1. Welcome
To
Dentistry!!
Class 1 Amalgam
Restorations (#30)
Sam Christensen
B.A., D.D.S. Class of ‘05

2. Location of Class I Cavities
 Pit and fissure cavities on the occlusal
surfaces of pre-molars and molars

3. #30?! Which one is that??
#6
#19
#30

4. Class “Everything Else”
 Class 2: In the contact areas between
back teeth
 Class 3: In the contact areas between
front teeth
 Class 4: Contact areas between front
teeth involving the incisal edge
 Class 5: At the gumline
 Class 6: On a cusp tip

5. Review of the Seven Steps in
Cavity Preparation
G.V. Black’s Seven Steps
• Establish Outline Form
• Obtain Resistance Form
• Obtain Retention Form
• Obtain Convenience Form
• Remove Remaining Caries
• Finish Walls and Margins
• Cleansing of cavity

6. Criteria for a Class I
Amalgam Preparation
 Outline Form
 Smooth and fluid
 No sharp angles
 All pits and grooves
removed, dovetails extend
into buccal, lingual,
proximal grooves
Preparation centered on
central developmental
groove

7. PRIMARY GROOVES MARKED

8. CORRECT OUTLINE FORM

9. Isthmus just wide enough to accept
#1 condenser

10. Marginal ridge walls 1/2 distance from
mesial and distal pit to the crest of each
marginal ridge

11. Review of the names of
Class I Preparation Walls

12. Criteria for a Class I
Amalgam Preparation
•Internal Form Bucco-Lingual View
•Buccal and Lingual Walls
are Parallel to each other and
to the Long Axis of the
Crown (Provides retention)
•Buccal, Lingual, and
Proximal Walls meet Pulpal
Floor at sharp angle
•Buccal and Lingual Walls
meet Proximal in smooth,
rounded form

13. Long
axis of
the tooth

14. Long axis of
the crown

15. PERPENDICULAR IN BUCCO-
LINGUAL DIRECTION

16. PERPENDICULAR IN MESIAL-
DISTAL DIRECTION

17. BUR ALIGNED WITH THE LONG
AXIS OF THE TOOTH- WRONG!
The floor of the
preparation
could reach the
pulp!

18. Bur aligned with
long axis of
the crown -
CORRECT!

19. •Pulpal Floor mesio-distally is flat and
perpendicular to the long axis of the tooth

20. Caries removal with 330 bur
 ideal depth is 1.5 mm when smooth and
finished CONTROL THE DEPTH OF
YOUR PREPARATION
 at this step, go to depth of 1 mm
 extend up to mesial and distal pits

21. Caries removal with 330 bur

22. Extension and Smoothing with 56 bur with high
speed handpiece

23. Rashad’s First Prep

24. Good Prep

25. Questions?

26. University of the Pacific
School of Dentistry