restorative Flashcards
what should be included in prescription for a canti lever bridge
- please pour imps in 100% stone and mount on semi-adjustable articulator using bite provided
- please construct metal ceramic (NiTi) conventional mesial cantilever bridge, replacing tooth XX. please use tooth XX as abutment and tooth XX as pontic
- Shade XX and ridge lap pontic (or modified if anterior)
- please construct in canine guidance and ensure pontic is free in excursive movements
- please return the bridge with the cast
why is vitrebond used as a lining material
it is a RMGI, it bonds to the dentine but can also bond to restorative material. seals dentine tubules, reduces microleakage and decreases post op sensitivity
why is calcium hydroxide used as pulp cap
it has high ph - bacteria like acidic environment so kills any bugs
also irritating to dentine, causes layer of tertiary dentine to be formed, bridges off base of cavity to pulp
how is a direct pulp cap placed
- pulp will be bleeding, irrigating with saline until bleeding stopped
- once bleeding stopped, irrigation with CHX
- cavity blotted dry with sterile cotton pellets
- dycal placed over pulp
- vitrebond placed over
- restoration placed
what should you check when assessing a crown
i - insertion, can crown easily be inserted, any undercuts
o - occlusion, is it too high in any areas,
m - margins, are there any gaps
a - aesthetics, good colour match
c - contact points to adjacent teeth
if crown makes occlusion too high, what can be done
- reduce height of crown - check with crown callipers that sufficient material to reduce, ensure you dont perforate, need 1.8mm for functional cusp
- ask lab to make new one
- reduce opposing tooth
what are principles of cavity prep
- access caries
- extend access to expose extent at ADJ
- removal of dentinal caries
- modification - removal of sharp internal lines, smooth cavosurface margin angles
what are principles of crown prep
- preservation of tooth tissue
- retention and resistance form
- structural durability
- marginal integrity
- preserve periodontal tissue
name 3 causes of discolouration - 3 extrinsic and 3 intrinsic
extrinsic - tannins from smoking, tea, coffee; chlorhexidine, chromogenic bacteria
intrinsic - fluorosis, tetracycline, non-vital teeth
how does bleaching work
uses carbamide peroxide 10-15% gives 6% hydrogen peroxide - produces free radicals that break down long chains into shorter ones via oxidation - have less pigmentation
what are side effects of bleaching
sensitivity - 60% of ppl will get this and higher risk if sensitivity before bleaching, if gingival recession or high % used
relapse - results wont last forever, need to continue use
restorations wont change colour
gingival irritation - need to ensure tray doesnt extend onto gingiva
what are requirements for internal bleaching
non-vital tooth
good rct
no apical pathology
what is main risk of internal bleaching
external cervical resorption - hydrogen peroxide travels through dentinal tubules and damages PDL - more risk if high % and heat, should seal tubules
what is walking bleach technique
remove GP 1mm below ACJ then place RMGI to seal it off
carbamide gel placed inside tooth then CWR then RMGI - replace this every week, can take 3-4 visits then final restoration
what is inside outside technique
gp removed 1mm below ACJ then sealed off with RMGI
access left open, tray made with palatal recess
gel then placed inside access and tray, replaced frequently throughout week
PT must wear tray 24/7 and have meticulous oral hygiene
