Cavity design is an important step in tooth preparation.Slideshare also shows G.V black classification of cavity(class 1 to class 6). Steps in preparation of class 1 ad class 2 cavity.
2. DEFINATION -
CAVITY DESIGN IS ESSENTIALLY A BOX IN FORM OF
FLOOR [PULPAL] AND FOUR WALLS.
THREE TYPES OF CAVITIES-
smooth surface cavities
root cavities
pit and fissure cavities
3. TOOTH PREPARATION WALLS
Internal wall- preparation which
Is not extended into external surface.
Pulpal wall
Axial wall
External wall- wall in the prepare
Tooth that extends into external surface.
Floor or seat
fascial wall
Distal wall
Lingual wall
4. TOOTH PREPARATION ANGLE
Line angle- it is a junction of two surfaces
of different orientations along the line.
Point angle-it is a junction of three planes
surfaces or three line angles of different
orientation.
Cavosurface angle- formed by junction of
prepared tooth wall and external surface of
tooth.
7. SIMPLE COMPOUND AND COMPLEX
TOOTH PREPARATIONS
SIMPLE- if only one surface is involve
example occlusal preparations.
COMPOUND- if two surfaces are involved
example mesio-occlusal preparations.
COMPLEX-if preparation involve more than
two surface example MOD preparations.
8. G.V BLACK CLASSIFICATION OF CAVITY
[THE GRAND OLD MAN OF DENTISTRY]
CLASS 1 CAVITY
CLASS 2 CAVITY
CLASS 3 CAVITY
CLASS 4 CAVITY
CLASS 5 CAVITY
9. G .V BLACK CLASSIFICATION OF CAVITY
CLASS 1 RESTORATIONS
All pit and fissure restorations are class 1 and are
assigned to three groups as follows-
restorations on occlusal surface of premolars and molars.
Restorations on occlusal two third of the facial and
lingual surfaces of molars.
restorations on lingual surface of maxillary incisor.
CLASS 2 RESTORATIONS
restorations on proximal surfaces of posterior teeth are
class 2.
10. CLASS 3 RESTORATIONS
Restorations on the proximal surfaces of anterior teeth that do
not involve the incisal edge are class 3.
CLASS 4 RESTORATIONS
restorations on the proximal surfaces of anterior teeth that do
involve the incisal edge are class 4.
CLASS 5 RESTORATIONS
Restorations on gingival third of the facial or lingual surfaces of
all the teeth except pit and fissure lesions are class 5.
CLASS 6 RESTORATIONS
Restorations on the incisal edge of anterior teeth or the
occlusal cusp heights of posterior teeth are class 6
11. CLASS 1 CAVITY PREPARATION
Need to provide increased resistance – resistance to fracture of
teeth.
Enter the bur in distal pit area [ inverted cone diamond bur –
parallel with the long axis of crown] –permits better vision.
The mesio-distal length will be prepared.
Pulpal floor initial depth 1.5mm -0.2mm inside DEJ.
Lingual facial depth could be greater 1.75mm.
Cuspal and marginal ridge area preservation as much as
possible.
Outline form should be conservative as possible.
12. Extension toward cusp tip should be as minimal as
possible.
Fascial and lingual extension and width are directed
by the caries ,old restorative material or fault.
1.6 mm thickness of marginal ridge for premolars and
2mm for molars.
Extending the outline form to sound tooth structure,
remaining caries should be removed.
13.
14. CLASS 2 CAVITY CONVENTIONAL DESIGN
OCCLUSAL STEP-
-similarly like class 1
-conservative connection between occlusal and proximal
portion.
-1.5 mm initial occlusal depth
-Initial extension toward the proximal area
-Go through the marginal ridge, initial pulpal floor depth
exposing the DEG
-DEG serve as a guide for preparation.
-Inverted cone diamond, parallel with long axis of teeth
crown – occlusal convergence.
15. PROXIMAL BOX
Faciolingual width as narrow as possible.
Initial depth 1.5mm than follows the rise and fall of the
underlying DEG.
Pulpal floor relatively flat.
Preservation of cuspal area.
Not to cut the adjacent tooth.
Ideally there is no preparation beyond the proximal
contact.
Bur always parallel with the long axis of teeth.
Axial wall 0.2mm inside DEG.
16. Inverted cone diamond resulted occlusal convergency.
Remove gingivally any unsupported enamel margins.
PREPARATION ON THE ROOT-
90 degree cavosurface margin
Depth is 0.75-1mm