12th-Class-III-EDITED Gusto ko lang mag uploaddd

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1. CLASS III

2. Cavities in the
proximal surfaces
of incisors and
canines, not
involving the
incisal angle
CLASS III

3. Lingual
wall
Facial wall
Gingival wall
Axial
wall
Axiolingual
line angle
Axiofacial
line angle
Axiogingival
line angle
Incisal line
angle
Faciogingival
line angle
Linguogingival
line angle
Axioincisal
point angle
Axiolinguogingival
point angle
Axiofaciogingival
point angle
WALLS
LINE ANGLES
POINT ANGLES
CLASS III – proximal approach

4. WALLS
LINE ANGLES
POINT ANGLES
Axial
wall
Gingival wall
Facial wall
Incisal wall
Axiofacial
line angle
Faciogingival
line angle
Axiogingival line
angle
Facioincisal line
angle
Axioincisal
line angle
Axiofacioincisal point
angle
Axiofaciogingival
point angle
CLASS III –lingual approach

5. INDICATIONS
Class III amalgam preparation is generally reserved for the distal surface of
maxillary and mandibular canines if:
(1) the preparation is extensive with only minimal facial involvement,
(2)the gingival margin involves primarily cementum, or
(3)moisture control is difficult.
For esthetic reasons, amalgam is rarely indicated for the proximal surfaces of
incisors and the mesial surface of canines.
However, amalgam may be used for any Class III restoration that does not involve the
facial surface or undermine the incisal corner.
Access for the tooth preparation is generally from the lingual approach to conserve the
enamel facial to the proximal contact.

6. Advantages of restoring the proximal
lesion from the lingual approach:
1.The facial enamel is conserved for
enhanced esthetics.
2.Shade matching of the composite is
less critical.
3.Discoloration or deterioration of the
restoration is less visible

7. Indications for facial approach include:
1.The carious lesion is positioned facially
2.The teeth are irregularly aligned, making
lingual access undesirable
3.Extensive caries extend onto the facial surface
4.A faulty restoration that was originally placed
from facial approach needs to be replaced.

8. SIMPLE CLASS III

9. Cervical floor is placed 1.0 mm
incisal to the cervical line
2.0mm wide
labiolingually
Height of
preparation
(measured
form base to
tip) is 3.0mm
Simple class lll preparation
is triangular in outline
✓ Base is at the cervical
✓Apex points to the incisal

10. Simple class lll preparation
Axial wall at the cervical
portion is placed 0.75 –
1.0 mm from the
cavosurface margin
incisal portion depth
is 1.0 –1.25mm

11. Simple class lll preparation
Cavosurface margins
are beveled, the bevel
width is 0.5 –0.75 mm

12. COMPOUND CLASS III

13. COMPOUND CLASS III
•Involves the proximal and the
lingual surfaces.
•box –like in form and is
enclosed by the labial, cervical,
incisal and axial line angles.

14. COMPOUND CLASS III
Width of the cervical
floor is 1.0mm
Length of the preparation is
1/3 of the cervico-incisal
length of the tooth
1/3
1/3
1/3
Axial wall is parallel to the
long axis of the tooth

15. COMPOUND CLASS III
Labial wall is parallel
to the long axis of the
tooth and is placed
between the lingual
and labial surfaces

16. COMPOUND CLASS III
•Line angles are definite
•Cavosurface margins are beveled
•Retention grooves are made at
the dentin portion of:
✓ axiogingival line angle
✓axioincisal line angle

17. TOOTH PREPARATION
FOR CLASS III AMALGAM
RESTORATION

18. ▪Punch-cut: a No. 2 bur is used for the entry cut
on the distolingual marginal ridge.
▪No. 1/2 or No. 1 bur should be used when the
tooth or carious lesion is small.
Ideally the bur is positioned so
that its long axis is
perpendicular to the lingual
surface of the tooth but
directed at a mesial angle as
close to the adjacent tooth as
possible. This conserves the
marginal ridge enamel.
INITIAL TOOTH PREPARATION

19. ▪penetration should be at a limited initial axial depth
✓0.5 to 0.6 mm inside the DEJ (crown)
✓0.75-to 0.8-mm when the gingival margin will be on the cementum (root)

20. ▪ Complete the initial tooth preparation by using a No. 1/2 bur to
accentuate the axial line angles, particularly the axiogingivalangle.
▪Rounded internal preparation angles

21. FINAL TOOTH PREPARATION
▪Primary retention form:
✓ boxlike preparation form
▪Secondary retention form :
✓retention groove
✓retention cove
✓lingual dovetail
▪No. 1/4 bur

22. ▪No. 1/4 bur
(0.5 mm thick)
•Depth = 0.25mm

gingival retention
groove at ag line
angle
GINGIVAL
RETENTION
GROOVE
If less retention form
is needed, two gingival
coves may be used at
axiogingivofacial and
axiogingivolingual
point angles

23. Incisal retention cove at
afi point angle
INCISAL
RETENTION
COVE
▪No. 1/4 bur
(0.5 mm thick)
•Depth = 0.25mm

24. ▪A lingual dovetail is
not required in small
or moderately sized
Class III amalgam
restorations.
▪It may be used in
large preparations,
especially those with
excessive incisal
extension in which
additional retention
form is needed.
▪No. 245 bur
LINGUAL
DOVETAIL

25. ▪All the walls of the preparation should meet
the external tooth surface to form a right
angle
▪The completed tooth preparation should be
cleaned of any residual debris and
inspected.
Finish the facial, incisal, and
lingual enamel margins using
hand cutting instrument
(hatchet, chisel or hoe).

27. DESIGNS FOR CLASS III
COMPOSITE
PREPARATION

28. Depending upon the type of dental tissues
involved, the tooth preparation for the
composites can be done in three designs:
1.conventional
2.beveled conventional
3.Modified (minimally invasive)

29. CONVENTIONAL CAVITY PREPARATION
Indication
Lesions present on the root surface
Cavity forming features:
•Box shape
• depth: 0.75mm on root, 0.2mm in dentin
• 90°cavosurface margin is required
• Groove retention can be prepared
0.25mm into the dentin of the
axiogingival line and incisoaxial line

30. BEVELED CONVENTIONAL CAVITY PREPARATION
Indication
-Replacing an existing defective
restoration in the crown
-restoration of large preparations
Cavity forming features:
Similar to conventional, but beveled
enamel margin
• Box shape
• 0.75- 1.25 mm depth
• 0.2 mm in the dentin
• axial wall in convex, following the
external contour of the tooth

31. MODIFIED
(minimally invasive)
CAVITY PREPARATION
INDICATION
small and moderate lesions or faults
CAVITY FORMING FEATURES
• designed to be as conservative as
possible
• walls extent only of the fault or
defect area
•design appears to be scooped or
concave
•no groove retention but bevel the
enamel

32. Outline Form
1.Located within the middle third of the proximal area
2.Length of the preparation is 1/3 of the cervico-incisal
length of the tooth (3mm)
Resistance and Retention Form
1.Box-like in form
2.Width of the incisal floor (0.75-1.0mm)
cervical floor (1.0- 1.25 mm)
3. Axial wall parallel to the long axis of the tooth.
4. Labial wall parallel to the long axis of the tooth and placed
between the lingual and labial surface.
5.Beveled cavosurface margin (0.5 – 0.75 mm)
6.Retention grooves at axiocervical and axioincisal line angles
CLASS III – TYPODONT
0.75-1 mm
1.0- 1.25 mm

33. THANK YOU!