1. DENTAL CERAMICS
Dr.linda maher

2. DEFINITIONS:
Ceramics: materials composed of metallic and non metallic oxide compounds, including porcelain and similar ceramic materials.
Porcelain: tooth colored dental ceramic materials that are composed of feldspar, quartz, kaolin and some pigments
Porcelain actually more closely resembles a glass.

5. DENTAL PORCELAIN HAS THREE BASIC REQUIREMENTS:
1\FUNCTION (strength and biocompatibility)
2\FORM (ability to form complex shapes)
3\ESTHETICS (color , translucency)

6. FORMS OF PORCELAIN TWO FORMS:
1\powder form(mixed with water or water based liquid)
2\paste form
IT IS USED BY DENTAL TECHNICIAN
Porcelain is mixed and worked out to the restoration shape then it is heated to high temperatures (ranging from degree C) to set and harden

7. CLASSIFICATION THREE MAIN GROUPS:
1\mostly glass ceramics have glass matrix with very
2\particle filled glass few crystalline and particles
3\polycrystalline zerconium oxide or aluminum
oxide matrix with fillers
GENERALY:
the more esthetic the ceramic is the more glass is found to it
The polly crystalline types are stronger

8. USES OF CERAMICS IN DENTISTRY
1\CROWNS
2\BRIDGES

9. 3\INLAYS
4\ONLAYS
5\VENEERS

10. PORCELAIN RESTORATIONS
1\porcelain –metal restorations 2\all ceramic restorations

11. 1\Porcelain-metal restorations

12. PORCELAIN METAL RESTORATIONS ARE Restoration that has a metal core over witch porcelain is fused at high temperatures.
Can be used as crown or bridge
Advantages:
Combines the Strength of the metal core and the esthetics of porcelain.
Metal thickness= mm.
BONDING BETWEEN METAL AND PORCELAIN:
Combination of mechanical and chemical bonds

13. Porcelain is applied over the metal in layers:
1\First layer=opaque porcelain(masks the color of the metal).
2\additional layers=
1- body(dentin) layer
2- incisal(enamel) layer
Simulate the natural colors of dentine and enamel of natural teeth.
Glazing is then done to provide a smooth and shine surface.

15. 2\All ceramic restorations
They are Ceramic restorations with no metal core
They are widely used because of their:
Excellent esthetic
Biocompatibility
Low wear rate
Stain resistance
Used for:
Inlay - Onlay -Crowns
veneers rs

16. Although they are very strong they can still fracture under heavy occlusal load

17. Veneers
Thin layers of esthetic materials that are bonded to the fronts of teeth.
Purposes of veneers:
To lighten the color of teeth
To cover stains
To close diastemas
To reshape crooked teeth

18. TYPES OF VENEERS:
1\DIRECTLY PLACED COMPOSITE VENEERS
2\INDIRECT (LABORATORY MADE) CERAMIC VENEERS
BONDING OF VENEER TO THE TOOTH:
1\minimum reduction of the enamel is done
2\acid etching of the tooth and the porcelain veneer
3\bonding agent and adhesive material is used

19. SHADE SELECTION: 1\specific shade guide is used
2\should be taken before tooth preparation
3\taken before rubber dam application
4\teeth should be clean ,free of stain and moist.
5\use natural day light

20. CLINICAL TIPS
1\Avoid acid etchants on ceramic restorations in the patient mouth
2\when providing in-office fluoride treatment to adults with ceramic restorations , avoid the use of acidic (e.g. acidulated phosphate fluoride APF)
Acid etchant and acidic fluoride will roughen the surface of the ceramic

21. 3\ it is important to identify junction between the tooth and any ceramic restorations within the patients mouth when doing scaling and root planning procedure (to avoid chipping of the margins)

22. Porcelain failures
Small cracks when the porcelain is under high occlusal loading.
Problems between bonding of porcelain and metal.

23. Computer-Assisted Machining
Advances have led to the development of sophisticated computer-assisted design and computer assisted machining (CAD/CAM).

25. A scanner makes an impression of crown preparation and opposing teeth
the computer designs the crown to fit the teeth
this design is given to a computer controlled machine that uses diamond instruments to mill an all ceramic crown.

26. Advantages of this technique:
Anesthesia is only needed for the first visit
No need for impression
No need for cast to be poured
No need for temporary crown

27. Thank You