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Denture Tooth Forms and Occlusal Forms (PowerPoint)

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Denture Tooth Forms and Occlusal Forms (PowerPoint) Powered By Docstoc
					   Philosophies of
Occlusion for Implants
Implant Occlusion
 Single Crown
 Fixed Partial Dentures
 Full arch prostheses (screw retained)
 Overdentures
Many Philosophies of Occlusion


No definitive scientific studies to prove:
   one type of tooth form

   one type of occlusal scheme

   to be clearly preferred by patients

   to be more efficient than another
Tooth Forms        Occlusal Schemes

   Anatomic          Canine Guidance
   Non Anatomic       (Mutually Protected)
                      Group Function
                      Lingualized
                       (Balanced)
                      Monoplane
Denture Tooth Forms and
Occlusal Forms



               QuickTime™ and a
           TIFF (LZW) decompressor
        are neede d to see this picture.
Occlusion & Implants
   Evidence Based Review
    Taylor, Wiens et al. J Prosthet Dent 2005;94:555-560


   No Preferred occlusal scheme
   Clinicians advocate axial loading of implants,
    but no evidence, at present,
    demonstrating benefits
Occlusion & Implants
   Evidence Based Review
    Taylor, Wiens et al. J Prosthet Dent 2005;94:555-560


   No evidence at present that
     progressive occlusal loading of implant
      is beneficial
     occlusal overload is detrimental to
      implants
Absence of Scientific Evidence
         Not proof against!

    Follow best available clinical
              principles
   Do not build in heavy non-axial
       loading or overloading
Clinical Principles for Occlusion

     Based on Clinical Experience
       Not Scientific Evidence
      General Principles

Improve denture stability or axial
  loading of single teeth
   Centric contacts on flat surfaces,
    not inclines
General Principles
                          Center over
                          lower ridge

 Posterior
 Overjet to
               1-2 mm
 Avoid Cheek                            1-2 mm
 Biting
                    Anatomic setup         Nonanatomic
                                              setup
General Principles

 Improve denture
   stability or single
   tooth loading
    Center occlusal contacts
     over ridge
    Simultaneous posterior
     contacts in centric
        General Occlusal Principles

For overdentures or full arch
  prostheses opposing a CD:
 No anterior contacts in centric
       Minimizes anterior resorption
   Grazing anterior contacts in
    excursions
       Incising
Occlusal Schemes

         Canine Guidance   Single Teeth
         Group Function      FPD’s
         Lingualized
         Monoplane         Dentures
Crowns or FPD’s
 Either canine guidance or group function
  works - no preference
 Use what the patient has
 Use what would be easiest
       Overdentures
             or
    Full Arch Prostheses

ALL Occlusal Schemes Devised to
  Maximize Denture Stability
Lingualized Occlusion

   Maxillary cusped tooth
   Mandibular cuspless or shallow cusped
    tooth
   Maxillary lingual cusp balances
    like a mortar in a pestle
Lingualized Occlusion


                        • Lingual cusp contacts
                          opposing central fossae

                        • Mandibular cuspal inclines
                          are shallow (0°, 10°)

                        • Less lateral displacement
Lingualized Occlusion
How Stability is Improved
   Simultaneous bilateral
    anterior and posterior in
    all excursions

   Tilting forces theoretically
    neutralized
     Enter Bolus Exit Balance?
   Many patients chew bilaterally
   Biting forces maximum close to intercuspation
    (where balance most effective)
   Non-functional aspects (swallow)
        Point of Loading Affects Stability
   Browning, 1986

       Loaded centrally, M, D, L, B
                                               M
       B caused unseating
                                       B
                                           C
       Central loading better than            L
        distal loading
                                       D
Lingualized Contacts



                       Working Side

   Only buccal cusp
    contact is inner
    incline of
    mandibular teeth
    (balancing)
                       Balancing Side
‘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)
Test!
    Rules for Balancing Contacts
 Balancing contacts should be lines, not
  points
 Balancing contacts should never be heavier
  than working contacts
Balanced Occlusion (Lingualized)
     Indirect evidence that balanced occlusion may:
        reduce ridge resorption (Maeda & Wood , 1989)

        allow for increased functional forces in
         excursions (Miralles et al, 1989)
    Lingualized Cusp Angles

   Always use steep cusped
    maxillary tooth (33°)
   When condylar guidance is
    steeper use more cusp angle
    in mandible (10°)
    Lingualized Occlusion
   Balance cannot be set without an articulator
   Clinical remount on an articulator - fewer
    adjustments
Condylar Inclination
   Posterior teeth separate as working
    condyle moves forward (and
    downward)
   Anterior teeth contact
   Closer to condyle, more separation
   More anterior separation of
    Premolars if steep anterior guidance
Effect of Mandible Moving Downward
During Excursions
Maintaining Balancing Contacts
       Change occlusal plane angle
       Increase compensating curves
       Increase cusp angles or effective cusp
        angles
       Checking for Balance

Feels Smooooooth in excursions
    - Fingers on max. canines
    - Check on articulator
Assess
Contacts:
 Centric Stops
 Excursions
Improving Denture Occlusion

      Most important cusp - maxillary lingual
      Mandibular buccal cusps more lateral - more
       tipping
When Not to Balance
     Difficulty in obtaining repeatable centric
      record
       incoordination,
       muscle splinting
     Dramatic malocclusions
     Severe ridge resorption
        lateral forces displace the denture

        Implants tend to negate this factor
Monoplane Occlusion
 Cuspless teeth set on a flat plane with 1.5- 2
  mm overjet
 No cusp to fossa relationship
 No anterior contacts present in centric
  position
 No overbite
    Monoplane Occlusion
    How Stability is Improved

   Elimination of cusps
        Lateral forces reduced, improving stability
        Simplifies denture tooth arrangement
Monoplane Occlusion
With Condylar Inclination
Monoplane Occlusion
With Condylar Inclination
Ensure Teeth Set Over Ridge
 Minimize tilting/tipping
 Maximize stability
 Minimize contacts on buccal of flat cusps
             Monoplane Occlusion
   Functional, but unesthetic
   Not balanced - flat
   Zero degree teeth can be
    balanced if condylar
    inclinations are shallow
Monoplane Occlussion - When?

   Jaw size discrepancies, malocclusions
     cross-bite, Cl II, III
   Minimal ridge
     reduces horizontal forces

     implants help

   Uncoordinated jaw movements
               Summary
   No definitive studies to show one type
    of occlusion is best
   Follow established clinical principles
   Assess each case - adapt to clinical
    situation
   Continue to read the literature

				
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