Transcript Setting Posterior Teeth

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
 Principles to choose an occlusal scheme
 Based on clinical experience
 Dalhousie: two occlusal schemes :
• Lingualized Occlusion
• Monoplane Occlusion
Occlusal 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 Occlusal Scheme
 Centric contacts:
 Maxillary lingual cusp to
central fossa / marginal
ridge
Based on the UCLA/IVOCLAR/ACP Series
Appearance
 Anatomic teeth used in maxilla
 Better esthetics than Monoplane
 Shallow cusped mandibular teeth
 Forces centered over mandibular
ridge
Lingualized Occlusion
 No anterior vertical overlap (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
 If Steep Condylar Guidance
 Shallow cusped (Anatoline)
 If Shallow Condylar Guidance
 Non-anatomic (Portrait 0°)
Denture Occlusion Options
Semi-anatomic
Non-anatomic
(balancing ramp)
Lingualized
(lingual contact)
Anatomic
Nonanatomic
Occlusal plane
Set mandibular premolars &
1st molar :
• Level with occl plane
• Centered over ridge
Line indicating the crest of the ridge
Balanced
Lingualized Occlusion
 In centric - simultaneous bilateral posterior
contacts (maxillary lingual cusp)
 In excursions - bilateral contacts of posterior
(max. ling.cusp) & anterior teeth so denture
does not displace/tip
Mandibular Tooth Form
 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 excursions
Balancing Excursions
Note the balancing contacts
Effect of Mandible Moving
Downward During Excursions
Effect of Condylar
Guidance
As angle gets steeper, more
separation of posterior teeth in
excursions
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 Smooooooth in 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 Refinement
Occlusal 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
B
L
B
Working
Contacts
L
Inner Inclines (inside of cusp)
Outer Inclines(outside of cusp)
Rules for Balancing
Contacts
 Balancing contacts should be
lines, not points
 Balancing contacts should
never be heavier than working
Find the Balancing
Contact
Find the Balancing
Contact
What type of Contact?
What type of Contact?
What type of Contacts?
What type of Contact?
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
No overbite
Magnitude of Horizontal Overlap (Overjet)
Class I
More for Class II
patients
Class II
Magnitude of Horizontal Overlap
Class III
Class III patients
Little or no overjet
A-P Length of Posterior Teeth
• Teeth should end prior to ascending
portion of ramus
• Maxillary lingual
cusps contact central
groove/marginal ridge
of the opposing teeth
The horizontal
overlap
prevents biting
of cheek & lips
Horizontal
overlap
• All maxillary teeth, with exception of lateral incisors
and cuspids, should be on the plane of occlusion
Monoplane Occlusion
Monoplane Scheme
 Cuspless teeth (0°) on flat plane
 1.5-2 mm overjet
 No cusp to fossa relationship
 No anterior contacts in centric position
Monoplane Philosophy
 Eliminate cusps
 lateral forces reduced
 improves stability
 Simplifies tooth arrangement
Monoplane Anterior Setup
 No overbite (would cause
tilting)
 Overjet of 2 mm is used to
create an illusion of
overbite
Monoplane Excursive Contacts
 Excursions - may or may not
contact on balancing sides
 Depends on condylar inclination
& other aspects of tooth
arrangement
Maintaining Stability
 Anterior teeth make contact
in excursions
 Modifications have been
proposed to minimize the
tilting potential:
 Balancing ramps
 Compensating curves
Monoplane Excursive Contacts
without condylar influence
Monoplane Occlusion
As mandible moves laterally
(L) or protrusively (P)
condyle(s) translate forward
separating teeth on one (L)
or both sides (P)
Monoplane Advantages
• Technically easier to set
• Minimizes lateral forces
• Use when:
– Difficulty obtaining repeatable centric
records (muscle incoordination)
– Skeletal malocclusion (Class II, III)
– Severe residual ridge resorption
Monoplane
Disadvantages
• Poorer appearance
• Can be unstable if condylar
guidance is steep (posterior
teeth separate, leaving only the
anteriors in contact)
Monoplane Occlusion
 Always take a protrusive record
prior to setting teeth – need to know
protrusive angle to select teeth
 At delivery, 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
Videos
 Setting Mandibular Posterior Teeth
 Setting Maxillary Posterior Teeth
 View outside of Class:
 Principles for Centric Contacts Lingualized Occlusion