Slide 1
Horizontal jaw relationsVinay PavanKumar . K1st year MDS studentDepartment of ProsthodonticsAECS Maaruti Dental College
Horizontal jaw relationCentric relationClinical protocolEccentric relationProtrusive Lateral TheoriesMethods of recordingFunctional Physiological Graphic
Jaw RelationIt is described as any spatial relationship of the mandible to the maxilla
Horizontal jaw relation
Horizontal Jaw relation is the relationship of the mandible to the maxilla in a horizontal plane or it is the relationship of the mandible to the maxilla in an antero-posterior direction.
Centric relation
Eccentric relation
Protrusive relationLateral relationLeft lateral Right lateral
It can be of two types
Centric relation
The most retruded relation of the mandible to the maxilla when the condyles are in the most posterior unrestrained position in the glenoid fossa from which lateral movements can be made, at any given degree of jaw separation.
GPT-8
A maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective disks with the complex in the anteriorsuperior 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 about a transverse horizontal axis.
Purpose of recording centric relationIt is a bone to bone relation and it is constant
It is repeatable and recordable and thus serves as a reliable guide for developing centric occlusion in complete dentures
It is related to the terminal hinge axis ,in CR condyles exhibit pure rotation without any translation
Functional movements like chewing and swallowing can be carried out since it is the most unstrained position. Final act of masticatory stroke ends in centric relation
Reference relation
It is more definite than vertical relation since it is independent of tooth contact
Criterias for mandible to be in centric
Disk properly aligned on both condylesCondyle-disk assembly at the highest point against the posterior slopes of eminentiaMedial pole of condyle-disk assembly braced by bone
Theories of centric relation
The Muscle theory
The Ligament theory
The Osteofiber theory
The Meniscus theory
Saizer P. Centric relation and condylar movement: anatomic mechanism. J Prosthet Dent 1971;26(6):581-91.
The Muscle theoryDefense reflex
External pterygoid muscles contracts
Halts the jaw
The Ligament theoryBind the elements of the articulation
Lateral radiographic views
Suspended or Floating condyle
Anatomic arrangement- not well suited to halt retrusive movement
The Osteofiber theoryMeyer
Fibrous stop - buffer
Retroarticular cushion
retrusive terminal stop
The Meniscus theoryThe posterosuperior surface unfolds along the roof of the glenoid fossaDiscs with their retromeniscal fibrous tissues--stop the retrusive condylar movements
Factors influencing centric relation recordsThe resiliency of the supporting tissues
Fit of the denture bases
Residual alveolar arch
Saliva
Tongue
Yurkstas AA, Kapur KK. Factors influencing centric relation records in edentulous mouths. J Prosthet Dent 2005;93:305-10.
The health and cooperation of the patient
The posture of the patient
The temporomandibular joint and its associated neuromuscular mechanisms
The skill of the dentist
Pressure applied in making the recording
The technique used and the recording devices used
Difficulties in obtaining mandibular retrusion
Biologic difficulties
Mechanical difficulties
Psychological difficulties
Methods of assisting the patient to retrude the mandibleLet the jaw relax, pull it back and close slowly on the posterior teeth
Push the upper jaw out and close on the back teeth
Protrude and retrude the mandible repeatedly
Roll the tongue backwards towards the posterior border of upper denture and close the rims until they meetBissasu M. Use of the tongue for recording centric relation for edentulous patients. J Prosthet Dent 1999;82:369-70.
Boos stretch-relax exercises
Tilting the head backwards
Swallow and close
Recording the Centric relation
Primary requirements -
accuracyequalized vertical pressurerecording medium - uniform consistencyretain the record in an undistorted condition
Pressure used while recording the centric relation
Minimum closing pressure Opposing teeth to touch uniformly and simultaneously at their first contact
Heavy closing pressure To produce same displacement of the soft tissues as on the dentures during function
Methods used for recording centric relationTactile or interocclusal check record method
Functional (chew-in) methodsMeyers methodPattersons methodNeedles-House method
Excursive (graphic) methodsIntraoral tracing Extraoral tracing
Terminal hinge axis method
Other methodsDeglutitionPantography
Tactile or interocclusal check record methodPhilip Pfaff biscuit bitePatients proprioception and tactile sense
Indications:abnormally related jawsexcessively displaceable supporting tissues large tongueabnormal mandibular movementsverify occlusion in existing dentures
Interocclusal check record can be made-Between upper and lower rims
Between upper and lower artificial or natural teeth
Between a central bearing plate and pin
Bite registration/recording materials
WaxesQuick setting plasterImpression compoundBite registration paste (ZnO-E)Bite registration silicone
Technique Two steps-
Tentative records using occlusion rims
Interocclusal check records with the teeth arranged for try-in
Anterior try-inPosterior try-in
Seat the patient with head upright
31Soft tissue position affected by posture.
Nick and Notch method
Too shallow2 mm
Bite registration material
Recording centric relation
Mounting of the casts
Stapler pin method
Functional (chew-in) methodsMeyers methodPattersons methodNeedles-House method
Meyers method
Soft wax - generated pathPlaster index - set the teeth
Pattersons method
Wax occlusal rimsMixture of half plaster and half carborundum in the trenchCompensatory curve
Needles-House method
Compound occlusion rims Four metal styli
Diamond-shaped tracings
Excursive (graphic) methodsGothic arch tracingArrow point tracing
Tracing in one planeApex - the most retruded position
Uses-Verify centric relationObtain protrusive and lateral records
Types-
Intraoral tracerExtraoral tracer
Intraoral tracing assembly
Intraoral tracing
Extraoral tracing (Hight tracing device)
Extraoral tracing
Types of arrow point tracingsTypical
Flat
Asymmetric
Absent apex
Miniature tracing
Double arrow point
Dorsally extended arrow point
Interrupted form
Atypical form
Terminal hinge axis methodAn imaginary line around which the mandible may rotate without translatory movement.
In pure hinge movement49
Other methods-Deglutition PantographyDeglutition
Physiologic methodswallow and hold
Physiologic Centric Relation (Shanahan)Swallow and hold
Shanahan TEJ. Physiologic jaw relations and occlusion of complete dentures. J Prosthet Dent 2004;91(3):203-05.
Verification after denture fabrication30-gauge wax
Shanahan TEJ. Physiologic jaw relations and occlusion of complete dentures. J Prosthet Dent 2004;91(3):203-05.
Centric-relation recording techniquesSwallowing or free closure (Shanahan)Chin point guidanceChin-point guidance with anterior jigBilateral manipulation
Kantor ME, Silverman SI and Garfinkel L. Centric-relation recording techniques-a comparative investigation. J Prosthet Dent 1972;28(6):593-600.
Chin point guidance
Chin-point guidance with anterior jig
Bilateral manipulation
Median variability
Swallowing or free-closure records - 0.40 mmChin-point guidance - 0.14 mm Chin-point guidance with an anterior jig - 0.07 mmBilateral manipulation - 0.05 mm
median variability 0.40--these records deviated 0.40 mm from their mean point.55
Pantography Used clinically to measure mandibular movementGraphic record in three planes
Types-Mechanical (by McCollum and Staurt)Electronic
Pantographic tracings
Eccentric relation recordsProtrusive relation
Lateral relation
Left lateral Right lateral
Protrusive jaw relationRegister the influence of the condylar paths over the movements of the mandible
Christensens phenomenon
Protrusive interocclusal record (Whip mix)
Protrusive interocclusal record (Hanau)
Lateral jaw relations
Influence the intercuspation of teeth in working mastication
Used to program the articulator
Lateral interocclusal records (Whip mix) Set side shift guide at 45o
Mark 6mm from centric relation along Left Lateral tracing and centre the hole of plastic piece over it
Right condylar ball is in protrusion
Side shift guide brought in contact with the ball
Lateral interocclusal records (Hanau)
L = H/8 + 12
( H Horizontal condylar inclination L Lateral condylar inclination)
Clinical protocolNair CK. Programming the semiadjustable articulator. Trends in Prosthodontics 2011;2(1):12-14.
Protrusive records made of plaster at 2mm, 4mm, 6mm, 8mm and 10mm
Nair CK et al. Relationship between protrusive record and horizontal condylar guidance angle. Trends in Prosthodontics 2011;2(1):15-16.
Programming the articulator using interocclusal records to note variation in the condylar guidance angleNair CK et al. Relationship between protrusive record and horizontal condylar guidance angle. Trends in Prosthodontics 2011;2(1):15-16.
Nair CK et al. Relationship between protrusive record and horizontal condylar guidance angle. Trends in Prosthodontics 2011;2(1):15-16. Right condyle( Mean SD)Left condyle ( Mean SD) 2mm 7.083o5.42o 10.42o 7.22o4mm 14.17o 6.56o17.08o 10.97o6mm 18.75o 5.28o 22.5o 8.66o8mm18.33o 3.89o 18.75o 5.69o10mm 11.25o 4.33o 14.58o 5.42o
References:Nair KC, A primer on complete denture fabrication, 1st edition, 2013, Ahuja publication, India Pp 67-77
Winkler S, Essentials of Complete Denture Prosthodontics, 2nd edition, India, A.I.B.T.S Publishers and distributors, 2009, pp 192-201.
Sharry JJ, Complete Denture Prosthodontics, 3rd edition, USA, Mcgraw-Hill Book Company, 1974, pp 215-222.
Manappallil JJ, Complete Denture Prosthodontics, 1st edition, India, Arya (Medi) Publishing House, 2006, pp 145-67, 181-83, 194-98.
Saizer P. Centric relation and condylar movement: anatomic mechanism. J Prosthet Dent 1971;26(6):581-91.
Avant WE. Using the term centric. J Prosthet Dent 1971;25(1):12-15.
Yurkstas AA, Kapur KK. Factors influencing centric relation records in edentulous mouths. J Prosthet Dent 2005;93:305-10.
Shanahan TEJ. Physiologic jaw relations and occlusion of complete dentures. J Prosthet Dent 2004;91(3):203-5.
Kantor ME, Silverman SI and Garfinkel L. Centric-relation recording techniques-a comparative investigation. J Prosthet Dent 1972;28(6):593-600
Kingery RH. A review of sone of the problems associated with centric relation. J Prosthet Dent 1952;2(3):307-19.
Bissasu M. Use of the tongue for recording centric relation for edentulous patients. J Prosthet Dent 1999;82:369-70.
Gothic arch tracing ppt.
Nair CK. Programming the semiadjustable articulator. Trends in Prosthodontics 2011;2(1):12-14.
Nair CK et al. Relationship between protrusive record and horizontal condylar guidance angle. Trends in Prosthodontics 2011;2(1):15-16.
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