Class II amalgamrestorations Flashcards
What is a class II
missing one wall
positive ledges and consequences
(overhangs)
- excess material will have plaque retentive factors
increases
- increases possibly of recurrent caries and periodontitis
negative ledges and consquences
insufficient restorative material placed
Ledge between tooth and restoration surface
- leads to plaque retentive factor
purpose of matricies
- contain restorative material in cavity
aid in formation of contact point with adjacent material ( loss of contact point leads to stuck food and increased risk of gingiva or periodontal issues/recurrent caries) - form a tight seal at the floor is the proximal box to prevent overhangs or ledges
- provide anatomical contour and smooth cleanable surface
important features of matricies
thin - 0.05mm to allow contact point formation
- smooth
- srong
- capable of close adaptation
- allow contact point to be replaced
what are most matrices made of
stainless steel
types of marticies
circumferential
sectional
transparent strips (mylar)
celluloid crown formers
circumferential matricies
wrap around full circumference of the tooth
- can be used with or without retainer
examples of circumferential matricies
siqveland
toffelmire
promatrix
when are circumferential matrices without a retained used- with commercial eamples
when more than one wall missing and larger cavitities
- automatric
- supermat system
- copper rings
sectional matricies
only cover a section of the tooth
retained by a ring impinging into the embrasure
band is curved and coated to help form a shape
when are sectional matrices used
only in composites
commercial examples of sectional matricies
palodent v3
garrison composi- tight system
wedges
used with a matrix band with adjacent tooth present
function of wedges
creates seal between matrices and tooth
aid in depressive papilla down and away from cavity margins
helps aid adaptation
