Mouth Preparation Master Cast Flashcards
what is in phase 1
- relief of pain and infection
- collection of diagnostic data
- develop tx plan
- patient education and motivation
- occlusal equilibration
what is included in collection of diagnostic data
- diagnostic cast
- diagnostic mounting
what is in phase 2
- removal of deep caries and temporary restorations
- extraction of non retainable teeth
- preporosthetic surgery: tuberosity reduction, etc
- periodontal treatment, plaque control
- interim prosthesis: function and esthetics
- occlusal equilibration- might need changes after extractions
what is in phase 3
- definitive endo treatment
- definitive restorative treatment: survey crown, FPD
- occlusal plane correction
what is in phase 4
construction RPD
what is in phase 5
- post insertion care
- periodic recall
- continued plaque control
what is included in mouth preparation
- relief of pain and infection
- remove caries
- extractions, preprosthetic sx
- perio tx, plaque control
- occlusal equilibration
- endo
- definitive restorative tx
- occlusal plane correction
- enameloplasty for RPD
what should you do on diagnostic casts
-preliminary design of RPD
- identify tooth modification areas
what are the 3 steps to enameloplasty for RPD
- develop guide planes
- enlarge embrasures for minor connectors
- lower height of contour
- create undercuts if needed
- prepare rest seats
where should the proximal, ML, and lingual guide planes be
- proximal: adjacent to edentulous areas
- ML: stress- release clasps ML minor connector
- lingual: reciprocal clasp
where should the rest seats be located
occlusal and lingual
what is the sequence that preparations should be done to ensure that they are parallel to path of insertion
- prepare guiding planes
- enlarge embrasures for minor connectors
- reposition the survey line to reduce interferences to framework placement and enable most ideal clasp placment
- confirm survey line lowered enough
when are undercut preps done
when slightly insufficient retentive undercut
what undercut prep is contraindicated
- sloped buccal and or lingual surface
when are undercut preps indicated
slightly insufficient retentive undercut with vertical buccla and lingual surfaces
what do you use to prepare undercuts
round end tapered diamond
when are rest seat preps done
after adequate prep for GP, survey line alterations
how do you check for adequecy of occlusal/ embrasure rest seats
- patient close into beading wax
- measure thickness of wax - must be at least 1 mm
what do you do if you are unable to attain adequate depth within enamel
remove small amount of opposing tooth structure and remake impression of opposing arch
what are the Class III RPD impression techniques for master cast
- residual ridge not provide RPD support
- alginate/stock tray
- alginate/ custom tray
- custom tray/elastomeric material
what impression technique is preferred at UMKC
- custom tray/elastomeric materia
- not border molded
- medium bodied PVS
what is an important source of RPD support
residual ridge
what is the broad stress distribution concept
- distribute occlusal forces over as many teeth and soft tissue as possible
- dont overload teeth or tissue
- increased stability and retention
- less frequent reline
what is the problem with tooth- tissue supported RPDs
-the periodontal membrane allows for 0.25 plus or minus 0.1 mm and the muco periosteum allows for 2.0 plus mm movement
due to the lever effect of the distal extension base on tooth- tissue supported RPDs________
occlusal pressure is concentration on the distal end of the base
what is the solution for tooth/tissue supported RPDs
- equalize support derived from tissue and teeth
- to distribute load to both the natural and artificial dentition and minimize base movement
what is the one step impression
custom tray/elastomeric material
what is the corrected (altered) cast technique
- two step (dual) impression
- step one: impression of teeth and residual ridge
- step two: impression of residual ridge areas using framework
describe step one of the two step impression technique
- alginate/stock tray or alginate/custom tray
- frameowrk fabricated on 1st case
framework is ____ precise in aliginate technique than elastomeric impression
less
describe the step two of two step impression
-sectional trays added to framework
- border molded
- elastomeric material
why is the altered/corrected cast prone to operator error
- lift of distal framework during residual ridge impression
- framework on final case not oriented the same as in the mouth
is there a difference in vertical displacment of final RPD between two technqies
no
describe the one step impression with custom tray
- fabricate tray on working/ diagnostic cast
- apply separating medium to cast: liquid foil not vaseline
- tray extensions: 2-3mm coronal to vestibule depth in both dentate and edentulous areas
- wax spacer placed over tray outline
- tray stops
where is the wax spacer placed in one step
- ~3mm over teeth - red rope wax
- ~1.5 mm over residual ridge -baseplate wax
where are the tray stops
3 widely spaced openings in wax spacer - 3mm openings
- tripod support for tray
what teeth should you not use with tray stops
teeth contacting rests
the residual ridge stops in RPD are similar to ______
complete denture tray
how do you make the custom tray in one step impression
- aluminum foil over wax spacer
- triad tray material adapted over foil/spacer
- polymerize
- add finger rests to tray surface over edentulous areas
- add handle
why do you add finger rests to tray surface over edentulous areas
-stability during impression
- strengthen tray
what tray area is prone to fracture
distal areas
when do you determine final tray extension
at impression appointment
where are PIP tray flanges located
extension and outer surface
what should you do at final tray extension appointment
- border molding movements
- areas where PIP removed, shorten or thin tray
- border mold distal extension residual ridge areas
describe elastomeric impression material
- polysulfide: high tear strength, pour within 1 hour
- PVS: hydrophobic, adequate tissue detail
how do you make the master cast
- box impression
- pour with improved dental stone
what do you do to survey the master cast
- determine path of insertion
- mark abutment height of contour
- measure and mark retentive undercut
how do you determine path of insertion
- guide planes parallel
- equalize undercut
where do you mark the abutment height of contour
facial and lingual
how do you measure and mark retentive undercut
- red line not dot
- approximate inferior edge of clasp
what do you do on the master cast
- survey
- tripod lateral sides of cast
what is involved in the lab prescription
- surveyed cast
- work authorization
- send to QA for approval
- send to lab
- framework fabricated
