Tooth and Mouth prep and Master Impressions

Question 1

what are the 4 phases in a restorative treatment plan

Answer 1

immediate - treat pain , acute infection etc
initial - hygienic and preparatory - establish oral health, BPE, diet caries etc
reconstructive - restorations, implands RPDs
maintenance - is treatment working / ptc coping ?

Question 2

benefits of preparing rest seats

Answer 2

prevents interference with occlusion
favourable surface for support
reduce prominence
proper loading. down long axis as correct angle can be established

Question 3

guide surfaces/planes

Answer 3

creation of parallel axial surfaces so denture limited to one POI
technique sensitive so be cautious but increases stability and reciprocation and prevents clasp deformation

Question 4

tray spacing

Answer 4

when requesting special trays ensure adequate spacing for your chosen material
e.g alginate = 3mm , silicone = 3mm*

Question 5

when should master impressions be taken?

Answer 5

when denture design on mounted casts is finalised

all tooth prep and restorative procedures are complete

Question 6

what handpiece should be used for tooth preparations and altering special trays

Answer 6

slow speed

Question 7

what can be added to peripheries of special trays if they are under extended

Answer 7

greenstick compound or wax

Question 8

polyvinylsiloxane

Answer 8

synthetic elastomer (addition silicon)
sensitive to moisture
available as light, medium or heavy bodied
needs adhesive
GDH uses extrude

Question 9

polyether

Answer 9

synthetic elastomer
sets rigidly so not to be used in severe undercuts
pentamix system for mixing and dispensing
GDH uses impregum

Question 10

Alginate

Answer 10

irreversible Hydrocolloid

needs to be poured ASAP to prevent distortion

Question 11

for CoCr dentures what should casts be poured in

Answer 11

improved stone

Question 12

for acrylic dentures what should casts be poured in

Answer 12

100% dental stone