Mereesha.Mereesha.

33rdrd BDS BDS

Dept. of ProsthodonticsDept. of Prosthodontics

CENTRIC RELATION.CENTRIC RELATION.DEFN….(GPT)DEFN….(GPT)

Most accepted.Most accepted.The maxillo mandibular The maxillo mandibular

relationship in which relationship in which condyles articulate with condyles articulate with the thinnest avascular the thinnest avascular

portion of their respective portion of their respective disks with the complex in disks with the complex in anterior superior portion anterior superior portion

against the slops of against the slops of articular eminencearticular eminence

RELATION.RELATION.

CENTRICCENTRIC

CENTRIC RELATIONS.CENTRIC RELATIONS.

CENTRIC RELATIONS.CENTRIC RELATIONS.

DEFN….(GPT)DEFN….(GPT)Most accepted.Most accepted.

The maxillo mandibular relationhip in which condyles The maxillo mandibular relationhip in which condyles articulate wth the thinnest avascular portion of their articulate wth the thinnest avascular portion of their

respective disks with the complex in anterior superior respective disks with the complex in anterior superior portion against the slops of articular eminenceportion against the slops of articular eminence

SIGNIFICANCESIGNIFICANCE

Constant reference in Constant reference in recording centric occlusionrecording centric occlusion..Repeatable reproducable Repeatable reproducable

recordablerecordableStarting and termination Starting and termination any developing occlusion.any developing occlusion.

Chewing swallowing etc are Chewing swallowing etc are performed in this position-performed in this position-most unstrained position.most unstrained position.

REQUIREMENTS…REQUIREMENTS…To record the correct To record the correct horizontal relation of horizontal relation of mandible to maxillamandible to maxilla

To exert equalized To exert equalized vertical pressurevertical pressure

To retain the record in To retain the record in an undistorted condition an undistorted condition

till its mounted. till its mounted.

RECORDING CRRECORDING CR

•Max rim-2or 3 notches & Max rim-2or 3 notches & remove 3mm from remove 3mm from mandibular rim.mandibular rim.

•Lubricate wit petrolatumLubricate wit petrolatum•Place both rims in patient’s Place both rims in patient’s

mouthmouth

• Training movementsTraining movements Index fin-buccal flanges of PM areaIndex fin-buccal flanges of PM area• Thumb – chinThumb – chin• Pt is asked 2 close mouth slowly on back Pt is asked 2 close mouth slowly on back

teethteeth• Soft aluwax is placed on mandibular rim Soft aluwax is placed on mandibular rim

1.5mm above rim-warm water –uniform 1.5mm above rim-warm water –uniform heatingheating

• Place in mouth n guided the pt. to CRPlace in mouth n guided the pt. to CR• Stop when anterior occlusal rim almost but Stop when anterior occlusal rim almost but

not quiet touching the lower-within 0.5mmnot quiet touching the lower-within 0.5mm• Check againCheck again• Other mat.-soft base plate wax, plaster, Other mat.-soft base plate wax, plaster,

bite registration paste.bite registration paste.

Contd……Contd……

• Remove basesRemove bases

• Check againCheck again

• BP wax,plaster,bite reg paste….BP wax,plaster,bite reg paste….

• Mount casts using recordMount casts using record

• Condyle balls of articulator should Condyle balls of articulator should remain flush with their stops.remain flush with their stops.

METHODS TO RECORD CRMETHODS TO RECORD CR

FUNCTIONALa) Needle house tech.

b) Patterson techc) Phonetics-S,F

d) Silverman’s biting pt.e) Mandibulography

f) Relatorg) Boos

h) Gnathodynamo meteri) Myomonitor

j) Myer’s fuctional generated tech

FUNCTIONALa) Needle house tech.

b) Patterson techc) Phonetics-S,F

d) Silverman’s biting pt.e) Mandibulography

f) Relatorg) Boos

h) Gnathodynamo meteri) Myomonitor

j) Myer’s fuctional generated tech

GRAPHIC•EXTRAORAL•INTRAORAL

•PANTOGRAPHIC

GRAPHIC•EXTRAORAL•INTRAORAL

•PANTOGRAPHIC

TACTILE/INTEROCCLUSAL CHECK RECORD•NO PRESSURE

•MINIMAL PRESSURE •HEAVY PRESSURE

TACTILE/INTEROCCLUSAL CHECK RECORD•NO PRESSURE

•MINIMAL PRESSURE •HEAVY PRESSURE

Cephalometric methodsCephalometric methods

FUNCTIONAL(CHEW-IN)FUNCTIONAL(CHEW-IN)

A tentative CR and VD are measured A tentative CR and VD are measured for determining accurate CRfor determining accurate CR

Occlusion rims are reduced in excess Occlusion rims are reduced in excess than required for tentative VDthan required for tentative VD

Record bases should be very stableRecord bases should be very stableInaccuracy due to Inaccuracy due to

•Displaceable basal tissues Displaceable basal tissues •Resistance of recording medium lack Resistance of recording medium lack

control of pressure in eccentric relationscontrol of pressure in eccentric relations•Poor neuromuscular coordinationPoor neuromuscular coordination

NEEDLE HOUSE METHODNEEDLE HOUSE METHOD4 Metal styli on maxillary 4 Metal styli on maxillary

occlusion rimocclusion rim•Movement of mandible Movement of mandible i.e retrusion , protrusion i.e retrusion , protrusion and lateral movements.and lateral movements.

•4 diamond shaped 4 diamond shaped tracings on mandibular rim tracings on mandibular rim

which in cooperate which in cooperate movements in 3 planesmovements in 3 planes•Posterior most point in Posterior most point in

this denote centric relationthis denote centric relation

NEEDLE HOUSE METHODNEEDLE HOUSE METHOD

4 Metal styli on mxillary occlusion rim4 Metal styli on mxillary occlusion rim•Movt of mandible i.e retrusion ,protrusionand Movt of mandible i.e retrusion ,protrusionand

lateral movts.lateral movts.•4 diamond shaped tracings on mandibular rim 4 diamond shaped tracings on mandibular rim

which in coperate movts in 3 planeswhich in coperate movts in 3 planes•Postr most pt in this denote centric relationPostr most pt in this denote centric relation

NEEDLE HOUSE METHODNEEDLE HOUSE METHOD

4 Metal styli on mxillary occlusion rim4 Metal styli on mxillary occlusion rim•Movt of mandible i.e retrusion ,protrusionand Movt of mandible i.e retrusion ,protrusionand

lateral movts.lateral movts.•4 diamond shaped tracings on mandibular rim 4 diamond shaped tracings on mandibular rim

which in coperate movts in 3 planeswhich in coperate movts in 3 planes•Postr most pt in this denote centric relationPostr most pt in this denote centric relation

PATTERSON’S METHODPATTERSON’S METHOD•Trench made on Trench made on mandibular rimmandibular rim

•Mixture of half plaster Mixture of half plaster +half carborandum placed +half carborandum placed

in trenchin trench•Insert in pts mouth and Insert in pts mouth and

make mandibular make mandibular movements-create movements-create

compensating curves in compensating curves in plaster and carborandumplaster and carborandum

•When plaster is When plaster is instructed to retrude and instructed to retrude and occlusal rim are joined by occlusal rim are joined by

staplesstaples

PATTERSON’S METHODPATTERSON’S METHOD

•Trench made on mand rimTrench made on mand rim•Mixture of half plaster +half carborandum placed in Mixture of half plaster +half carborandum placed in

trenchtrench•Insert in pts mouth and make mand movts-create Insert in pts mouth and make mand movts-create compensating curves in plaster and carborandumcompensating curves in plaster and carborandum

•When plaster is instructed to retrude and occl.rim When plaster is instructed to retrude and occl.rim are joined by staplesare joined by staples

PATTERSON’S METHODPATTERSON’S METHOD

•Trench made on mand rimTrench made on mand rim•Mixture of half plaster +half carborandum placed in Mixture of half plaster +half carborandum placed in

trenchtrench•Insert in pts mouth and make mand movts-create Insert in pts mouth and make mand movts-create compensating curves in plaster and carborandumcompensating curves in plaster and carborandum

•When plaster is instructed to retrude and occl.rim When plaster is instructed to retrude and occl.rim are joined by staplesare joined by staples

GRAPHIC METHODGRAPHIC METHOD

ARROW PT ARROW PT TRAINING/GOTHIC ARCH TRAINING/GOTHIC ARCH

TRACINGTRACING

Contd…Contd…Record max-mandibular relations in 1 Record max-mandibular relations in 1

plane.plane.-device used is central bearing tracing -device used is central bearing tracing

devicedevice-device that provides a central point -device that provides a central point

of bearing or support b/w max of bearing or support b/w max &mandibular occlusal rims or dentures&mandibular occlusal rims or denturesContacting pt which is attached to Contacting pt which is attached to

one occlusal rimone occlusal rimPlate attached to other occlusal rim Plate attached to other occlusal rim on which the pointer rests or moves.-on which the pointer rests or moves.-

denatured spirit n chalk powderdenatured spirit n chalk powder

INTRAL ORAL TRACINGINTRAL ORAL TRACING

a)a) Pointer (mand)Pointer (mand)b)b) Plate (max)Plate (max)

Can’t be observed during tracingsCan’t be observed during tracings Small trainings-difficult to find the apexSmall trainings-difficult to find the apex Tracer must be definitely seated in a Tracer must be definitely seated in a

hole at the pt & apex to assure hole at the pt & apex to assure accuracy when injecting plaster b/w accuracy when injecting plaster b/w

occlusal rimsocclusal rims If point moves mandible before occlusal If point moves mandible before occlusal

rims are secured-inaccuraterims are secured-inaccurate

GRAPHIC METHODGRAPHIC METHOD

ARROW PT ARROW PT TRAINING/GOTHIC ARCH TRAINING/GOTHIC ARCH

TRACINGTRACING

INTRAL ORAL TRACINGINTRAL ORAL TRACINGa)a) Pointer(mand)Pointer(mand)

b)b) Plate(max)Plate(max) Can’t be observed during tracingsCan’t be observed during tracings

Small trainings-difficult to find the apexSmall trainings-difficult to find the apex Tracer must be definitely seated in a hole at the pt & Tracer must be definitely seated in a hole at the pt &

apex to assure accuracy whn injecting plaster b/w apex to assure accuracy whn injecting plaster b/w occl.rimsoccl.rims

If pt.moves mand before occl rims are secured-If pt.moves mand before occl rims are secured-inaccurateinaccurate

EXTRA ORAL TRACINGSEXTRA ORAL TRACINGS

a)a) POINTER(MAX)POINTER(MAX)b)b) PLATE(MAND)PLATE(MAND)

• Visible when tracing is madeVisible when tracing is made• Larger tracing than intra oralLarger tracing than intra oral• Stylus can be observed in the Stylus can be observed in the

apex while injecting plaster apex while injecting plaster between occusall rimsbetween occusall rims• No hole requiredNo hole required

EXTRA ORAL TRACINGSEXTRA ORAL TRACINGS

a)a) POINTER(MAX)POINTER(MAX)b)b) PLATE(MAND)PLATE(MAND)

• Visible whn tracing is madeVisible whn tracing is made• Larger tracing than intraoralLarger tracing than intraoral

• Stylus can be observerd in the apex Stylus can be observerd in the apex while injecting popb/w occl rimswhile injecting popb/w occl rims

• No hole requiredNo hole required• Pt can be directed/guided more Pt can be directed/guided more

ntelligentlyntelligently

EXTRA ORAL TRACINGSEXTRA ORAL TRACINGS

a)a) POINTER(MAX)POINTER(MAX)b)b) PLATE(MAND)PLATE(MAND)

• Visible whn tracing is madeVisible whn tracing is made• Larger tracing than intraoralLarger tracing than intraoral

• Stylus can be observerd in the apex Stylus can be observerd in the apex while injecting popb/w occl rimswhile injecting popb/w occl rims

• No hole requiredNo hole required• Pt can be directed/guided more Pt can be directed/guided more

ntelligentlyntelligently

TECHNIQUE FOR GRAPHIC TECHNIQUE FOR GRAPHIC METHODMETHOD

(EXTRA ORAL ARROW POINT (EXTRA ORAL ARROW POINT TRACING USNG HEIGHT TRACING USNG HEIGHT

TRACING DEVICE)TRACING DEVICE)

CONTD…CONTD…1)1) Accurate max-mand record Accurate max-mand record

bases bases 2)2) Occlusal rims of hard base Occlusal rims of hard base

plates waxplates wax3)3) contour the rimscontour the rims4)4) Established VDR at restEstablished VDR at rest5)5) Reduce mandibular occlusal rim Reduce mandibular occlusal rim

–excess inter occlusal distance–excess inter occlusal distance6)6) Face bow transfer &max cast Face bow transfer &max cast

mountingmounting7)7) Tentative CR record with soft Tentative CR record with soft

wax at pre determined VDOwax at pre determined VDO8)8) Adjust articulatorAdjust articulator9)9) Relate max occlusal rim in soft Relate max occlusal rim in soft

wax record and attach wax record and attach mandibular cast to articulator mandibular cast to articulator with plasterwith plaster

1)1) Mount central bearing deviceMount central bearing device2)2) Centralize itCentralize it3)3) Seat pt with head upright relaxedSeat pt with head upright relaxed4)4) Seat recording devices with occlusal rim Seat recording devices with occlusal rim 5)5) Retract stylus and conduct training Retract stylus and conduct training

exercisesexercises6)6) Prepare tracing plate develop acceptable Prepare tracing plate develop acceptable

tracing by movements of mandibletracing by movements of mandible7)7) Tracing with sharp apex-retrude mandible Tracing with sharp apex-retrude mandible

to CRto CR8)8) Inject dental plaster and allow it to Inject dental plaster and allow it to

hardenharden9)9) Remove assembly and mountRemove assembly and mount10)10)Check with IOCR when teeth are arrangedCheck with IOCR when teeth are arranged

THINGS TO BE NOTEDTHINGS TO BE NOTED1.1. If centralizing is not done If centralizing is not done

displacement of record bases displacement of record bases 2.2. Difficult to local the centre of Difficult to local the centre of

archesarches3.3. Difficult to stabilize record Difficult to stabilize record

bases in displaceable bases in displaceable tissues ,in ridges with low tissues ,in ridges with low vertical height, point with large vertical height, point with large tonguetongue

4.4. Not acceptable if blunt apex is Not acceptable if blunt apex is obtained obtained

5.5. Double tracing lack of Double tracing lack of coordinated movements at coordinated movements at different vertical dimensionsdifferent vertical dimensions

Contd…Contd…

•Eccentric jaw relations Eccentric jaw relations

•Most accurate visual means Most accurate visual means

•Helps to harmonize CR & COHelps to harmonize CR & CO

TACTILE OR IOCR METHODTACTILE OR IOCR METHODMATERIALS USEDMATERIALS USED

1)WAX1)WAX -low fusing-low fusing -very little resistance to jaw closure-very little resistance to jaw closure -harden quickly-harden quickly -used when muscle control of -used when muscle control of

mandible is poormandible is poor -easily distorted-error-easily distorted-error

2)COMPOUNDS ,PLASTER,ZNOE2)COMPOUNDS ,PLASTER,ZNOE -some resistance to closure-some resistance to closure -maintain in contact until they are -maintain in contact until they are

hard- otherwise errorhard- otherwise error -break before thy distort especially -break before thy distort especially

plasterplaster -plaster and eugenol preferred when -plaster and eugenol preferred when

non cusp form of teeth is usednon cusp form of teeth is used

TECHNIQUE….TECHNIQUE….

1.1. Tentative records with Tentative records with occlusal rims occlusal rims

2.2. IOCR with teeth arrangedIOCR with teeth arranged

Contd..Contd..

•-seat the patient -seat the patient comfortablycomfortably•-contour maxillary rings -contour maxillary rings and distal cuspid points lip and distal cuspid points lip lines and occlusal planes.lines and occlusal planes.•-measure VDR reduce -measure VDR reduce mandibular rim to allow mandibular rim to allow excess inter occlusal excess inter occlusal distance.distance.•-make a face bow transfer -make a face bow transfer recordrecord

• -using base plate wax record tentative -using base plate wax record tentative CR by retruding mandible until he CR by retruding mandible until he feels the closure to be at tentative feels the closure to be at tentative VDRVDR

• -compare VDO & VDR.-compare VDO & VDR.• -Adjust articulator.-Adjust articulator.• -mount maxillary cast using face bow -mount maxillary cast using face bow

transfer recordtransfer record• -secure CR record to max rim and -secure CR record to max rim and

position mandibular castposition mandibular cast• -attach mandibular cast to articulator -attach mandibular cast to articulator

with plasterwith plaster

STEPS DURING TRY-INSTEPS DURING TRY-IN1.1. Seat the patient Seat the patient 2.2. Seat max record baseSeat max record base3.3. Seat mandibular record baseSeat mandibular record base4.4. -do not let pt make tooth -do not let pt make tooth

contactcontact5.5. -do not fatigue the pt-do not fatigue the pt6.6. Remove mandibular rim and Remove mandibular rim and

train the patienttrain the patient7.7. Dry mandibular posterior teeth Dry mandibular posterior teeth 8.8. Adapt two layers of alu wax to Adapt two layers of alu wax to

occlusal surface of posterior occlusal surface of posterior teethteeth

9.9. -do not entrap air-do not entrap air10.10.Soften wax with controlled or Soften wax with controlled or

130130°F water bath°F water bath

11.11.seat mandibular record baseseat mandibular record base12.12.ask pt to retrude and close back teeth and ask pt to retrude and close back teeth and

stop when contact is madestop when contact is made13.13.Allow wax to harden. Dry.Allow wax to harden. Dry.14.14.Inspect record to see no cusp tip Inspect record to see no cusp tip

penetrate to make tooth to tooth contactpenetrate to make tooth to tooth contact15.15.Remove maxillary record base and place Remove maxillary record base and place

on maxillary caston maxillary cast16.16.Release horizontal condylar guide locks on Release horizontal condylar guide locks on

articulatorarticulator17.17.Place mandibular record base on to the Place mandibular record base on to the

castcast18.18.Carefully seat maxillary teeth in record.Carefully seat maxillary teeth in record.19.19.Observe condylar elements if they rest Observe condylar elements if they rest

against centric stops the record is same as against centric stops the record is same as original if not it is in accurateoriginal if not it is in accurate

Contd..Contd..-seat the patient comfortably-seat the patient comfortably

-contour maxillary rings and distal cuspid points -contour maxillary rings and distal cuspid points lip lines and occlsal planes.lip lines and occlsal planes.

-measure VDR reduce mandibular rim to allow -measure VDR reduce mandibular rim to allow excess inter occl distance.excess inter occl distance.

-make a face bow transfer record-make a face bow transfer record-using base plate wax record tentative CR by -using base plate wax record tentative CR by

retruding mandible until he feels the closure to retruding mandible until he feels the closure to be at tentative VDRbe at tentative VDR

-compare VDO & VDR.-compare VDO & VDR.-Adjust articulator.-Adjust articulator.

-mount maxiilARY cast using face bow -mount maxiilARY cast using face bow transferrecordtransferrecord

-secure CR record to max rim and postion mand -secure CR record to max rim and postion mand castcast

-attach mand cast to articulator wth plaster-attach mand cast to articulator wth plaster

Contd…Contd…

•Eccentric jaw relations Eccentric jaw relations

•Most accurate visual means Most accurate visual means

•Helps to harmonize CR & COHelps to harmonize CR & CO