rubber dam, pulp protection, class II Flashcards
advantages of rubber dam
- isolation (moisture control)
- retraction
- access
- visibility
- patient/staff protection
- safety, quality, efficiency
rubber dam for anterior teeth
1st pm to 1st pm
rubber dam for posterior teeth
8 (or one tooth distal) to opposite lateral incisor
clamp for upper left molars and lower 8
12A
clamp for upper right molars and lower 8
13A
clamp for lower molars
3
clamp for premolars
2
butterfly clamp
- single tooth (eg endo)
- class V
- anterior premolars
exceptions to rubber dam
- ortho
- fixed/partial dentures
pulp
loose connective tissue with many cell types, vascular network, and sensory innervation
functions of pulp
- dentinogenesis
- defense
- sensation
- nutrition
main factor responsible for pulpal inflammation and necrosis
bacteria
responses of pulp to noxious stimuli
- inflammation (pulpitis)
- deposition of tertiary dentin
- degeneration and necrosis
vital tissues
respond to stimuli
functions of pulpal protection materials
- protect pulp from thermal, chemical and bacterial stimuli
- seal dentinal tubules and resto margins
- reduce sensitivity
- induce tertiary dentin
- promote pulpal healing
best protection for pulp
healthy dentin
varnish is used with
amalgam
varnish function
- seal dentin and reduce microleakage
- prevent dentin discolouration by amalgam
can you use varnish with composite resin, adhesive systems, or GI
NO (only amalgam!)
another name for calcium hydroxide
dycal
function of calcium hydroxide
- inhibits bacterial growth
- promotes formation of tertiary dentin
pH of dycal
> 9 (HIGH!)
disadvantage of dycal
low resistance to compressive forces
when can you use ca oh2
amalgam, CR, GI
where do you apply ca oh2
only in select areas (deep areas)
*not to be used as a base
varnish is used as a
base (applied all over)
ca oh2 can be used with
RMGI (because CaOH2 isnt strong against compressive forces)
varnish should go ____ RMGI and ca(OH)2 if its amalgam resto
ontop
product name of RMGI
vitrebond
properties of RMGI
- cariostatic (releases f-)
- weak chemical adhesion to enamel and dentin
- good compressive strength
- minimal shrinkage
- low pH
- cytotoxic
how does RMGI polymerize
light cure (30 sec)
function of adhesive system
- retention
- seal
- reduce microleakage
property of adhesive system
cytotoxic
can you use adhesive systems for both Ag and CR
yes
what makes up the adhesive system
- acid etch
- primer
- adhesive
bonded amalgam
adhesive used instead of varnish
when should you use bonded amalgams
larger amalgam restos
bonded MOD amalgam restos on max PM have ____ cuspal deflection
decreased
IRM ingredients
powder = zinc oxide and PMMA liquid = eugenol and acetic acid
function of irm
temporary filling
how long does irm last
up to 10 months
why is irm bad near pulp
eugenol is cytoxic
*use ca oh2 first
can you use irm under CR
no
what should you do if you expose the pulp
- place caoh2
- rmgi
- permanent or temp filling
what is indirect pulp capping
leaving some demineralized or infected dentin near pulp to avoid pulpal exposure
shallow, Ag
liner?
varnish
shallow, resin
liner?
adhesive
medium, Ag
liner?
GI then varnish
medium, resin
liner?
Gi then adhesive
deep, Ag
liner?
caoh2 then Gi then varnish
deep, resin
liner?
caoh2, then GI then adhesive
shallow or medium, rmgi
liner?
no liner
deep rmgi
liner?
ca oh2 only
most common global health condition
untreated tooth decay
stagnant sites
- proximal spaces below contact
- cervical below HOC
- developmental grooves and pits
- surface irregularities/malocclusions
- pre existing restos
factors of pre-existing restos to consider
- finishing/polishing
- overhangs
- fractures
- crowns and bridges
when does protective pulpo-dentinal reaction to enamel lesion start
before bacteria invades dentin
- pulp receives signals through enamel water and odontoblasts that lesion is forming
- pulp makes inflammatory cytokins and odontoblasts trigger 3rd dentin
what happens first: demin or bacteria invasion?
demin happens 1st, then bacteria invades after acid diffuses
pulp starts inflammatory response when lesion is ___
0.5-1mm away from pulp
lesion moves faster in which? enamel or dentin
dentin (5 times faster)
zones of infected dentin
- zone of destruction
- zone of bacterial penetration
zone of affected dentin
zone of demineralization
zone of destruction
outermost superficial dentin that is decomposed, due to acid and proteolytic enzymes
outer carious dentin
- infected
- destroyed
- unremineralizable (bc collagen destroyed)
- dead
- senseless
inner carious dentin
- affected (uninfected)
- demineralized (not destroyed, collagen is intact)
- remineralizable
- alive
- sensitive
matrix metalloproteinases
proteolytic enzymes that degrade ECM
cystein cathepsin
lysosomal protease that degrade ECM
CT-K
triple helical collagenase activity
local pH causes mineral dissolution, which leads to
enzymatic degradation of dentin organic matrix
why is cysteine cathepsin K the most potent mammalian collagenolytic enzyme
has multiple triple-helical cleavage sites
what facilitates activation of MMPs
cleavage of MMP prodomain
are MMPs stable in acidic pH
yes, but their optimal functional pH is neutral
steps to dentin lesion progression (wrt MMPs)
- mineral dissolution
- collagen exposure
- low pH followed by neutralization
- MMP activation and function
- collagen degradation
- irreversible stage
are cystein cathepsins stable in acidic pH
yes, and it is not stable in neutral PH
what is the optimal pH for cathepsin
5.5
steps to dentin lesion progression (wrt cystein cathepsins)
- mineral dissolution
- collagen exposure
- low pH
- cathepsin activation and function
- collagen degradation
- irreversible stage
explain distribution of cathepsin and MMP
cathepsin is sparse and MMP is moderate and evenly distributed
synergistic digestive effect
cathepsins and MMPs work at low pH, then when neutralized, MMPs work
inhibitor of MMP and cathepsin k
sodium fluoride
what can be used to preserve collagen in dentin
chlorhexidine
how far into the tooth is op intervention required
0.5 mm into dentin (past DEJ)
setting reaction for low copper amalgams
produces gamma 1 and 2 phase
what is the gamma 2 phase
Sn8Hg
whats the disadvantage of the gamma 2 phase
- low strength
- high marginal breakdown
- high creep
- high tarnish and corrosion
setting reaction of high copper amalgams
produces gamma 1 phase and the eta phase
what happens if you have moisture contamination in amalgam
- delayed expansion
- voids
- greater corrosion
- weaker resto
lathe-cut amalgam alloy particles
- high positive pack
- requires high packing forces
- minimal sensitivity
- poor packing of particles
spherical amalgam alloy particles
- lower packing pressure
- shorter working time
- no positive pack (poor contact and overhangs)
- more sensitivity
requirements for spherical amalgam alloy
- varnish
- broader packing instrument
- more pre-carve and post-carve burnishing
function of wedge
- separation
- prevent overhangs
- prevent movement of matrix band
- protect gingiva and RD
