Class II. – classification
• The cavity that is composed of the occlusal
and proximal cavity
• Slot
• Large defects - restoration with the
replacement of cusps
Occlusal cavity Proximal cavity
The cavity composed of two cavities
Slot cavity
• The cavity is limited on proximal surface
only
Access:
From the occlusal surface through the
enamel and dentin
Slot cavity
• The cavorusface margin:
- The cavity is open occlusally within the
proximal ridge.
- Position of the axial walls: axial walls are
0,5 mm orally and 0,5 mm vestibulary
from the contact point (contact area)
- Position of the gingival wall: the gingival
wall is located 0,5 mm subgingivally
Slot cavity
• Retention
- The axial walls are divergent towards
the gingiva
- Vertical retention grooves are prepared
in the axial walls
- A horizontal groove is prepared in the
gingival wall
Slot cavity
• Resistance
- the enamel must be supported with
dentin
- all edges are smoothened (rounded)
- the thickness of amalgam is appr. 2 mm
- the angle betwen the gingival wall and
the pulpal wall is 90°
- the gingival wall is 1 mm wide
Slot for amalgam
• Access to the caries lesion
- go through the enamel wall
- breaking out of the enamel lamella
- excavation of carious dentin
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Pre op
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Access to the cavity
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The matrix and the wedge must be used
For the slot preparation small
instruments are necessary
A magnification (loops) is usefull
Large defects
• When one or more cusps are undermined,
these must be cut and replaced with amalgam
Access: from zhe nocclusal surface
Cavosurface margin: depend on the size and
shape of the defect. It is similar to the
conventional preparation see pictures in the
following slide.
The position of the gingival wall is 0,5 mm
subgingivally
Large defects
• Retention
- Undercuts
- Retention grooves
- Small cavities
- Endodontic cavity in case of endodontically
treated teeth
- Parapulpal pins (small screws – rare)
Large defects
• Resistance
- enamel must be supported with dentin
- all sharp edges must be smoothened
- the gingival wall must be at least 1 mm wide
- the angle between the gingival wall and the
pulpal wall must be 90°
- the thickness of the amalgam must be 4 mm on
the cusp, in other parts of the occlusal surfaces
2mm
Large defects
grooves
The thickness of the amalgam must be 4 mm
Large defects
The angle between both pulpal walls is 90°
The base of zinkoxid phosphate cement
is placed on pulpal walls
Sharp edge
Parapulpal pin
Small cavities for retention, called
sometimes pins (no parapulpal, bud pins)
Endodontic cavity
for retention
Various possibilities of retention
of large restorations
Large amalgam restorations
•
Matrices and wedges are necessary, the occlusal surface must be carved carefully
Composite materials and class II.
• Composite materials can be used in case of
good level of oral hygiene in small and
moderate cavities class II.
• There are some differences in comparison to
amalgam
Preparation for composites
• Cavosurface margin:
The preparation removes the caries lesion, the extention on occlusal
surfaces is not necessary.
We prepare this occlusal cavity only:
- If the old amalgam foling is replaced
- If the dental caries affects also the occlusal surface
- The oblique ridge oblique could be undermined – it is aceptable
- If the occlusal surface is intact the extention into fissures is not
necessary
- The position of axial walls is the same as in the conventional
preparation
- The position of the gingival wall is supragingival
Preparation for composites
Retention
The undercuts and grooves are not prepared
The box is rounded
The enamel is beveled:
On axial walls and on outer edge of the gingival wall
No bevel is prepared in occlusal cavity
The retention:
Microretention: etching, washing, priming, bonding.
Preparation for composites
• Resistance
- No sharp edges in the cavity
- Thickness of the filling is 2 mm on occlusal
surface
- The gingival wall is 1 mm wide
Cavity for amalgam
Cavity for composite
Preparation for composite
The occlusal surface is not involved in this case
You can see beveled enamel in proximal part
of the cavity
The gingival wall is 1 mm wide
The contact area will be made of
composite material
Beveled enamel
Sedelmayer
Small preparation when the cavity is open
on the occlusal surface only within the proximal
ridge is called adhesive slot
In comparison to the slot for amalgam
- no undercuts and groovesw are prepared,
- the gingival wall is situated supragingivally
- the enamel is beveled on the axial walls
and the gingival wall
Matrices for composite materials
• Sectional matrices are optimal
• Circular matrices can be used
also, the restoration of the
contact area is more difficult
Sectional matrices
• Restore one proximal surface
• Made of soft metal
• Have various shapes and size
• They are used in combination with the
wooden wedge and the separation ring
• The separation ring is handled using the
rubberdam forceps
Sectional matrices
Shapes of sectional matrices Separation rings
Rubberdam forceps and separation ring
Placement of the sectional matrice
Sectional matrice in oral cavity
The proximal wall has been built first
The wooden wedge separates teeth, adapt the matrix and
compresses gingiva After building of the
the mesial surface the separation ring
will be placed on the distal surface
Circular matrice and composite
material
The proximal surface has been built
The other layers
follow
Making filling
• Composite filling is made layer by layer
• First the proximal surface id built (see picture
above)
• Than layer by layer are placed. The thickness
of each layer is appr. 1,5 mm. This is and
incremental technique. The reason fot this is:
good polymerization (the material is cured
into the depth 1,5mm)
• Finishing and polishing in usual way follows