Horizontal jaw relations

Vinay PavanKumar . K1st year MDS student

Department of ProsthodonticsAECS Maaruti Dental College

Horizontal jaw relation

Centric relation

Clinical protocol

Eccentric relation

Protrusive

Lateral

Theories

Methods of recording

Functional

Physiological

Graphic

Jaw Relation

• It 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 relation• Lateral relation

• Left 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 relation

• It 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 condyles

• Condyle-disk assembly at the highest point against the

posterior slopes of eminentia

• Medial 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 theory

Defense reflex

External pterygoid muscles contracts

Halts the jaw

The Ligament theory

• Bind the elements of the articulation

• Lateral radiographic views

• ‘Suspended’ or ‘Floating’ condyle

• Anatomic arrangement- not well suited to halt retrusive movement

The Osteofiber theory

• Meyer

• Fibrous stop - buffer

• Retroarticular cushion

• retrusive terminal stop

The Meniscus theory

• The posterosuperior surface unfolds along the roof of the glenoid fossa

• Discs with their retromeniscal fibrous tissues--stop the retrusive condylar movements

Factors influencing centric relation records

• The resiliency of the supporting tissues

• Fit of the denture bases

• Residual alveolar arch

• Saliva

• TongueYurkstas 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 mandible

• Let 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 meet

Bissasu 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 -

• accuracy

• equalized vertical pressure

• recording medium - uniform consistency

• retain 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 relation

• Tactile or interocclusal check record method

• Functional (chew-in) methods• Meyer’s method• Patterson’s method• Needles-House method

• Excursive (graphic) methods• Intraoral tracing • Extraoral tracing

• Terminal hinge axis method

• Other methods• Deglutition• Pantography

Tactile or interocclusal check record method• Philip Pfaff – “biscuit bite”• Patient’s proprioception and tactile sense

• Indications:• abnormally related jaws• excessively displaceable supporting tissues • large tongue• abnormal mandibular movements• verify 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

• Waxes

• Quick setting plaster

• Impression compound

• Bite 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-in• Posterior try-in

Seat the patient with head upright

Nick and Notch method

Too shallow

2 mm

Bite registration material

Recording centric relation

Mounting of the casts

Stapler pin method

Functional (chew-in) methods

• Meyer’s method• Patterson’s method• Needles-House method

• Meyer’s method

• Soft wax - generated path• Plaster index - set the teeth

Patterson’s method

• Wax occlusal rims• Mixture of half plaster and • half carborundum in the trench• Compensatory curve

Needles-House method

• Compound occlusion rims • Four metal styli

• Diamond-shaped tracings

Excursive (graphic) methods

• Gothic arch tracing• Arrow point tracing

• Tracing in one plane• Apex - the most retruded

position

• Uses-• Verify centric relation• Obtain protrusive and lateral records

• Types-

• Intraoral tracer• Extraoral tracer

Intraoral tracing assembly

Intraoral tracing

Extraoral tracing (Hight tracing device)

Extraoral tracing

Types of arrow point tracings

• Typical

• Flat

• Asymmetric

• Absent apex

• Miniature tracing

• Double arrow point

• Dorsally extended arrow point

• Interrupted form

• Atypical form

Terminal hinge axis method

• An imaginary line around which the mandible may rotate without translatory movement.

Other methods-

• Deglutition • Pantography• Deglutition

• Physiologic method• ‘swallow 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 fabrication• 30-gauge wax

Shanahan TEJ. Physiologic jaw relations and occlusion of complete dentures. J Prosthet Dent 2004;91(3):203-05.

Centric-relation recording techniques

• Swallowing or free closure (Shanahan)• Chin point guidance• Chin-point guidance with anterior jig• Bilateral 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 mm• Chin-point guidance - 0.14 mm • Chin-point guidance with an anterior jig - 0.07 mm• Bilateral manipulation - 0.05 mm

Pantography

• Used clinically to measure mandibular movement• Graphic record in three planes

• Types-• Mechanical (by McCollum and Staurt)• Electronic

Pantographic tracings

Eccentric relation records

• Protrusive relation

• Lateral relation

• Left lateral • Right lateral

Protrusive jaw relation

• Register the influence of the condylar paths over the movements of the mandible

• Christensen’s 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 protocol

Nair 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 angle

Nair 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 7.083o±5.42o 10.42o ± 7.22o

4mm 14.17o ± 6.56o 17.08o ± 10.97o

6mm 18.75o ± 5.28o 22.5o ± 8.66o

8mm 18.33o ± 3.89o 18.75o ± 5.69o

10mm 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.