “itfa’ ilsienek lura u igdem fuq is-snien ta’ wara” Most often preliminary record is inaccurate- do not get discouraged.. Practice makes perfect... 35 Centric Relation Record With no teeth present to provide “indexing” capabilities, grooves are placed in the wax. The soft recording material used in the arch opposite the grooves will pick up the shape of the groove and provide the necessary orientation of the two record bases. 36 Centric Relation Record With no teeth present to provide “indexing” capabilities, grooves are placed in the wax. The soft recording material used in the arch opposite the grooves will pick up the shape of the groove and provide the necessary orientation of the two record bases. 37  This occlusal registration allows us to mount the mandibular cast on the articulator in the same orientation that the mandible has with the maxilla in the patient. We can now start to select and then arrange the replacement teeth on the denture. 38 Materials Available To Record CR : Aluwax PVS Materials (Blue mousse, Stat B-R, etc) There are a variety of materials which may be used for the recording of the jaw to jaw relationship as listed above. The choice of material is dependent on physical properties and ability of the clinician to work with the material. 39 40  Centric Occlusion is the occlusion of opposing teeth in centric relation position May/ not coincide with 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 41  Complete denture occlusion Maximum intercuspation coinciding with CR OR Having a range of contact around CR (Freedom in Centric or Long Centric) 42  Thank you! For any questions: Contact me via email: [email protected] Phone: 23401876 Or wait for the tutorial that will be organised to discuss the lecture 43