6. Jaw records Flashcards
What are the 3 components of jaw records
- facebow
- vertical (VDO)
- Horizontal (MIP or CR)
During RPD treatment how often must jaw records be obtained
3 times
What are the steps where you need to take new jaw records
- Dx casts for tx planing
- Master casts for framework fabrications
- Master casts for setting teeth
- Remount after RPD acrylic processing
Appointment sequence for jaw records
- Verify midline
- Incisor edge position (BL positioning of teeth)
- Facebow
- Determine VDO
- Decide MIP or CR
- Occlusal registration
When should you hand-articulate
if posterior contacts are present and stable- most accurate ( more than bite reg)
What are the different occlusal schemes
- Balanced
- Anterior guidance
- Group funciton
How do you determine what occlusal scheme to follow
- Kennedy class
- Opposing arch (partial edentulous, dentate or completely edentulous)
Rule 1= The occlusal pattern of remaining natural teeth in mouth dictates occlusion in RPD when no pathology present
Rule 2= The most compromised (weaker arch) dictates the occlusal scheme)
How do you know whether to mount in MIP or CR
- MIP when stable posterior contacts are present (this is a tooth dependent position).
- CR is stable and reproducible- good for when missing posterior contacts
The occlusal pattern of the remaining natural teeth should be followed except when
- Pathology (TMD issues)
- Contacts aren’t stable and/or reproducible
- Not esthetically or functionally acceptable for pt
Signs of occlusal problems are
- Severe tipping
- Premature contacts
- Significant slide from 1st contact to MIP
- Occlusal trauma (mobility/thick PDL)
- Neuromuscular disturbances/ TMD signs
Opening the VDO does what to the patients arc of closure
smaller
Changing the VDO can be done how
complete denture
-Fixed prosth
Mainintaing existing VDO can be done how
- Occlusal adjustment of existing teeth (enameloplasty)
- Harmonize occlusion with direct restorations
- Extract problem posterior teeth
Change in VDO with fixed requires what steps
- Diagnositic occlusal splint- observe for TMD symptoms
- Dx wax up in increased VDO
- Provisional crowns for time in new VDO (if they break then new VDO may not be well tolerated)
VDO in a person with no posterior contacts is determined by
dentist (height of wax rims)
When the completely edentulous arch is the weakest what is the occlusal scheme
balanced (working and balancing contacts)
Why is balanced occlusal scheme useful in completely edentulous arches
-avoids unbalanced occlusal stresses and trauma
When kennedy class I is the weakest arch which occlusal scheme is suggested
balancing (working and non-working contacts)
What is the occlusal scheme for a kennedy class I or 2 with a dentate arch
working contacts only
Occlusal scheme for Kennedy class IV denture
no anterior guidance by denture teeth (dislodges denture)
Jaw records for the fabrication of the framework need to be done when and dont need to be done when
Need to be done when
-RPD + Dentate arch
Don’t need to be done when
-RPD + Completely edentulous arch
Why do you not need to do jaw records before the framework when you have a completely edentulous opposing arch
-Can adjust the heights of all the teeth (will not interfere with framework)
Jaw records before the framework fabrication is helpful to the lab because it
- Determines the thickness and outline of rests
- Placement of minor connectors
- Thickness and placement of retention lattice
Jaw records before the framework fabrication is helpful to the dentist because it
Less adjustments chairside (less intereferences)
How do you do new jaw records after framework fabrication
- Place traid over the latticework with wax rims
- New bite reg (only need wax rims if you can’t hand articulate
For the jaw records after framework fabrication make sure the RPD record base doesn’t
- Contact opposing natural teeth or tissue
- Interfere with VDO
- Has space for bite reg material
Different bite reg materials include
- Wax (baseplate or aluwax)
- Thermoplastic compound
- PVS (regisil and virtual)
- Polyether (ramitec)
How to remove the PMMA record base after the case has been mounted after framework fab.
- Remove wax rims
- Heat to soften acrylic record base
- Remove with hemostat
How are posterior denture teeth selected size wise
measure distal of canine to incline of ramus
