Dent 343 Lect 9_handout

8/3/2019 Dent 343 Lect 9_handout

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Concepts of Complete DentureConcepts of Complete Denture

OcclusionOcclusion

Dent 343

Lecture No.9

Complete Denture Prosthodontics

Dr Esam Alem

December 1, 2009

Textbook Reference: Chapter 17

Concepts of CompleteConcepts of CompleteDenture OcclusionDenture Occlusion

Mobile bases on mucosa Teeth move as an unit

Malocclusion affects entire baseimmediately

Non-vertical forces affect all teethand is traumatic

Incising affects all teeth attached tobase

Bilateral balance is often desired forbase stability

Decreased tactile sense

Retained in PDL Units move independently

Malocclusion effects notimmediate

Non-vertical forces affect onlyteeth involved and usually welltolerated

Incising doesnt affect posteriors

Bilateral balance is rare Tactile sensitivity

Natural Dentition Denture Dentition

Differences between Natural andDifferences between Natural and

Complete Denture OcclusionComplete Denture OcclusionGoals of Complete Denture OcclusionGoals of Complete Denture Occlusion

Minimize trauma to thesupporting structures

Preserve remainingstructures

Enhance stability of thedentures

Facilitate esthetics andspeech

Restore masticationefficiency to areasonable level


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NATURALNATURAL

VS.VS.

COMPLETE DENTURECOMPLETE DENTUREOCCLUSIONOCCLUSION

Bilateral PosteriorBilateral PosteriorCentric ContactCentric Contact

Anterior GuidanceAnterior Guidance

Mutually ProtectiveMutually ProtectiveScheme of OcclusionScheme of Occlusion

Natural Occlusion(organic)

Complete dentureComplete denture

dentitiondentitionalsoalsopresents in a variety ofpresents in a variety offorms, but also exhibitforms, but also exhibitcertain commoncertain commoncharacteristicscharacteristics

Complete DentureOcclusion

Bilateral centric contactsBilateral centric contacts Bilateral eccentric contactsBilateral eccentric contacts

(balance) to provide stability(balance) to provide stability

of the denture bases duringof the denture bases duringfunctionfunction

NonNon--balanced monoplanebalanced monoplaneocclusionocclusion

Complete DentureOcclusion


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Because of compromisesBecause of compromises

inherent in restoring theinherent in restoring theedentulous arch, completeedentulous arch, complete

denture tooth forms anddenture tooth forms and

arrangements (i.e.arrangements (i.e.

occlusion), should beocclusion), should be

designed to providedesigned to provide

function and aestheticsfunction and aesthetics

while minimizing denturewhile minimizing denturebase tipping (lateral)base tipping (lateral)

forcesforces

Complete Denture Occlusion Fundamental differences of natural andFundamental differences of natural andcomplete denture occlusioncomplete denture occlusion1.1. Sensory feedback mechanismSensory feedback mechanism

2.2. Derivation of :Derivation of : retentionretention

stabilitystability

supportsupport

3.3. Reaction of supporting structures toReaction of supporting structures tomasticatorymasticatory forcesforces

1. Sensory Feedback1. Sensory Feedback

Precision of feedback is significantly compromisedPrecision of feedback is significantly compromised

following loss of teeth and associated structuresfollowing loss of teeth and associated structures

(periodontal ligament)(periodontal ligament)

For natural dentition, retention, stability, and supportFor natural dentition, retention, stability, and support

are derived through theare derived through the periodontiumperiodontium which provides;which provides; Sensory feedback mechanismSensory feedback mechanism

Difference in reaction of supporting structures toDifference in reaction of supporting structures to masticatorymasticatoryforcesforces

Differences in load transfer mechanism and physiologyDifferences in load transfer mechanism and physiology

2. Derivation of retention, stability and2. Derivation of retention, stability and

support forsupport for natural occlusionnatural occlusion


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2. Derivation of retention, stability and support for2. Derivation of retention, stability and support forcomplete denture occlusioncomplete denture occlusion

Complete dentures receive their retention, stability, and

support from the soft tissues overlying residual bone(ridges, buccal shelf, palate, etc.).

Denture Bearing Surface

RetentionRetention

Resistance to dislodgment forces in aResistance to dislodgment forces in a

vertical direction away from the bearingvertical direction away from the bearing

surfacesurface

Denture Bearing SurfaceDenture Bearing Surface

StabilityStability

Resistance to laterally oriented dislodgmentResistance to laterally oriented dislodgmentforcesforces

Denture Bearing SurfaceDenture Bearing Surface

SupportSupport Factors of the Bearing Surface which resistFactors of the Bearing Surface which resist

forces in a vertical direction towards theforces in a vertical direction towards the

bearing surfacebearing surface


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Natural occlusion

Physiologic levels of tension results inalveolar bone apposition (such as that

transmitted by loading the periodontalligament through natural dentition)

Complete denture occlusion

Non-physiologic compression as mayoccur under denture bases results in

further residual ridge resorption (RRR)

3. Reaction of supporting structures

Mobile bases on mucosaMobile bases on mucosa Teeth move as an unitTeeth move as an unit Malocclusion affects entireMalocclusion affects entire

base immediatelybase immediately NonNon--vertical forces affect allvertical forces affect all

teeth and are traumaticteeth and are traumatic

Incising affects all teethIncising affects all teethattached to baseattached to base

Bilateral balance is oftenBilateral balance is oftendesired for base stabilitydesired for base stability

Decreased tactile senseDecreased tactile sense

Retained in PDLRetained in PDL Units move independentlyUnits move independently Malocclusion effects notMalocclusion effects not

immediateimmediate NonNon--vertical forces affectvertical forces affect

only teeth involved andonly teeth involved andusually well toleratedusually well tolerated

Incising doesnIncising doesnt affectt affectposteriorsposteriors

Bilateral balance is rareBilateral balance is rare Tactile sensitivityTactile sensitivity

Natural DentitionNatural Dentition DentureDentureDentitionDentition

Summary

SummarySummary Goal of complete denture occlusion is preservationGoal of complete denture occlusion is preservation

of structure and restoration of function andof structure and restoration of function andestheticsesthetics

Consequences of tooth loss create anatomicConsequences of tooth loss create anatomicchanges which result in differences in derivation ofchanges which result in differences in derivation ofretention, stability and support between natural andretention, stability and support between natural andcomplete denture teethcomplete denture teeth

The differences in the design of natural andThe differences in the design of natural andcomplete denture occlusion are the consequence ofcomplete denture occlusion are the consequence ofdifferences in the derivation of retention, stabilitydifferences in the derivation of retention, stabilityand support.and support.

Complete denture form and tooth placement isComplete denture form and tooth placement isbiomechanical in naturebiomechanical in nature


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Types of Complete Denture OcclusionTypes of Complete Denture Occlusion

Bilateral balance

Neutrocentric

We prefer bilateral balanceWe prefer bilateral balancebecause this type of occlusalbecause this type of occlusal

arrangement limits tipping of the dentures duringarrangement limits tipping of the dentures during

parafunctionalparafunctional movements,movements,

Bilateral Balanced Denture OcclusionBilateral Balanced Denture Occlusion

The stable simultaneous contact ofThe stable simultaneous contact ofopposing upper and lower teeth inopposing upper and lower teeth in

centric relation position with a smoothcentric relation position with a smooth

bilateral gliding contact to any eccentricbilateral gliding contact to any eccentric

position within the normal range ofposition within the normal range of

mandibular function, developed tomandibular function, developed to

lessen or limit tipping or rotation of thelessen or limit tipping or rotation of thedenture bases in relation to thedenture bases in relation to the

supporting structures.supporting structures.

BalanceBalance during chewingduring chewing

BolusBolus

Bilateral Balanced Denture OcclusionBilateral Balanced Denture Occlusion

Traditionally bilateral balance wasachieved with anatomic posterior denture

teeth. (However, it can be achieved withnonanatomic teeth using balancing rampsor by manipulating the compensatingcurve.)


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Bilateral Balanced Denture Occlusion withBilateral Balanced Denture Occlusion with

Anatomic Posterior Denture TeethAnatomic Posterior Denture Teeth

Bilateral PosteriorCentric Contact

Centralized Forces Balanced Occlusion

to minimize tipping

ProtrusiveProtrusive BalancingBalancing WorkingWorking

CentricCentric

Monoplane with Balancing RampsMonoplane with Balancing Ramps

WorkingWorking BalancingBalancing

Bilateral balanced occlusion can also beBilateral balanced occlusion can also be

obtained withobtained with nonanatomicnonanatomic posterior teethposterior teethif balancing ramps are employed. In allif balancing ramps are employed. In alllateral excursions you should observe atlateral excursions you should observe at

least three points of contact bilaterally ifleast three points of contact bilaterally ifbilateral balance is to be achieved.bilateral balance is to be achieved.

ProtrusiveProtrusive

Monoplane OcclusionMonoplane Occlusion

((NeutrocentricNeutrocentric Concept)Concept)

This concept of occlusion assumes that the anterior-

posterior plane of occlusion should be parallel to the

denture foundation area and not dictated by condylarinclination.

The plane of occlusion is completely flat and level.

There is no curve of Wilson or Curve of Spee(compensating curve) incorporated into the set up.

There is no vertical overlap of the anterior teeth.

When using this concept of occlusion the patient isinstructed not to incise the bolus. With this tootharrangement the patient will become a chopper, not a

chewer or a grinder.

Monoplane OcclusionMonoplane Occlusion

((NeutrocentricNeutrocentric Concept)Concept)

CentricCentricBalancingBalancing

At balancing and protrusive positions there is separation ofAt balancing and protrusive positions there is separation of

the denture teeth in the posterior regions leading to tippingthe denture teeth in the posterior regions leading to tippingof the dentures. This may be disadvantageous in theof the dentures. This may be disadvantageous in the

patients exhibitingpatients exhibiting parafunctionalparafunctional grinding habitsgrinding habits


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HANAUHANAUS QUINTS QUINT

BALANCED OCCLUSIONBALANCED OCCLUSION

IMPORTANT NOTE:

ALL OF THE FOLLOWING SLIDES HAVE

ILLUSTRATIONS OF BALANCE IN THESAGITTAL PLANEANTEROPOSTERIORLY,

HOWEVER YOU MUST REMEMBER THATBALANCED OCCLUSION (AND HANAUS

QUINT) IS ALSO SEEN IN THE CORONALPLANE LATERALLY

(Hanaus Quint)

Hanau described fivefactors

that affect occlusal balance

Condylar Guidance (Inclination)

Incisal Guidance

Occlusal Plane Inclination

Cuspal Inclination Compensating Curve (Curves of Spee & Wilson)


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Theilman elaborated on the Hanaus Quintand described the inter-relationship ofthese five factors in order to maintain abalanced occlusion

CC==

CondylarCondylar InclinationInclination

OccPlaneOccPlane

xx IncisalIncisal GuidanceGuidance

xx CuspalCuspal InclinationInclination xx CompCurveCompCurve

C=Balanced OcclusionC=Balanced Occlusion

Theilmans Formula

HanauHanauss QuintQuint

Of these five factors, the patient presents you withCondylar Inclination determined anatomically (constant)

Occlusal Plane cannot be altered substantially sincefunctional requirements (Campers plane) dictate itsposition and orientation (relatively constant)

The remaining three factors can be controlled to some

degree by the dentist

Factors controlled by the dentistFactors controlled by the dentist

C=Condylar Inclination

OccPlane

x Incisal GuidanceIncisal Guidance

x CuspalCuspal InclinationInclinationx CompCurveCompCurve

HanauHanauss QuintQuint

Within the confines of esthetics and phonetics,minimize Incisal Guidance in Complete Denturesto minimize inclined tipping forces

Adjust remaining factors to maintain balance

C=Condylar Inclination

OccPlane

x Incisal GuidanceIncisal Guidance

x CuspalCuspal InclinationInclination x CompCurveCompCurve

CC==[[CondylarCondylarInclination]Inclination]

[[OccPlaneOccPlane]]




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When all five factors are in balance . . .

CC==CondylarCondylar InclinationInclination

OccPlaneOccPlane



. . . all teeth contact in excursive positions(excursive = lateral + protrusive movement)


OccPlaneOccPlane



If one of the factors changes it will affect balancedocclusion.

INCISAL GUIDANCEINCISAL GUIDANCE


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For example if the Incisal Guidance is increased theposterior teeth will disclude.

HANAUHANAUS QUINTS QUINT

For example if the Incisal Guidance is increased theposterior teeth will disclude.

The increased incisal guidance can be compensatedfor by increasing one or a combination of the otherfactors; Cuspal Inclination, CompCurve, (OccPlane) .


OccPlaneOccPlane



Increase the

inclination angleof the OccPlanePlane


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CUSP INCLINATIONCUSP INCLINATION A change in the Cusp Inclination will affect balancedocclusion. For example if zero degree (flat) cusp teeth areselected the posterior teeth will disclude.

A change in the Cusp Inclination will affect balanced

occlusion. For example if zero degree (flat) cusp teeth areselected the posterior teeth will disclude.

A change in the Cusp Inclination will affect balanced

occlusion. For example if zero degree (flat) cusp teeth areselected the posterior teeth will disclude.


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The minimized posterior disclusion can now also be

compensated for by increasing the OccPlane and/or

CompCurve

Summary of Laws of Articulation

Condylar inclination is the one factor that the dentist hasno control over since it is the property of the patient. This

factor is obtained by making protrusive and/or lateral jawregistrations from the patient.

CC== CondylarCondylarInclinationInclinationOccPlaneOccPlane




In general it is suggested that the IncisalGuidance for the complete denture patient

be minimized (within the confines ofesthetics and phonetics) to reducehorizontal forces of occlusion.


OccPlaneOccPlane




Occlusal Plane cannot be alteredsubstantially since functional

requirements dictate position


OccPlaneOccPlane




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The degree of Cuspal Inclination is dependent

on multiple factors (residual ridges,neuromuscular control, esthetics, etc.).However in general it is best to reduce cuspalinclination to help reduce horizontal forces ofocclusion.

CC== CondylarCondylar InclinationInclinationOccPlaneOccPlane




The Compensating Curve is very helpful

in obtaining balanced occlusion anddepending on the posterior tooth forms itcan easily be corrected to facilitateposterior tooth contacts in eccentricpositions.

CC== CondylarCondylar InclinationInclinationOccPlaneOccPlane



Working SideWorking Side

Centric OcclusionCentric Occlusion ProtrusiveProtrusive

Balancing SideBalancing Side

Bilateral Balanced Occlusion

Anatomic Tooth FormsAnatomic Tooth Forms


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Anatomic (30 degree)Anatomic (30 degree)balanced occlusionbalanced occlusion((Semi-anatomic)

MonoplaneMonoplane

neutrocentricneutrocentric oror

balanced with compensating curvesbalanced with compensating curves

or balancing ramps)or balancing ramps)LingualizedLingualized -- balancedbalanced

Posterior Tooth FormsPosterior Tooth Forms

Anatomic Tooth FormsAnatomic Tooth Forms

NonanatomicNonanatomic Tooth FormsTooth Forms SemiSemi--anatomic Tooth Formsanatomic Tooth Forms


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Goals of Complete Denture OcclusionGoals of Complete Denture Occlusion

Minimize trauma to thesupporting structures

Preserve remaining structures

Enhance stability

Esthetics, Speech andMastication

Enhance mastication

In addition we would like to decrease lateralIn addition we would like to decrease lateral

forces to the residual ridges.forces to the residual ridges.

General Concepts of Denture OcclusionGeneral Concepts of Denture Occlusion

Common Features

Functional anatomy is the main determinant ofdenture tooth position

Simultaneous, bilateral posterior contact in centricrelation (centric occlusion)

Centralization of centric occlusal forces over themandibular residual ridges

Buccal-Lingually

Anterior-Posteriorly

Balance and Monoplane OcclusionBalance and Monoplane Occlusion

Minimize vertical overlap within thedictates of esthetics and phonetics

Balance and Monoplane OcclusionBalance and Monoplane Occlusion

Minimize vertical overlap within thedictates of esthetics and phonetics


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Investigators have not shown one type ofdenture occlusion to be :

superior in functionsafer to oral structures

more acceptable to patients

Complete Denture OcclusionComplete Denture Occlusion Complete Denture OcclusionComplete Denture Occlusion

Neuromuscular control may be thesingle most significant factor in thesuccessful manipulation of complete

dentures under function

Tongue function anddenture wearingexperience

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Dent 343 Lect 9_handout