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71 terms

Restorative- Amalgam Build up and Finishing and Polishing

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#19 Anatomy
3 facial cusps (Mesiobuccal, distobuccal, distal)
2 lingual cusps (Mesiolingual, Distolingal)
2 buccal grooves (MB and DB)
3 Fossae (M, D, C)
2 triangular ridges
Buccal cusps
even in size and height
Distal cusp
higher than marginal ridge of #18
narrower than other cusps
Ginigval floor
extends to facial
Build Up armamentarium
contra angle toffelmire and extended matrix band
anatomical burnisher
Condensing technique
large area
many cavosurfaces
overfill
Marginal ridges
relatively the same height in the same quadrant
Pins*
The dentist may place only the retention pin, nothing else*
help retain the amalgam into the prep when one or more cusps have been lost. are placed in holes that have been drilled entirely within dentin, not enamel
one pin/ cusp missing*
Pin depth
2 mm in dentin with 2 mm exposed
Pin condensing
must be condensed around as it is layered
Types of pins
screw type
cemented
friction lock
Screw
threaded so it can be screwed into the hole
hole is slightly smaller than screw
Cemented Pin
small than the hole in order for room for cement
Friction lock
slightly larger than hole and must be tapped into the hole
Preperation shape
missing DB cusp and groove and all of distal cusp
Rubber dam for #19
one behind, two in front
rubber wedge on mesial of #21
Benefit of contra-angled retainer
can be placed on lingual so the smooth part of the matrix can be adapted to the buccal
also can be angled up over the mand. ant. teeth
Wedges for #19
placed facially for better adaptation
pg 117 pic*
contoured #2 matrix band
Criteria for matrix and wedge
retainer is placed ligually, slots and smaller opending toward ginigva
occlusal .5-1.5 and gingival extension .5-1.0 mm
secure and stable
wedge adapts band snugly without entrapment
proximal contact is visual with adjacent tooth
Condensing pattern
most inaccesible area first
carry two increments to one area at one time using both ends of the carrier
condense toward the proximal contact, but not too much
Anatomy goals
form the central groove where you can rest on intact cusp contours and form the missing cusps last
Never..
permit the amalgam to entirely conver the unprepared tooth cusps
Missing cusps
formed like a mountain, MB can be used as a guide when ironing the other cusps
Marginal ridges
form the height first
form mesial first
marginal ridges should be concave at first
Immediately
evaluate margins with the hollenback
Proximal contacts
resist without fraying
occlusal to middle 1/3, never gingival
continous embrasures
Occlusion
not grossly out of occlusion, should be within curve of spee
Advantages of finishing and polishing
once hardened (24 hours) they ma be perfected (finished) and smoothed (polished)
two seperate steps
Finishing
perfecting
Polishing
smoothing
Benefits of finishing and polishing
improves corrosion resistance
reduces marginal breakdown
makes restoration easier to keep clean
Polishing*
relatively low speed with intermittant strokes under moist conditions to achieve luster
Finishing burs
used for finishing amalgam
different than cutting because of more, smaller, cutting ridges
Flutes
small, cutting ridges on finishing burs
reduces potential for cutting away enamel
Basic set-up
flame
round (large and small)
football or pear
Finishing bur characteristics*
made from steel, prone to rust
smaller flutes than prep bur
have fine mulitflutes
have more flutes per bur than a cavity prep bur
Super-Greenie cup and point
light green with yellow ring
finest grit used last
Green cup and point
are greeen
medium grit
Brownie cup and point*
brown
coarse grit used first
Green stone
gross excess
White stone
perfecting submarginal areas <.2mm
removes enamel
never remove cementum--->sensitivity
Ideal finished amalgam
perfectly reproduced anatomy and even occlusion margins are flush and a surface that is smooth and shiny without lumps and bumps
Finishing
use of instruments or burs to perfect the shape of the amalgam as needed
margins, anatomy, occlusion, contour
Finishing margins
either too much amalgam or too little amalgam
Overextension
bumps up from tooth to amalgam
Flash
extended beyond the margins
Flame
smooth convex surface
used as a hollenback
follow contour
do not remove tooth
Slow speed handpiece
finishing burs
forward
Finishing discs
used for removing flash on class V and buccal or lingual class II
one abrasive side one non abasive side
Abrasive side
adapted to the tooth
grazing strokes
coarse to fine
Coarse discs
darker
finishing
Fine discs
polising
Rinse
between each type of disc
to remove scratches
Gold Knife
overextensions can be removed
shaving similar to hollenback
Gold File
rubbing motion
Submarginal areas
bumps from restoration to tooth
removed with finishing stone (white)
less than .2 mm
do not expose dentinal tubules
Burnished facets
marks that are shiner than the rest of the amalgam and are flattened like the facet of a diamond
high occlusion
don not flatten but contour or deepen fossa
Temperature *
>140
can cause pulpitis, bring Hg to surface-->suceptibility to corrosion and dull cloudy surface
Pear shaped/Football shaped
concave surfaces and ridges
deepen fossae
similar to cleoid
Small round
accentuate grooves
After finishing
all margins flush anatomy is defined and reasonable smoothness
Polishing*
process of removing minute scratches and producing a shiny surface with no visible surface pits
Benefits of polishing
easier to keep clean
Rubber cups, points, discs
used to impregnate the abrasives for polishing
brownies, greenies, super greenies\
contour determines
Abrasives
coarse to fine
rinse between
Slow speed
polishing handpiece
prevents rubber disintegration
Polishing strokes
one off
do not stay in one spot
Points
fossae
Cups
smooth surfaces
Discs
embrasures