1. Features preparation carious cavities different classes in temporary and permanent teeth in children.
Cavity Preparations

2. Indication of Operative Dentistry
Caries;
Malformed, discolored,
or fractured teeth;
Restoration replacement.

3. Tooth-colored restoration
For Class Ⅲ，Ⅳ and Ⅴ，
Esthetic Dentistry
For Class Ⅰand Ⅱ，

4. What are Tooth-colored materials?
What is their working mechanism?
What are the cavity preparation futures for tooth-colored restoration?

5. What are steps for tooth-colored
restoration?
What are the advantage & disadvantage
of tooth-colored restoration?

6. Tooth-Colored Materials
Composite resin
Glass ionomer cement
Compomer

7. Composite Resin Traditional composites Hybird composites
Flowable composites
Condensable composites
Packable
Universal composites

8. Glass Ionomer
Chemical adhesion to dentin
Release Fluoride

9. Compomer
Compomer =
Composite +
Ionomer

10. Dental Adhesion or Dental Bonding
Adhesion is a process of solid and/or
liquid interaction of one material with
another at a single interface.

11. Enamel bonding system
Enamel bongding depends on resin tags
becoming interlocked with the surface
irregularities created by etching.

12. Macrotags: form between enamel rod
peripheries.
Microtags: smaller tags form across
the end of each rod.
Macrotags and microtags are the basis
for micro-mechanical bonding.

13. Dentin bonding system
The difficulties of dentin bonding:
More water---wet bonding
Lower calcification
Richer organic---collagen network
Smear layer

14. The bond strength is primarily related
to micro-mechanical bonding to the
intertubular dentin which occures
between tubules along the cut dentin
surface.

15. Dentin Bonding Agent, DBA
Early DBA were hydrophobic, bonded
directly to the dentin smear layer.
Bond strengths＜6MPa.
Later DBA removed the smear layer but
tended to over-etch dentin.
Bond strengths≈10~12MPa.

16. DBA were chemically modified to be
more hydrophilic.
Bond Strengths≈18~20MPa.
Careful dentin conditioning,
Coupled with hydrophilic primer,
Bond Strength≈22~35MPa.

17. The Development of DBA Enamel etch (1955) Dentine etch (1960)
Treatment of smear layer (1980)
Wet Bonding technique(1990)

18. First generation
Second generation
Third generation
Fourth generation: Total etch technique
Fifth generation: One bottle system
Sixth generation: All in one,2000
Seventh generation

19. Cavity Preparation Three designs of cavity preparation: 1.Conventional
2.Beveled conventional
3.Modified

20. Beveled conventional cavity preparations
are similar to conventional preparation,
in that the outline form has external,
“box-like” walls, but with beveled
enamel margin.

21. Beveled enamel margin

22. Beveled conventional cavity designs for Class Ⅲ, Ⅳ and Ⅴ preparations

23. The advantages :
The ends of enamel rods are more etched
The increase in etched surface results in
a stronger bond
Increase the retention and reduce marginal
leakage and discoloration.
More esthtically

24. Modified cavity preparation
Have neither specified cavity wall structure
nor specified pulpal depth, and have enamel
margins.
Conserve more tooth structure.

25. Modified cavity preparation

26. Initial Clinical Procedure
Local anesthesia
Preparation of the operating site
Shade selection
Isolation of the operating site
with rubber dam or cotton rolls

28. Rubber dam

29. Clinical Procedure Cavity preparation
Acid etching enamel & conditioning dentin
Matrix application
Application of bonding agent
Insertion of composite
Finishing procedures

31. Matrix application

38. Final procedures

40. Cases

43. Conservative Operative Dentistry
Minimal intervention dentistry
is regards as a main stream in caries treatment in the 21st century.

44. Principles of Minimal Intervention dentistry
Remineralization of early lesions
Reduction in cariogenic bacteria, to elminate the risk of further demi-neralization and cavitation
Minimum surgical intervention of ca-vitated lesions
Repair rather than replacement of defective restorations

45. “The day is surely coming, and perhaps
within the lifetime of you young men
before me, when we will be engaged in
practicing preventive, rather than reparative, dentistry. ”
GV Black in 1896

48. Thanks