16. Hobo-twin stage by indrajeet.pptx

7/21/2019 16. Hobo-twin stage by indrajeet.pptx

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Good Morning


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Good Morning


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OCCLUSAL SCHEMES

1. BALANCED ARTICULATION

. !ROUP "UNCTION

#. MUTUALL$ PROTECTEDARTICULATION


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1. BALANCED ARTICULATION

Bi%atera%& 'i(u%taneou'& anterior and)o'terior occ%u'a% contact o* teet+ incentric and eccentric )o'ition'

!PT,-


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. !ROUP "UNCTION

SCHU$LER 1/0/

!PT 0, Mu%ti)%e contact re%ation'etween t+e (a2i%%ar3 and(andiu%ar teet+ in %atera%(o4e(ent' on t+e wor5ing 'ide&w+ere3 'i(u%taneou' contact o*'e4era% teet+ act a' a grou) todi'triute occ%u'a% *orce'.

UNILATERAL BALANCED OCCLUSION


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#. MUTUALL$ PROTECTEDARTICULATION

Stuart 8 Sta%%ard 9 1/0:

An occ%u'ua% 'c+e(e in w+ic+ t+e)o'terior teet+ )re4ent' e2ce''i4econtact o* t+e anterior teet+ in(a2i(u( intercu')ation and t+eanterior teet+ di'engage t+e)o'terior teet+ in a%% (andiu%are2cur'i4e (o4e(ent'.


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Mutua%%3 )rotected occ%u'ion i'con'idered e't ;except in fewclinical conditions< a(ong a%% t+ree

occ%u'ua% 'c+e(e' 9 because itinduces disocclusion


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DISOCCLUSION

Se)aration o* o))o'ing teet+ duringeccentric (o4e(ent' o* (andi%e.


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Why disocclusion.?


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Disocclusion provides "Security insurance"to protect teeth from harmful effects due toa cuspal interference.


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An interference can be caused by a differencebeteen the eccentric and returning condylarpaths.


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Mechanism of Disocclusion


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Mechanism of Disocclusion!


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#ere the condylar and incisal paths areparallel$ and the cusp angle of ma%illary and

mandibular molars is also parallel to boththe condylar and incisal paths. n this case$ during the protrusive

movement the mandible does not rotatearound the intercondylar a%is but onlytranslates.

Since ma%illary and mandibular molarsslide in contact during eccentric movement$disocclusion does not occur


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When the cusp angle is parallel to thecondylar path but the incisal path is

steeper than the condylar path$ themandible translatesand rotates around theintercondylar a%is.

n this case$ the ma%illary and mandibularmolars disocclude. &he component of disocclusion occurring

hen the incisal path is steeper than thecondylar path is referred to as the"anterior guide component" of themechanism of disocclusion.


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When the condylar and incisal paths areparallel and the cusp angle is shalloer than

the condylar path$ the mandible does notrotate around the inter condylar a%is' itonly translates.

#oever$ since the cusp angle is shalloerthan the condylar path$ the ma%illary andmandibular molars disocclude.

&hus$ the component influencing the amount

of disocclusion hen the cusp angle isshalloer than the condylar path isreferred to as the "cusp shape component."


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Mechanism of Disocclusion!(


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When the incisal path is steeper than thecondylar path and the cusp angle is

shalloer than the condylar path$ themandible translatesand rotates aroundthe intercondylar a%is.

)y the additive effect of the anteriorguide component and the cusp shapecomponent$ the ma%illary and mandibular

molars disocclude idely.&his condition is often seen inhealthy individuals


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nfluences on the amount ofdisocclusion

&he three factors that determine

disocclusion$ condylar path$ incisal path and

cusp angle.


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*ondylar path +

&he path travelled by the mandibularcondyle in the &M, during variousmandibular movements


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Deviation of the condylar path

-esults of (arious study by Mc*ollum$ Stuart$ Daason and others

the deviation as

/01in protrusive and 201 in lateralcondylar movements.


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(arious studies shoed clearly that thisdifference shoed consistency ithin each

sub3ect and the returning condylar pathalays passed above the eccentric condylarpath.


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-arely did both paths superimpose. 4o

single case as discovered here theeccentric condylar path e%isted above thereturning condylar path

&he difference found beteen eccentricand returning condylar paths supports the

undeniable fact that "the condylar path isnot fi%ed but is changeable."


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REASON SUPPOSED TO BE

"OR THIS COND$LARDE=IATION


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#obo thought the condylar path deviationsere due to 5buffer spacing5 hich e%istsin the glenoid fossa .

Since the temporo mandibular 3oint issub3ect to strong mechanical stress$ the5buffer spacing5 allos condylar mobility

and helps prevent transmission of directstress to the articular eminentia acrossthe articular dis6.


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f 5buffer spacing5 does not e%ist and thecondyle transmits strong stresses$ thedis6 could not ithstand direct forces and

ould result in damage such as anteriordis6 displacement or a dis6 perforation.

&hus 7)uffer spacing5 is necessary for thecondyle and articular dis6 to functionsmoothly.


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BU""ER SPACE

>.(( 9 centric

>.#(( 9 wor5ing 8 >.0((di'occ%u'ion

>.6(( 9 a%ancing 8 1.>((di'occ%u'ion

>.6(( 9 )rotru'i4e 8 1.1((di'occ%u'ion

So (o%ar '+ou%d di'occ%ude (oret+en t+e u?er ' ace (ini(a% to


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Mu'c%e' re%ated to eccentric(o4e(ent' 9 Latera% Pter3goid And

Diaga'tric Mu'c%e re%ated to o)ening

(o4e(ent' 9 Ma''ater& Te()ora%&

Media% Pter3goid

So*t ti''ue )re'ent etween cond3%e

and g%enoid *o''a 9 1. Re%a2 duringeccentric (o4e(ent'

. contract'

during returning (o4e(ent'.

fl f h *84D9:A-


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nfluence of the *84D9:A-path on the amount of

disocclusion 1> DECREASE IN COND$LAR

INCLINATION IN SA!ITAL PLANE,

1. >.>(( )er degree in )rotru'i4e

. >.>10(( )er degree on nonwor5ing'ide

#. ,>.>>(( )er degree on wor5ing'ide.


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ncisal path +

T+e in@uence o* t+e contacting 'ur*ace o*(a2i%%ar3 and (andiu%ar anterior teet+ in(andiu%ar (o4e(ent'.

nfluence of the incisal path on the


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nfluence of the incisal path on theamount of disocclusion

&he ratio of the influences of condylar and incisalpaths as

/+2 during protrusive movement'

1.12mm;1.10


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&he incisal path influences disocclusion

more than the condylar path. #oever$ theincisal path cannot be used as the soleguiding factor for occlusion.


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Accord. To 5e%%3 et a%

1. =ertica% o4er%a) 9 -.-7

. O)en ite 9 .07

#. Ang%e c%a'' II 9 /.7

. C%a'' III 9 >.67

TOTAL >7 ;a))ro2.0(( onnon,wor5ing 'ide o* )o'terior teet+

T+o(a' , w+en (a2i%%ar3 and(andiu%ar cu')id wi%% +a4e ti) to ti)re%ation in during %atera% (o4e(ent'&t+e (o%ar '+ou%d di'occ%ude 1((.

Hoo 9 1. )rotru'i4e, 1.>-((

. wor5ing, >.-((

#. non wor5ing, 1.1>((

NEED FOR DEVELOPING


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NEED FOR DEVELOPINGTWIN STGE PRO!ED"RE

Denti't cannot (ea'ure t+e returningcond3%ar )at+ o* a )atient.


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Twin-stage procedure


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T+e Twin,'tage )rocedure i' eenrede4e%o)ed a'ed on Twin,ta%e

tec+niue& initia%%3 de'cried 3 Hoo.

A' a re'u%t o* inten'i4e inno4ati4e

'tud3 t+e3 were a%e to )roduce)reci'e di'occ%u'ion wit+out t+e(ea'ure(ent o* cond3%ar )at+

T+i' )rocedure )ro4ide' t+e (ean' tocontro% t+e a(ount o* di'occ%u'ion

w+ic+ wa' not )o''i%e 3 ot+er


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&he mandible can be analogous to an invertedtripod BGuichet /CC. &he posterior legs are

right and left condyles and the anterior leg isthe incisal point.

&he condylar path as unchangeable in a living

body but the anterior guidance could be changedfreely by the dentist.

Anterior guidance influences one ape% of themandibular triangle and is very importantbecause it helps produce disocclusion.


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T+i' new )rocedure +a' eende4e%o)ed to re)roducedi'occ%u'ion and anterior guidance

(ore )reci'e%3 and 'cientica%%3and i' a'ed on 'cientic data and(at+e(atica% ana%3'e' o*

(andiu%ar (o4e(ent.


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-eEuisites of an articulator for

&in stage techniEue

&h f ll i th th 5 it i


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&he folloing are the authors5 ne criteriafor selection of an articulator+

/. An articulator must have a straightsagittal condylar path.

2. An articulator reproduces either one of

the sagittal protrusive and nonor6ingside lateral condylar path inclinations$ butdose not necessarily reproduce Fisher5sangle.


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0. &he immediate mandibular translationdoes nothave to be reproduced.

>. &he )ennett angle is fi%ed at /=degrees.

=. &he or6ing side condylar path musttranslate straight outard along the

transverse horiontal a%is.

A ti l t d t d d


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. An articulator does not need a curvedanterior guide table.

C. &he anterior guide table should beshaped li6e a triangular gutter and bead3ustable for both sagittal inclination

and lateral ing angles.

ro a t3 o u' ng o o


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ro a t3 o u' ng o oConce)t wit+ HANNAU

ARTICULATOR!#allen$es% TO !O"NTER

AIS PLANE u'ed a' a re*erence)%ane

Accord FeinergFit+ an3 o* t+e co((on%3 u'edanterior )oint' o* orientation&t+e degree o* 4ariation )roducedi' in (agnitude o* >.(( at t+e

'econd (o%ar a%ancing cu') 8%e'' anterior%3.


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!&LLENGES

TO !O"NTER

Inci'a% )%ane inc%ination i'0>in condition

I t+in5 we can tr3 5ee)ing inci'a%inc%ination '%ig+t%3 (ore t+en >> t+at

wi%% e c%o'er to 0> and a' it i'aritrar3 4a%ue 'o according to our

%i(itation t+i' on%3 we can do.


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Basic Concept ofTwin-Stage Procedure


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&he cast ith a -emovable anteriorsegment is fabricated.

First$ reproduce the occlusalmorphology of posterior teeth ithoutthe anterior segment and produce a cusp

angle coincident ith the standard valuesof effective cusp angle Breferred to as"*ondition / ".


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Secondly$ reproduce anterior morphologyith the anterior segment and provide

anterior guidance hich produces astandard amount of disocclusionBreferred to as "*ondition 2".

&he application of the to conditionsdescribed to fabricate the cusp angleand anterior guidance are innovative

clinical procedures. &his is named the "tin!stage

procedure."


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*ondition *ondylar

Hath

Anterior

Guide table

Sagittalcondylar

path

)ennettangle

Sagittalinclination

:ateraling

angle

*ondition /

2= /= 2= /1

*ondition2

>1 /= >= 21


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P&'SIOLOGI!LDIS!REPN!'


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!ONTRINDI!TIONS


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Hresently$ tin!stage procedure iscontraindicated in the folloingcases

/ Abnormal curve of Spee

2 Abnormal curve of Wilson0 Abnormally rotated tooth

> Abnormally inclined toot+

h b i di d h


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n the above contraindicated cases$ thevertical a%is of the posterior teeth may

have inclined abnormally. As a result$ theeffective cusp angle may vary to somee%tent even though the cusp angle of a

natural tooth varies minimally. n such condition$ the standard effective

cusp angle presented in the tin!stage

procedure may not be applicable. As aresult$ the occlusion of a restoration maybe inaccurate.


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Step by Step clinical procedure

( !O*PLETE DENT"RE


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() !O*PLETE DENT"REPROST&ESIS

*ondition *ondylar

Hath

Anterior

Guide table

Sagittalcondylar

path

)ennettangle

Sagittalinclination

:ateraling

angle

*ondition /

2= /= 2= /1


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Since all the teeth are to be restored

/.&he cuspal angle and the anterior

guidance can be created precisely ithoutthe concerns about the remaining natural

teeth.

2.&he amount of Disocclusion can be

reproduced precisely as programmed

) F"LL *O"T& RE!ONSTR"!TIO


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*entric relation recorded and

transferred on to the tin #obyArticulator


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Ma%illary cast mounted using hinge bo


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Hrecision of the centric relation recordchec6ed


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Ma6e the anterior segment of the ma%illaryor mandibular cast removable using doelpins. -emove the anterior segment.

HOBOS STAGE I CONDITION: ARTICULATOR


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PROGRAMMING

+,- (,-

+,- (.-


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Wa% the occlusal morphology of theposterior teeth so the ma%illary andmandibular cusps contact during eccentricmovement.

&hus$ a balanced articulation is obtained andevery cusp ill have a standard cusp angle


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&he sagittal condylar path and the anterior guide table is ad3ustedaccording to condition 2


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Wa% the palatal contours of the ma%illaryanterior teeth so the ma%illary and mandibularincisors contact during protrusive movement$

and the ma%illary and mandibular canines onthe or6ing side contact during lateralmovement.


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&hus$ anterior guidance is established andthe standard amount of disocclusion illbe produced.

*eramo!metal copings


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*eramo metal copings


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Face bo transfer for remount procedure$:ucia 3ig is used to ma6e centric relation procedure


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-emount impression registers the occlusal indices

BDone on ma%illary and mandibular teeth


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*hec6 for cuspalinterference


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*ondition 2


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nterfering area is removed chec6ed for even contacts


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Hosterior tooth cemented


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Ma%imum intercuspation andposterior teeth disocclusion


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/) TWIN STGETE!&NI0"E IN !SE OF

GRO"P F"N!TION11


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Group function is indicated hencuspid guidance is absent due to theloss of a canine.

n group function$ the amount ofdisocclusion on the or6ing side during

lateral movement must be ero.


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&he articulator ad3ustment values for

"*ondition 2$" ere values for a mutuallyprotected articulation that produced thestandard amount of disocclusion.

#ence ad3ustment values for"*ondition 2" must be modified. &his can be done by changing the lateral

ing angle of the anterior guide tablefrom 21 degrees to 1 degrees.

For group function .values for


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g pcondition 2

*ondylar path Anterior Guide &able

Sagittal

*ondylarHath

inclination

)ennett

angle

Sagittal

inclination

:ateral

ing angle

>1 /= >= 1

2) Fab3ication of sin$le


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$c3own


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5. Occlusion forOsseo integrated Implants

&he #obo and &a6ayama propose the


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y p p

folloing guidelines based on their clinical

results+/. With natural anterior teeth present and

fi%tures implanted in the molar region$

disocclusion must be created.2. When the fi%tures are implanted in the

anterior region and natural molars are

present$ group function must be created.0.For edentulous cases$ a balanced articulation

must be created.

&ype

of

mplante

d

8cclusal

scheme

B/+condition /

B2 *ondition 2


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Supra

structure

portion

of the

Fi%ture

*ondylar path

ad3ustment values

ncisal guide table

ad3ustment values

Sagittal

nclinatio

n

)ennett

angle

Sagittal

nclinatio

n

:ateral ing

angle

B/ 2 B/ 2 B/ 2 B/ B2

Identulous Hosterior

Area

MHA 2= >1 /= /= 2= >= /1 21

Anterior

area

GF 2= >1 /= /= 2= >= /1 1

*om lete Anterior )A 2= 2= /= /= 2= 2= /1 /1


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&h 6 9

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16. Hobo-twin stage by indrajeet.pptx