Setting Posterior Teeth

transcript

Setting Posterior TeethSetting Posterior Teeth

Set for FunctionSet for Function

Philosophies of Denture OcclusionPhilosophies of Denture Occlusion

Many philosophies of arranging denture occlusion

No definitive scientific studies prove one occlusal scheme clearly superior

Many philosophies of arranging denture occlusion

No definitive scientific studies prove one occlusal scheme clearly superior

Rationale for Dalhousie ApproachRationale for Dalhousie Approach

Principals to choose an occlusal scheme Based on clinical experience Dalhousie: two occlusal schemes :

• Lingualized Occlusion• Monoplane Occlusion

Principals to choose an occlusal scheme Based on clinical experience Dalhousie: two occlusal schemes :

• Lingualized Occlusion• Monoplane Occlusion

Occlusal SchemesAttempts to Stabilize DenturesOcclusal Schemes

Attempts to Stabilize Dentures

Lingualized Occlusion: Contacts on centered on mandibular ridge minimizes movement

Monoplane Occlusion: Lack of cusps minimizes lateral forces on denture

Lingualized Occlusion: Contacts on centered on mandibular ridge minimizes movement

Monoplane Occlusion: Lack of cusps minimizes lateral forces on denture

Based on the UCLA/IVOCLAR/ACP Series Based on the UCLA/IVOCLAR/ACP Series

Lingualized OcclusionLingualized OcclusionLingualized OcclusionLingualized Occlusion

Centric contacts are maxillary lingual cusp to central fossa / marginal ridge

Lingualized Occlusion

Anatomic teeth used in maxilla Better esthetics than

Monoplane Shallow cusped mandibular

teeth Forces centered over

mandibular ridge

Anatomic teeth used in maxilla Better esthetics than

Monoplane Shallow cusped mandibular

teeth Forces centered over

mandibular ridge

Lingualized OcclusionLingualized Occlusion

No overbite May or may not have balancing

contacts in excursions Anterior teeth - must make at

least grazing contacts in excursions

No overbite May or may not have balancing

contacts in excursions Anterior teeth - must make at

least grazing contacts in excursions

Lingualized OcclusionLingualized Occlusion

Maxillary anatomic (33°) Mandibular Teeth

Steep Condylar Guidance Shallow cusped (Anatoline)

Shallow Condylar Guidance Non-anatomic (Portrait 0°)

Maxillary anatomic (33°) Mandibular Teeth

Steep Condylar Guidance Shallow cusped (Anatoline)

Shallow Condylar Guidance Non-anatomic (Portrait 0°)

Denture Occlusion OptionsDenture Occlusion Options

AnatomicAnatomic

Semi-anatomicSemi-anatomic

Lingualized (lingual contact)

Non-anatomic (balancing ramp)Non-anatomic (balancing ramp)

Non-anatomicNon-anatomic

Set mandibular premolars & Set mandibular premolars & 11stst molar : molar :

• Level with occl plane Level with occl plane •Centered over ridge Centered over ridge

Set mandibular premolars & Set mandibular premolars & 11stst molar : molar :

• Level with occl plane Level with occl plane •Centered over ridge Centered over ridge

Occlusal planeOcclusal planeOcclusal planeOcclusal plane

Line indicating the crest of the ridgeLine indicating the crest of the ridgeLine indicating the crest of the ridgeLine indicating the crest of the ridge

Balanced Lingualized Occlusion

Maxillary anatomic opposing Mandibular shallow cusp

If using a lingualized posterior If using a lingualized posterior tooth form (Dentsply Anatoline) tooth form (Dentsply Anatoline)

• little or no Curve of Wilsonlittle or no Curve of Wilson• lingual and buccal cusps of lingual and buccal cusps of

level with plane of occlusion level with plane of occlusion

If using a lingualized posterior If using a lingualized posterior tooth form (Dentsply Anatoline) tooth form (Dentsply Anatoline)

• little or no Curve of Wilsonlittle or no Curve of Wilson• lingual and buccal cusps of lingual and buccal cusps of

level with plane of occlusion level with plane of occlusion

Second molar elevated by ~ 15Second molar elevated by ~ 15° from the occlusal ° from the occlusal planeplaneSecond molar elevated by ~ 15Second molar elevated by ~ 15° from the occlusal ° from the occlusal planeplane

15 degrees15 degrees15 degrees15 degrees

Max. lingual cusps Max. lingual cusps contact central contact central fossae/marginal ridgefossae/marginal ridge

~ 1mm space ~ 1mm space between buccal between buccal cuspscusps

Max. lingual cusps Max. lingual cusps contact central contact central fossae/marginal ridgefossae/marginal ridge

~ 1mm space ~ 1mm space between buccal between buccal cuspscusps

Maxillary lingual cusps firmly contact bilaterally simultaneously

Verify centric Verify centric No max. buccal cusp contacts in: No max. buccal cusp contacts in:

• • Centric Centric • • Lateral excursions Lateral excursions

Verify centric Verify centric No max. buccal cusp contacts in: No max. buccal cusp contacts in:

• • Centric Centric • • Lateral excursions Lateral excursions

Centric PositionCentric PositionCentric PositionCentric Position

Verify excursive contactsVerify excursive contacts

Anterior teeth are in contact Anterior teeth are in contact during lateral excursions during lateral excursions

Verify excursive contactsVerify excursive contacts

Anterior teeth are in contact Anterior teeth are in contact during lateral excursions during lateral excursions

Working ExcursionsWorking ExcursionsWorking ExcursionsWorking Excursions

Note the Note the balancing contactsbalancing contactsNote the Note the balancing contactsbalancing contacts

Balancing ExcursionsBalancing Excursions

Effect of Mandible Moving Downward During Excursions

QuickTime™ and aMotion JPEG OpenDML decompressor

are needed to see this picture.

Maintaining Balancing Contacts

Change occlusal plane angle Increase compensating curves Increase cusp angles

Achieving BalanceAchieving Balance

• Condylar angulation Recorded with protrusive record

• Cusp angle Selected by dentist

• Condylar angulation Recorded with protrusive record

• Cusp angle Selected by dentist

Achieving BalanceAchieving Balance

• Occlusal Plane Determined by dentist with wax rims

• Curve of Spee & Curve of Wilson Controlled by inclination of teeth

• Occlusal Plane Determined by dentist with wax rims

• Curve of Spee & Curve of Wilson Controlled by inclination of teeth

Checking for BalanceChecking for Balance

Feels Feels SmooSmoooooooooothth in in excursions excursions

- Fingers on Maxillary Canines- Fingers on Maxillary Canines- On Articulator- On Articulator

Feels Feels SmooSmoooooooooothth in in excursions excursions

- Fingers on Maxillary Canines- Fingers on Maxillary Canines- On Articulator- On Articulator

Assessing BalanceAssessing Balance

• Jumps or bumps are due to cusp tips moving over other cusp tips, inclines, marginal ridges

Occlusal RefinementOcclusal Adjustment, Selective Grinding

Set teeth as close to: Maximum intercuspation Balance

All setups will need some adjustment

Set teeth as close to: Maximum intercuspation Balance

All setups will need some adjustment

‘IIF’ Rule‘IIF’ Rule

Inner Inclines (inside of cusp)Outer Inclines(outside of cusp)

WorkingContacts

Inner Inclines (inside of cusp)Outer Inclines(outside of cusp)

WorkingContactsIIF you have contacts on the Inner Inclines of Functional cusps they are balancing contactsIIF you have contacts on the Inner Inclines of Functional cusps they are balancing contacts

Find the Balancing Contact

What type of Contact?What type of Contact?

What type of Contacts?What type of Contacts?

What type of Contact?What type of Contact?

Assess ContactsAssess Contacts Centric Stops Excursions

Centric Stops Excursions

Non-Balanced Lingualized Occlusion

Maxillary anatomic opposing mandibular non-anatomic

Mortar & pestle occlusion without maxillary Mortar & pestle occlusion without maxillary buccal cusp contactbuccal cusp contact

Lack of mandibular cusp angles and no Lack of mandibular cusp angles and no attempt to balance the occlusionattempt to balance the occlusion

No compensating curvesNo compensating curvesNo overbiteNo overbite

No overbiteNo overbite

Magnitude of OverjetMagnitude of OverjetMagnitude of OverjetMagnitude of Overjet

More for Class II More for Class II patients patients

Class IClass I Class IIClass II

Magnitude of Horizontal OverlapMagnitude of Horizontal Overlap

Class III patients

Little or no overjet

Class III patients

Little or no overjet

Class IIIClass III

Setting the posterior teethSetting the posterior teeth • Teeth should end prior to the ascending Teeth should end prior to the ascending

ramus ramus

Setting the posterior teethSetting the posterior teeth • Teeth should end prior to the ascending Teeth should end prior to the ascending

ramus ramus

• Maxillary lingual cusps contact central groove/marginal ridge of the opposing teeth

The horizontal overlap

should be ideal and

should be sufficient to

prevent biting of the cheek

and corner of the mouth

The horizontal overlap

should be ideal and

should be sufficient to

prevent biting of the cheek

and corner of the mouth Horizontal Horizontal

overlapoverlapHorizontal Horizontal

overlapoverlap

• All maxillary teeth, with the exception of the lateral incisors and cuspids, should be on the plane of

occlusion

• All maxillary teeth, with the exception of the lateral incisors and cuspids, should be on the plane of

occlusion

Monoplane OcclusionMonoplane Occlusion

Cuspless teeth (0°) on a flat plane with 1.5-2.0 mm overjet

No cusp to fossa relationship No anterior contacts in

centric position

Cuspless teeth (0°) on a flat plane with 1.5-2.0 mm overjet

No cusp to fossa relationship No anterior contacts in

centric position

Eliminate cusps lateral forces reduced improves stability

Simplifies tooth arrangement

Eliminate cusps lateral forces reduced improves stability

Simplifies tooth arrangement

No overbite (would cause tilting)

Overjet of 2 mm is used to create an illusion of overbite

No overbite (would cause tilting)

Overjet of 2 mm is used to create an illusion of overbite

Excursions - may or may not contact on balancing sides

Depends on condylar inclination and other aspects of the tooth arrangement

Excursions - may or may not contact on balancing sides

Depends on condylar inclination and other aspects of the tooth arrangement

Anterior teeth make contact in excursions

Modifications have been proposed to minimize the tilting potential: Balancing ramps Compensating curves

Anterior teeth make contact in excursions

Modifications have been proposed to minimize the tilting potential: Balancing ramps Compensating curves

Monoplane Occlusionwithout condylar influence

Monoplane OcclusionMonoplane OcclusionAdvantages• Technically easier to achieve• Use when:

– Difficulty obtaining repeatable centric records (muscle incoordination)

– Skeletal malocclusion (Class II, III)– Severe residual ridge resorption

– Reduces horizontal forces

Advantages• Technically easier to achieve• Use when:

– Difficulty obtaining repeatable centric records (muscle incoordination)

– Skeletal malocclusion (Class II, III)– Severe residual ridge resorption

– Reduces horizontal forces

Monoplane Occlusion

Disadvantages• Poorer appearance• Can be unstable if condylar

guidance is steep (posterior teeth separate, leaving only the anteriors in contact)

Disadvantages• Poorer appearance• Can be unstable if condylar

guidance is steep (posterior teeth separate, leaving only the anteriors in contact)

Monoplane Occlusion

Clinical remount on an articulator Practice doing a clinical remount

Adjusting Monoplane Occlusion

Main adjustment is flat If heavy prematurity near

fossa, slightly shallow fossa

Main adjustment is flat If heavy prematurity near

fossa, slightly shallow fossa

Setting Posterior Teeth

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