Concepts of Occlusion Concepts of Occlusion Vicki C Petropoulos DMD, MS Vicki C Petropoulos DMD, MS Associate Professor of Preventive and Restorative Associate Professor of Preventive and Restorative Sciences Sciences University of Pennsylvania University of Pennsylvania School of Dental Medicine School of Dental Medicine
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Concepts of Occlusion Concepts of Occlusion
Vicki C Petropoulos DMD, MSVicki C Petropoulos DMD, MS
Associate Professor of Preventive and Restorative Associate Professor of Preventive and Restorative SciencesSciences
University of PennsylvaniaUniversity of Pennsylvania
School of Dental MedicineSchool of Dental Medicine
AcknowlegementsAcknowlegements
��Many of these images are courtesy of theMany of these images are courtesy of the
American College of American College of ProsthodontistsProsthodontists, UCLA , UCLA
�� To understand differences between To understand differences between natural dentition and complete denture natural dentition and complete denture occlusionocclusion
�� To understand the goals of complete To understand the goals of complete denture occlusion and why balance is denture occlusion and why balance is neededneeded
�� To understand the four types of denture To understand the four types of denture occlusionocclusion
�� To understand HanauTo understand Hanau’’s s QuintQuint
Learning GoalsLearning Goals
�� To understand the different types of To understand the different types of
posterior tooth forms, adv. and posterior tooth forms, adv. and disadvdisadv..
Natural dentitionNatural dentition presents presents in a variety of individual in a variety of individual tooth size, shape, form and tooth size, shape, form and alignment, but ideally exhibit alignment, but ideally exhibit certain characteristic certain characteristic occlusion features.occlusion features.
•• Mutually Protective Mutually Protective Scheme of OcclusionScheme of Occlusion
Natural Occlusion
(organic)
Complete denture Complete denture ““dentitiondentition”” also presents in also presents in a variety of forms, but also a variety of forms, but also exhibit certain common exhibit certain common characteristicscharacteristics
�� Difference in reaction of supporting structures to Difference in reaction of supporting structures to masticatorymasticatory forcesforces
�� Differences in load transfer mechanism and physiologyDifferences in load transfer mechanism and physiology
2. Derivation of retention, stability and 2. Derivation of retention, stability and
support for support for natural occlusionnatural occlusion
2. Derivation of retention, stability and support for 2. Derivation of retention, stability and support for complete complete denture occlusiondenture 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 a vertical Resistance to dislodgment forces in a vertical
direction away from the bearing surfacedirection away from the bearing surface
Denture Bearing SurfaceDenture Bearing Surface
•• StabilityStability
�� Resistance to laterally oriented dislodgment forcesResistance to laterally oriented dislodgment forces
Denture Bearing SurfaceDenture Bearing Surface
•• SupportSupport�� Factors of the Bearing Surface which resist forces Factors of the Bearing Surface which resist forces
in a vertical direction towards the bearing surfacein a vertical direction towards the bearing surface
Natural occlusion
Physiologic levels of tension results in
alveolar bone apposition (such as that
transmitted by loading the periodontal
ligament through natural dentition)
Complete denture occlusion
Non-physiologic compression as may
occur 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 entire base Malocclusion affects entire base immediatelyimmediately
•• NonNon--vertical forces affect all vertical forces affect all teeth and are traumaticteeth and are traumatic
•• Incising affects all teeth attached Incising affects all teeth attached to baseto base
•• Bilateral balance is often desired Bilateral balance is often desired for base stabilityfor base stability
•• Decreased tactile senseDecreased tactile sense
•• Retained in PDLRetained in PDL
•• Units move independentlyUnits move independently
•• Malocclusion effects not Malocclusion effects not immediateimmediate
•• NonNon--vertical forces affect only vertical forces affect only teeth involved and usually teeth involved and usually well toleratedwell tolerated
•• Incising doesnIncising doesn’’t affect t affect posteriorsposteriors
•• Bilateral balance is rareBilateral balance is rare
SummarySummary•• Goal of complete denture occlusion is preservation of Goal of complete denture occlusion is preservation of
structure and restoration of function and estheticsstructure and restoration of function and esthetics
•• Consequences of tooth loss create anatomic changes Consequences of tooth loss create anatomic changes which result in differences in derivation of retention, which result in differences in derivation of retention, stability and support between natural and complete denture stability and support between natural and complete denture teethteeth
•• The differences in the design of natural and complete The differences in the design of natural and complete denture occlusion are the consequence of differences in denture occlusion are the consequence of differences in the derivation of retention, stability and support.the derivation of retention, stability and support.
•• Complete denture form and tooth placement is Complete denture form and tooth placement is biomechanical in naturebiomechanical in nature
��We spend 2We spend 2--4 hours/day in parafunction 4 hours/day in parafunction
and only 10 minutes/day in functionand only 10 minutes/day in function
Objective of Balanced Objective of Balanced
OcclusionOcclusion�� To create stability of the denture bases To create stability of the denture bases during eccentric movementduring eccentric movement
�� Instability of the bases leads to:Instability of the bases leads to:
�� Irritation of the hard and soft tissuesIrritation of the hard and soft tissues
�� Excessive denture movementExcessive denture movement
�� Unequal distribution of forcesUnequal distribution of forces
�� Potential for more rapid loss of osseous Potential for more rapid loss of osseous supportsupport
When do we Achieve Balanced When do we Achieve Balanced
Occlusion?Occlusion?
�� At the final try in, we will verify the Jaw At the final try in, we will verify the Jaw
Relationship RecordRelationship Record
�� At that point we will do a protrusive record At that point we will do a protrusive record
to set the condylar inclinationto set the condylar inclination
�� Balance will be achieved in the labBalance will be achieved in the lab
Types of Denture TeethTypes of Denture Teeth
�� Artificial teeth can beArtificial teeth can be
�� Anatomic (30 degrees or greater)Anatomic (30 degrees or greater)
�� SemiSemi--anatomic (30 to 0 degrees)anatomic (30 to 0 degrees)
�� Nonanatomic (0 degrees)Nonanatomic (0 degrees)
AdvantagesAdvantages
�� AnatomicAnatomic
�� More estheticMore esthetic
�� Supposed higher Supposed higher
chewing efficiencychewing efficiency
�� Ease in achieving Ease in achieving
balanced occlusionbalanced occlusion
�� NonanatomicNonanatomic
�� Easier to setEasier to set
�� Kinder to edentulous Kinder to edentulous
ridgesridges
DisadvantagesDisadvantages
�� AnatomicAnatomic
�� More time consuming More time consuming
to setto set
�� May cause more/faster May cause more/faster
bone resorptionbone resorption
�� NonanatomicNonanatomic
�� UnaestheticUnaesthetic
�� Supposed to decrease Supposed to decrease
chewing efficiencychewing efficiency
BalanceBalance
�� Balance can be achieved with anatomic Balance can be achieved with anatomic
OR monoplane teeth.OR monoplane teeth.
��With anatomic teeth it is generated by the With anatomic teeth it is generated by the
tooth arrangementtooth arrangement
��With monoplane teeth it is generated by a With monoplane teeth it is generated by a
balancing rampbalancing ramp
Verify contacts in working excursionsVerify contacts in working excursions
Lack of working side contacts may be the result of:Lack of working side contacts may be the result of:•• Poor buccal centricPoor buccal centric
•• Insufficient curve of WilsonInsufficient curve of Wilson
•• Working interferences in the 2Working interferences in the 2ndnd molar regionmolar region
•• Balancing interferences on the opposite sideBalancing interferences on the opposite side
**Check these in the Check these in the order citedorder cited..
Verify contacts during balancing excursionVerify contacts during balancing excursion
Lack of balancing side contacts may be the result of:Lack of balancing side contacts may be the result of:•• Poor lingual centricPoor lingual centric
•• Working interferences on the opposite side, particularly in the Working interferences on the opposite side, particularly in the
22ndnd molar regionmolar region
BalancingBalancing ProtrusiveProtrusive
WorkingWorking
�� All things being considered, the most All things being considered, the most
successful denture wearers are usually successful denture wearers are usually
those who have a good patient/provider those who have a good patient/provider
relationship and a good, positive outlook relationship and a good, positive outlook
and good and good neuroneuro--musculature control.musculature control.
Always RememberAlways Remember……
Dentures are not a replacement for teethDentures are not a replacement for teeth……
Dentures are a replacement for no teeth.Dentures are a replacement for no teeth.
OcclusionOcclusion
�� The static relationship between the The static relationship between the
incising or masticating surfaces of the incising or masticating surfaces of the
maxillary and mandibular teeth or tooth maxillary and mandibular teeth or tooth
�� Any movement of the mandible from the Any movement of the mandible from the centric occlusion position that results in centric occlusion position that results in tooth contact is termed tooth contact is termed eccentriceccentric..
�� There are three basic eccentric There are three basic eccentric movementsmovements
�� ProtrusiveProtrusive
�� LaterotrusiveLaterotrusive
�� RetrusiveRetrusive
ProtrusiveProtrusive
�� The mandible moves forward from the The mandible moves forward from the
centric occlusion positioncentric occlusion position
�� The predominant protrusive contact occurs The predominant protrusive contact occurs
between the maxillary and mandibular between the maxillary and mandibular
anterior teeth.anterior teeth.
ProtrusiveProtrusive
Laterotrusive (Working)Laterotrusive (Working)
��Most function occurs on the working side Most function occurs on the working side (lateral movement) the side to which the (lateral movement) the side to which the mandible is shifted.mandible is shifted.
��Working contacts and crossWorking contacts and cross--tooth contacts tooth contacts occur on the working side.occur on the working side.
��Working contacts occur between the inner Working contacts occur between the inner inclines of max buccal and outer inclines inclines of max buccal and outer inclines of mand buccal.of mand buccal.
�� Earlier rehabs were modified by eliminating Earlier rehabs were modified by eliminating
balancing contactsbalancing contacts
�� Led to the functionally generated path or Led to the functionally generated path or ““wax wax
chewchew--inin”” techniquetechnique
�� Importance of incisal guidance discovered Importance of incisal guidance discovered
and incorporated into the occlusal schemeand incorporated into the occlusal scheme
�� Results in tipping forces on a dentureResults in tipping forces on a denture
Group FunctionGroup Function
�� Based on the philosophy that the more Based on the philosophy that the more
teeth to share the load the betterteeth to share the load the better
�� Incisal guidance established firstIncisal guidance established first
�� Spreads working side contact over 3 or more Spreads working side contact over 3 or more
teeth in each archteeth in each arch
�� These teeth should be adjacent to each otherThese teeth should be adjacent to each other
�� Involves buccal cusps onlyInvolves buccal cusps only
Group FunctionGroup Function
Centric RelationCentric Relation
�� The maxillomandibular relationship in The maxillomandibular relationship in which the condyles articulate with the which the condyles articulate with the thinnest avascular portion of their thinnest avascular portion of their respective disks with the complex in the respective disks with the complex in the anterior superior position against the anterior superior position against the shapes of the articular eminence. shapes of the articular eminence.
�� This position is independent of tooth This position is independent of tooth contactcontact
Centric RelationCentric Relation
�� The most important factor to remember is The most important factor to remember is
Monoplane with Balancing RampsMonoplane with Balancing Ramps
WorkingWorking BalancingBalancing
Bilateral balanced occlusion can also be Bilateral balanced occlusion can also be
obtained with obtained with nonanatomicnonanatomic posterior teeth posterior teeth
if balancing ramps are employed. In all if balancing ramps are employed. In all
lateral excursions you should observe at lateral excursions you should observe at
least three points of contact bilaterally if least three points of contact bilaterally if
bilateral balance is to be achieved. bilateral balance is to be achieved.
ProtrusiveProtrusive
Lingualized Opposing Monoplane with Lingualized Opposing Monoplane with
Balancing RampsBalancing Ramps
�� A similar concept is used when A similar concept is used when lingualizedlingualized maxillary maxillary teeth oppose teeth oppose nonanatomicnonanatomic teeth in the mandible. In teeth in the mandible. In all lateral excursions you should observe at least all lateral excursions you should observe at least three points of contact bilaterally to maintain bilateral three points of contact bilaterally to maintain bilateral balance. balance.
WorkingWorking BalancingBalancing
Monoplane Occlusion Monoplane Occlusion
((NeutrocentricNeutrocentric Concept)Concept)
This concept of occlusion assumes that the anteriorThis concept of occlusion assumes that the anterior--posterior plane posterior plane
of occlusion should be parallel to the denture foundation area aof occlusion should be parallel to the denture foundation area and nd
not dictated by condylar inclination.not dictated by condylar inclination.
The plane of occlusion is completely flat and level. There is nThe plane of occlusion is completely flat and level. There is no o
curve of Wilson or Curve of Spee (compensating curve) curve of Wilson or Curve of Spee (compensating curve)
incorporated into the set up.incorporated into the set up.
There is no vertical overlap of the anterior teeth.There is no vertical overlap of the anterior teeth.
When using this concept of occlusion the patient is instructed nWhen using this concept of occlusion the patient is instructed not to ot to
incise the bolus. With this tooth arrangement incise the bolus. With this tooth arrangement DeVanDeVan noted that noted that
““the patient will become a chopper, not a chewer or a grinder.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 of At balancing and protrusive positions there is separation of
the denture teeth in the posterior regions leading to tipping the denture teeth in the posterior regions leading to tipping
of the dentures. This may be disadvantageous in the of the dentures. This may be disadvantageous in the
SemiSemi--anatomic Tooth Formsanatomic Tooth Forms
NonanatomicNonanatomic Tooth FormsTooth Forms
General Concepts of Denture OcclusionGeneral Concepts of Denture Occlusion
�� Common FeaturesCommon Features
�� Functional anatomy is the main determinant of denture Functional anatomy is the main determinant of denture tooth positiontooth position
�� Simultaneous, bilateral posterior contact in centric relation Simultaneous, bilateral posterior contact in centric relation (centric occlusion)(centric occlusion)
�� Centralization of centric occlusal forces over the Centralization of centric occlusal forces over the mandibular residual ridgesmandibular residual ridges
•• BuccalBuccal--LinguallyLingually
•• AnteriorAnterior--PosteriorlyPosteriorly
Balance and the Monoplane OcclusionBalance and the Monoplane Occlusion
Minimize vertical overlap within the
dictates of esthetics and phonetics
Balance and Monoplane OcclusionBalance and Monoplane Occlusion