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Setting Posterior Teeth. Set for Function. Philosophies of Denture Occlusion. Many philosophies of arranging denture occlusion No definitive scientific studies prove one occlusal scheme clearly superior. Rationale for Dalhousie Approach. Principals to choose an occlusal scheme
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Setting Posterior Teeth Set for Function
Philosophies of Denture Occlusion • Many philosophies of arranging denture occlusion • Nodefinitivescientific studies prove one occlusal scheme clearly superior
Rationale for Dalhousie Approach • Principals to choose an occlusal scheme • Based on clinical experience • Dalhousie: two occlusal schemes : • Lingualized Occlusion • Monoplane Occlusion
Occlusal SchemesAttempts 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 • Centric contacts are maxillary lingual cusp to central fossa / marginal ridge Based on the UCLA/IVOCLAR/ACP Series
Lingualized Occlusion • Anatomic teeth used in maxilla • Better esthetics than Monoplane • Shallow cusped mandibular teeth • Forces centered over mandibular ridge
Lingualized Occlusion • No overbite • May or may not have balancing contacts in excursions • Anterior teeth - must make at least grazing contacts in excursions
Lingualized Occlusion • Maxillary anatomic (33°) • Mandibular Teeth • Steep Condylar Guidance • Shallow cusped (Anatoline) • Shallow Condylar Guidance • Non-anatomic (Portrait 0°)
Semi-anatomic Denture Occlusion Options Non-anatomic (balancing ramp) Lingualized (lingual contact) Non-anatomic Anatomic
Occlusal plane • Set mandibular premolars & 1st molar : • Level with occl plane • Centered over ridge Line indicating the crest of the ridge
Balanced Lingualized Occlusion Maxillary anatomic opposing Mandibular shallow cusp
If using a lingualized posterior tooth form (Dentsply Anatoline) • little or no Curve of Wilson • lingual and buccal cusps of level with plane of occlusion
15 degrees Second molar elevated by ~ 15° from the occlusal plane
Max. lingual cusps contact central fossae/marginal ridge ~ 1mm space between buccal cusps
Maxillary lingual cusps firmly contact bilaterally simultaneously
Centric Position Verify centric No max. buccal cusp contacts in: • Centric • Lateral excursions
Working Excursions Verify excursive contacts Anterior teeth are in contact during lateral excursions
Balancing Excursions Note the balancing contacts
Maintaining Balancing Contacts • Change occlusal plane angle • Increase compensating curves • Increase cusp angles
Achieving Balance • Condylar angulation • Recorded with protrusive record • Cusp angle • Selected by dentist
Achieving Balance • Occlusal Plane • Determined by dentist with wax rims • Curve of Spee & Curve of Wilson • Controlled by inclination of teeth
Checking for Balance Feels Smoooooothin excursions - Fingers on Maxillary Canines - On Articulator
Assessing 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
‘IIF’ Rule IIF you have contacts on the Inner Inclines of Functional cusps they are balancing contacts
Assess Contacts • Centric Stops • Excursions
Non-Balanced Lingualized Occlusion Maxillary anatomic opposing mandibular non-anatomic
Mortar & pestle occlusion without maxillary buccal cusp contact
Lack of mandibular cusp angles and no attempt to balance the occlusion
No compensating curves No overbite
More for Class II patients Magnitude of Overjet Class I Class II
Class III Magnitude of Horizontal Overlap Class III patients Little or no overjet
Setting the posterior teeth • Teeth should end prior to the ascending 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 Horizontal overlap
All maxillary teeth, with the exception of the lateral incisors and cuspids, should be on the plane of occlusion
Monoplane 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
Monoplane Occlusion • Eliminate cusps • lateral forces reduced • improves stability • Simplifies tooth arrangement
Monoplane Occlusion • No overbite (would cause tilting) • Overjet of 2 mm is used to create an illusion of overbite