1. Biological considerations of orientation, vertical and horizontal jaw relations in complete denture- Second part

2. Short Learning Objectives
1. Definition of Horizontal relation 2. Importance and Significance 3. Method of recording

3. Centric relation GPT 4, BOUCHER
The horizontal jaw relation when the condyles are in the most posterior, unstrained position in the glenoid fossa at any given degree of jaw separation from which the lateral movements can be made.
BOUCHER
The most posterior relation of the lower to the upper jaw from which lateral movements can be made at a given vertical dimension .

4. GPT- 8 definition
The maxillomandibular relationship in which condyles articulate with the thinnest avascular portion of their respective disc with the complex in the anterior superior position against the slopes of articular eminences.
. This position is independent of tooth contact.
. This position is discernible when the mandible is directed superiorly and anteriorly.
. It is restricted to a purely rotary movement about the transverse horizontal axis.

5. Importance of centric relation
Centric relation is a reproducible and stable and comfortable position.Therefore it is used as a reference when mounting dentulous and edentulous casts in articulator.Thus CR serves as a reference relationship for establishing an occlusion.
When CR and CO of artificial teeth do not coincide the stability of denture bases is in jeopardy and patient will have unnecessary pain or discomfort.

6. 3 primary requirements:
To record the correct horizontal relationship of mandible to maxilla
To expert equalized vertical pressure
To retain record in undistorted condition until the cast have been accurately mounted on articulator

7. SIGNIFICANCE
In case of dentulous patients proprioceptive impulses are obtained from PDL.
In case of edentulous patients centric relation act as proprioceptive centre to guide occlusal movements.

8. SALIENT FEATURES: 6 R 1- Retruded 2. Repeatable 3. Recordable 4
SALIENT FEATURES: 6 R 1- Retruded 2. Repeatable 3. Recordable 4. Reproducible 5. Point of return 6. Point of reference.

9. Effective manipulation of mandible requires delicacy and firmness.
METHODS FOR ASSISTING THE PATIENT TO RETRUDE THE MANDIBLE.
Relaxing the jaw and closing
Repeatedly protruding and retruding the mandible
Swallowing and closing
Tapping the rims or back teeth repeatedly
Touching the tip of the tongue to the posterior aspect of the palate or denture border and bite.
Palpate the temporal and massater muscles to relax them.

10. METHODS TO RECORD CENTRIC RELATION:
Physiological or tactile or inter occlusal check record method
FUNCTIONAL
Needle house method
Patterson method
GRAPHIC
Intra oral
Extra oral

11. Physiologic method Based on: Proprioceptive impulse of patient
Kinethetic sense of mandibular movement
Visual acuity and sense of touch of patient
Technique is divided into two steps in edentulous condition-
• Tentative records using occlusion rims attached to accurate stable record bases.
• Inter occlusal check records with the teeth arranged for try in.

12. INDICATIONS
Abnormally related jaws.
Displaceable flabby tissue.
Large tongue
Uncontrolled mandibular movements.
In patients already using a complete denture

13. Material used
Waxes: low fusing
Impression compound
Dental plaster
ZnOE paste

14. PROCEDURE Recording tentative jaw relation:
Maxillary occlusal rim inserted to patients mouth.
Vertical dimension at rest is established.
Mandibular occlusal rim inserted and reduced accordingly,
Using base plate wax, make a tentative CR record by having the patient retrude close the jaws until he feels the closure to be at tentative vertical dimension of jaw separation.

15. b) Making the inter occlusal check record.
Upper and lower trial dentures are inserted into the mouth. Do not let the patient make tooth contact. If premature tooth contact exists with the jaws in centric relation, the patient’s proprioception may not direct the return to this identical position.
Aluwax is added on the occlusal surface of teeth of mandibular occlusal rim
Patient asked to retrude mandible and close on the wax till tooth contact occurs.
Trial dentures removed and allowed to cool.

17. Functional method
Method utilize the functional movements of jaws to record the centric relation.
Patient asked to perform border movements such as protrusive and lateral excersion movement.
Needle house method
Fabrication of occlusal rim made from impression compound
Four metal beads or styli are embedded into premolar and molar areas of maxillary occlusal rim.
Occlusal rim inserted into patients mouth and asked to close occlusal rim and make protrussive,retrussive ,right and left movement of mandible.
When movements are made “diamond shaped marking pattern rather than a line is formed on the mandibular occlusal rim.

18. Patient produces mandibular movements by moving mandible to protrusion , retrusion, right and left lateral

20. b)Patterson method
Occlusal rim made of modelling wax.
In trench or trough is made along the length of mandibular occlusal rim.
A mixture of carborundum and dental plaster is loaded into the trench.
Perform mandibular movement till predetermined vertical dimension.
Movement generates compensative curves in plaster

22. Graphic method
The graphic method record a tracing of mandibular movements in one plane
2 types:
Arrow point tracing
Pantograph
Arrow point tracing is a graphic record measured across single plane
Pantogaph is measured three dimensionally.

24. Factors to be considered while carrying out tracing
Stability of denture base
Resistance of rims
Difficulty in placing central bearing device
Height of residual alveolar ridge
Tongue interference
Efficiency of recording device
Lack of coordinated movements

25. Made using gothic arch tracers
Recorded in horizontal plane.
Consists of central bearing device:a device that provide central point of bearing or support between the maxillary & mandibular dental arches.
consists of contacting point attached to one dental arch and plate attached to opposing dental arch
Plate provide surface on which the tracing of mandibular movements is recorded.
Consists of: CENTRAL BEARING POINT & CENTRAL BEARING PLATE.

29. TYPES OF ARROW POINT TRACERS:
INTRA ORAL TRACING POINT:
Central bearing device is located intra orally.
Tracer is placed within the mouth.
Central bearing point & plate is inserted into patients mouth.
Central bearing point is adjusted such that it contact the central bearing plate at predetermined vertical dimension.
Ask to make anteroposterior and lateral movements.
Central bearing point will draw the tracing pattern on central bearing plate
Tracing should resemble an arrow point with a sharp apex.

31. 2)EXTRA ORAL POINT TRACER:
Concept similar to intra oral tracer.
Additionally have an attachment that project outside mouth.
Record bases attached to recording devices inserted in patients mouth.
Central bearing point is retracted to conduct training exercises.
Recording plate which projects extra orally is coated with precipitated chalk and denatured alcohol.
Patient asked to perform all movements.
Examine for sharp apex.

35. ECCENTRIC JAW RELATION
“any relationship of mandible to maxilla other than centric relation”
Include protrusive and lateral relations.
Help to adjust the lateral and horizontal condylar inclination in the articulator.
Thus helps the articulator to reproduce eccentric movements of mandible and establish balanced occlusion.
Recorded using functional or tactile method.

36. Take home message….
Correct recording of Jaw relation records are very essential for successful fabrication of complete denture. Failure to record properly will ultimately lead to failure of prosthesis.

37. Multiple Choice Questions
1. Free way space is-
A. VDR-VDO
B. VDO-VDR
VDR- IOD
VDO+IOD

38. 2. Face bow helps to record-
Vertical Jaw Relation
Horizontal Jaw Relation
Orientation Jaw Relation
Centric Relation

39. 3. Which of the following is not the type of Face bow-
Kinematic
Fascia
Ear Piece
Condyle

40. 4. Average InterocclusaL distance is-
1-2mm
2-3mm
1-3mm
2-4mm

41. 5. Face bow is helpful when change is expected in-
Vertical Jaw Relation
Horizontal Jaw Relation
Orientation Jaw Relation
Centric Relation

42. 6. Point taken during recording orientation jaw relation are-
3-2 anterior and 1 Posterior
3- 1Anterior and 2 Posterior
4-2 anterior and 2 Posterior
2- 1Anterior and 1 Posterior

43. 7. Graphic method is used to record-
Vertical jaw relation
Horizontal jaw relation
Orientation jaw relation
Physiological jaw relation

44. 8. According to newer definition, centric relation is-
RUM MS AS
SUM

45. 9. Patterson method, which is used to record centric relation, is-
Physiological method
Functional method
Graphic method
Radiological method

46. 10. Which of the following is not the feature of centric relation-
Retruded
Repeatable
Recordable
rechargeable