37. General rules of cavity preparation.

Question 1

1. What are Black rules of cavity preparation?

Answer 1

• Black: EXTENSION FOR PREVENTION→ aim was to prevent the secunder caries
  ◦ the border of the cavity should be extended to areas that are normally self- cleaning, or cleansable, therefore healthy tooth structure can be removed

Question 2

2. What are the principles of cavity preparation nowadays?

Answer 2

During the years the Black rules were modified many times → principles nowadays:
- Healthy tooth structure should be preserved
- All fracturable enamel should be removed
- All caries/faults should be involved
- Good polishable position
- The outline of the filling should be shortened

Question 3

3. Preparation techniques
   a/ What are the 3 forms for cavity preparation?

Answer 3

1/ Conventional form
2/ Beveled conventional form
3/ Modified form (adhesive or minimal invasive)

Question 4

3. Preparation techniques
   a/ Characteristics of CONVENTIONAL form

Answer 4

• For amalgam, inlay/onlay, root surface caries
• Macroretention
• Box-like cavity
• Special enamel margin
• Secondary retention are used very often

Question 5

3. Preparation techniques
   b/ Characteristics of BEVELED CONVENTIONAL form

Answer 5

• Old amalgam filling is changed to composite
• Macro- and microretention
• Box form, but enamel margins are beveled for higher microretention

Question 6

3. Preparation techniques
   d/ Characteristics of MODIFIED form (ADHESIVE or MINIMAL- INVASIV)

Answer 6

• No special form
• Only decayed tooth structure will be removed
• cavosurface margin will be beveled
• Composite→Microretention