44126914-Horizontal-Jaw-Relations[1]

Horizontal jaw relations:

Horizontal jaw relations Phillip pfaff (1756) Called “mush” or “Biscuit” or ”Squash bite”

Classification of Horizontal jaw relations:

Classification of Horizontal jaw relations Centric relation Eccentric relation a) protrusive relations b) lateral relations > left lateral relations > right lateral relations

CENTRIC RELATION:

CENTRIC RELATION Maxillomandibular relationship. Condyles articulate with thinnest avascular portion of their respective disks. Condyle – disk assembly in its most anterior superior position against the slopes of articular eminences. Independent of tooth contacts.

SIGNIFICANCE OF CENTRIC RELATION(CR):

SIGNIFICANCE OF CENTRIC RELATION(CR) CR is more definitive & independent of tooth presence or absence. Recordable & reproducible over a period of time . Serve as reference to established an occlusion. when CR & CO do not coincide, periodontium of natural teeth are endangered & instability of CDs. Helps to detect mounting errors. Accurate CR record properly orient the lower cast to opening axis of articulator & the mandible. Helps in proper adjustment of condylar guidance for the control of eccentric movements of the instrument. rim.

Methods used to record centric relation:

Methods used to record centric relation Tactile / interocclusal check record. functional / chew-in methods. a) Needle house method. b) Patterson’s method. c) Mayer’s method c . Graphic methods. a) Intraoral tracings b) Extra oral tracings D. Terminal Hinge Axis Method.

Methods used to record centric relation:

Methods used to record centric relation E. Other Methods. a) Heating one of the surface of occlusal rim. b) Deep heating or pooling method. c) soft wax / Celluloloid strip is placed over lower rim. d) Soft wax cones are placed over lower rim.

Tactile / interocclusal check record. :

Tactile / interocclusal check record. Can be used to: 1) record CR 2) verify CR on articulators 3) record eccentric relations

Steps In Recording The tactile / Interocclusal Check Record:

Steps In Recording The tactile / Interocclusal Check Record Step # 01: Training the patient Step # 02: Indexing The Rim Step # 03: Recording CR

Bite Registration Materials:

Bite Registration Materials Quick setting plaster Bite registration (ZOE) paste Bite registration wax Bite registration silicone

Requirements of bite registration material:

Requirements of bite registration material Dimensionally accurate after setting. Should be fluid in consistency during rerecording to avoid pressure . Adequate working time Short setting time

Graphic/Excursive/ Gothic Arch Tracing Methods. :

Graphic/Excursive/ Gothic Arch Tracing Methods. USES To obtained the CR record records. Used to verify CR records obtained by other methods. Used to obtained protrusive & lateral (eccentric) records USES

Recording Method:

Recording Method Central Bearing Device: Consist of pair of central bearing plates. The plate attached to maxillary rim contain stylus/ bearing pin. The plate attached to mandibular rim consist of tracing table. The stylus traces an “ ARROW POINT ” corresponding to mandibular movement. To obtained tracing, the tracing plate is painted with some marking substance (carbon, ink, wax) Sharp apex of arrow point represents an accurate centric.

INTRA-ORAL TRACING METHOD:

INTRA-ORAL TRACING METHOD Take the tentative CR record & mount the rims . Attaches the central bearing devices to corresponding rim. Adjust the stylus to obtained its contact to tracing plate at predetermined OVD. Transfer the assembly into the mouth to obtained ‘arrow point’ tracing corresponding to protrusive & lateral movements.

TRANSFERING THE RECORD TO ARTICULATOR:

TRANSFERING THE RECORD TO ARTICULATOR Take 4×6 cm plastic strip ( bur box lid). Drill two hole middle of the strip, 4–to-6 mm gap in between the holes. Fix the strip over the tracing plate in such a way that hole must corresponds to sharp apex of arrow point while other hole must be over the line representing protrusion or lateral movements. Shift the assembly into the mouth guide the mandible into centric till stylus drops into the posterior hole. Pour bite registering material b/w upper & lower wax rims , wait till it sets. Remove & transfer the record to articulator.

DIFFICULTIES IN RECORDING THE CR:

DIFFICULTIES IN RECORDING THE CR BIOLOGICAL DIFFICULTIES; N euromuscular in-coordination. TMJ problems. Bite of convenience. The amount & character of saliva. Maxillo-mandibular relationship ANATOMICAL FACTORS; Resiliency of supporting tissues. Size & position of the tongue. The character & size of residual alveolar ridge

DIFFICULTIES IN RECORDING THE CR:

DIFFICULTIES IN RECORDING THE CR Mechanical Factors; Stability of denture bases. Character of pressure applied in recording the CR. Technique used in making the CR records. Posture of the patient. PSYCHOLOGICAL FACTOR; Anxiety Fatigue Frustration Lake of cooperation

ECCENTRIC RELATIONS:

ECCENTRIC RELATIONS “ANY HORIZONTAL RELATIONSHIP OF MANDIBLE TO MAXILLA OTHER THAN CENTRIC POSITION”

IMPORTANCE OF ECCENTRIC RELATIONS:

IMPORTANCE OF ECCENTRIC RELATIONS ECCENTRIC RELATION RECORDS ARE USED TO PROGRAM AN ADJUSTABLE ARTICULATOR TO SIMULATE THE JAW MOVEMENTS. PROGRAMMING OF ARTICULATOR HELPS TO ESTABLISHED BALANCED OCCLUSION IN A REMOVABLE PROSTHESISIS. HELPS TO ESTABLISHED AN OCCLUSION WHICH IS IN HARMONY WITH THE FUNCTIONAL MOVEMENTS OF THE MANDIBLE.

IMPORTANANT ECCENTRIC RELATIONS:

IMPORTANANT ECCENTRIC RELATIONS a) protrusive relations b) lateral relations > left lateral relations > right lateral relations

Protrusive Relations :

Protrusive Relations THE PROTRUDED JAW RELATION IS THAT WHERE MANDIBLE CAN BE PROTRUDED TO A POSITION ANTERIOR TO THAT OF CR. PROTRUSIVE JAW RECORDS HELPS TO PROGRAM HORIZONTAL CONDYLAR GUIDANCE. ALSO HELPS TO PROGROM LATERAL CONDYLAR GUIDANCE. “CHRISTENSEN ’ S PHENOMENON”

METHODS TO OBTAINED PROTRUSIVE RECORDS:

METHODS TO OBTAINED PROTRUSIVE RECORDS A. Tactile / interocclusal check record. B. functional / chew-in methods. a) Needle house method. b) Patterson’s method. c) Mayer’s method c . Graphic methods. a) Intraoral tracings b) Extra oral tracings

Lateral jaw relations:

Lateral jaw relations The relation of mandible to maxilla when it is moving to left or right of CR . Site to which the the mandible is moving is called ‘WORKING SITE’, representing characteristic “ BENNETT SHIFT”. Site from where mandible is moving is called ‘BALANCING SITE’, representing characteristic “ BENNETT MOVEMENT”. Used to program the ‘lateral condylar guidance’. Hanau semi-adjustable articulators do not accept lateral relation records.

METHODS USED TO RECORD LATERAL JAW RELATIONS :

METHODS USED TO RECORD LATERAL JAW RELATIONS Lateral check records Graphic method Hanau’s formula (1930) L = H/8 +12 Where L = lateral condylar inclination H = Horizontal condylar inclination