mouth preparation and master cast

Question 1

patient treatment phase I:

Answer 1

-relief of pain and infection
-collection of diagnostic data (diagnostic cast and mounting)
-develop treatment plan (design RPD)
-patient education and motivation
-occlusal equilibration

Question 2

patient treatment phase 2:

Answer 2

-removal of deep caries, temp restorations
-extraction of non-retainable teeth
-preprosthetic surgery: tuberosity reduction
-periodontal treatment, plaque control
-interim prosthesis: function, esthetics
-occlusal equilibriation, may need changes after extractions

Question 3

patient treatment phase III

Answer 3

-definitive endodontic treatment
-definitive restorative treatment (surveyed crowns if needed, fixed partial dentures, if appropriate)
-occlusal plane correction

Question 4

patient treatment phase IV

Answer 4

construction RPD

Question 5

patient treatment phase V

Answer 5

-post insertion care
-periodic recall
-continued plaque control

Question 6

diagnostic casts

Answer 6

preliminary design of RPD
identify tooth modification areas

Question 7

perform tooth modifications according to

Answer 7

according to RPD diagnostic cast design
-QA worksheet

Question 8

enamoplasty for RPD steps

Answer 8

1. develop guide planes
2. enlarge embrasure for minor connectors
3. lower height of contour
4. create undercuts if needed
5. prepare rest seats (occlusal and lingual: chevron)

Question 9

with developing guide planes for enamoplasty for RPD (step 1) what are the requirements:

Answer 9

-proximal: adjacent to edentulous areas
-ML: stress-release clasps ML minor connector
-lingual: reciprocal clasp

Question 10

with lowering height of contour for enamoplasty (step 3) what are the requirements

Answer 10

-proximal 2/3 circumferential retentive clasp
-reciprocal clasp
-lingual guide plate

Question 11

confirm that the preparations are parallel to path of insertion in what following sequence (guide planes, embrasures, alter height of contour):

Answer 11

1. prepare guiding planes
2. enlarge embrasures for minor connectors
3. reposition the survey line to reduce interferences to framework placement an enable most ideal clasp placement (make sure lowered enough)

Question 12

used when slightly insufficient retentive undercut
-slopped buccal or lingual surface

Answer 12

undercut preparation
(need to reconsider other areas for undercut or need surveyed crown)

Question 13

undercut preparation with

Answer 13

round-ended tapered diamond (where tip of retentive clasp will go)

Question 14

this is done after adequate preparation for guiding planes, survey line alterations

Answer 14

rest seat preparations

Question 15

if you are unable to attain adequate depth with enamel for rest seat

Answer 15

remove small amount of opposing tooth structure and be sure to remake impression of opposing arch

Question 16

master cast class III RPD impression technique/preferred at UMKC

Answer 16

custom tray/elastomeric material
not border molded
medium bodied PVS

Question 17

for master cast extension RPD impression, what is an important source of RPD support and what is important to accurately record

Answer 17

residual ridge important source of RPD support
-important to accurately record max tissue support area

Question 18

concept where
-distribute occlusal forces over as many teeth and as much soft tissue as possible
-not overload teeth or tissue
-increased stability and retention
-less frequent reline

Answer 18

broad-stress distribution concept

Question 19

what is the problem with tooth-tissue supported rpds

Answer 19

due to lever effect of distal extension base, occlusal pressure is concentrated on the distal end of the base

periodontal membrane allows 0.25+/- 0.1 mm (teeth basically)
and
muco-periosteum allows for 2+mm movement (palate or tongue area)

Question 20

what is the solution for tooth/tissue supported RPDS

Answer 20

-equalize support derived from tissue and teeth
-to distribute load to both natural and artificial dentition and minimize base movement

Question 21

master cast: extension RPD impression options

Answer 21

1. custom tray/elastomeric material
   -border-molded tray
   -one step impression
2. corrected (altered) cast technique
   -two-step impression
3. impression of teeth and residual ridge
4. impression of residual ridge areas using framework

Question 22

master cast: altered cast impression step one explained

Answer 22

1. impression of teeth and residual ridge
   -alginate/stock tray or alginate/custom tray

-framework fabricated on 1st cast (framework less precise than with elastomeric impression

Question 23

master cast: altered cast impression step two explained

Answer 23

2. impression of residual areas only
   -sectional trays added to framework
   -border-molded
   -elastomeric material

Question 24

master cast: altered/correct cast steps explained

Answer 24

1. residual ridge removed from 1st cast
   retentive dovetails created
2. framework/impression luted to altered cast
   -cast and impression boxed
   -residual ridge areas poured with yellow stone
3. final cast

Question 25

what method of master cast for extension RPD is a complex technique and prone to operator error

Answer 25

altered/corrected cast

Question 26

one step impression custom tray method explained

Answer 26

1. fabricate tray on working / diagnostic cast
2. apply separating medium to cast (liquid foil not vaseline)
3. tray extensions 2-3mm coronal to vestibule depth in both dentate and edentulous areas

Question 27

on one-step impression for custom tray method, wax spacer is placed over tray outline where

Answer 27

3mm over teeth (red rope wax)
1.5mm over risidual ridge (baseplate wax)

Question 28

on one step impression custom tray, 3mm widely spaced openings in wax spacer provide tripod support for tray

Answer 28

tray stops

Question 29

with tray stops on one-step impression custom tray, use teeth (contacted/not contacted) with rests

Answer 29

NOT contacted

-residual ridge stops similar to complete denture tray

Question 30

with custom tray impression, border mold:

Answer 30

distal extension residual areas

Question 31

with custom tray impressions, use what kind of material

Answer 31

elastomeric impression material
-polysulfide:high tear strength, pour within 1 hour
-PVS: hydrophobic, adequate tissue detail

Question 32

once master cast impression is completed:

Answer 32

box impression and pour with improved dental stone
-survey and everything else