1. ALL CERAMIC RESTORATIONS
dr shabeel pn
ALL CERAMIC RESTORATIONS

2. Complete ceramic crown
Should have relatively even thickness circumferentially
About 1 to 1.5mm thickness needed to create esthetically pleasing restoration

3. Excellent translucency Good tissue response
Advantage
Superior esthetic
Excellent translucency
Good tissue response
Conservative reduction of facial surface
Appearance of restoration influenced by color of luting agent
Disadvantage
Reduced strength of restoration
Significant tooth reduction
Difficulty in obtaining well fitting margin
Not effective as retainer for fixed prosthesis
Wear observed on functional surface of natural tooth

4. When more concervative restoration can be used
Indication
Areas with high esthetic requirement
Tooth should be relatively intact with sufficient coronal structure to support the restoration particularly incisal area
Centric contact must be in an area where porcelain is supported by tooth structure
contraindication
When more concervative restoration can be used
If occlusal load is unfavourable
Contra

5. Preparation Armamentarium Narrow round tipped tapered diamond
Football shaped diamond
Finishing stones and carbide
Mirrors and periodontal probe
Explorer chisels hatchets
handpiece

7. Facial reduction Placing depth orientation groove
One depth groove in middle of facial wall and one each in the mesiofacial and distofacial trancitional line angle
Depth is 0.8mm to allow finishing
Cervical component parallel to path of placement and incisal component parallel to original contour of the tooth
Reduction is performed on half at a time

9. Lingual reduction Football shaped diamond
Selected path of placement has been transferred from cervical wall of facial preparation
Place depth groove in middle of cingulum wall
Margin should follow free gingival crest
Should not extent too far subgingivally

10. Chamfer preparation and finishing
1mm wide smooth continuous and free of any irregularity
A 90 degee cavosurface angle is optimal
Objective is to direct stress parallel to path of placement
A sloping shoulder result unfavourable loading of porcelain
Round any remaining sharp line angle to prevent wedging action

12. Strengthening mechanism of dental ceramic
Fabrication defect
Created during processing
Consist of voids porosity microcrack
Surface crack
Induced by machining
Flaw effectively determines the fracture resistance of restoration

13. Crystalline reinforcement
Introduction of high proportion of crystalline phase
A crystalline phase with greater thermal expansion coefficient produce tangential compressive stress near crystal matrix interphase
Such tangential stress tends to divert the crack around particle

14. Chemical strengthening
Relies on the exchange of small alkali ions for larger ion bellow the strain point of ceramic
This techniqe is diffusion driven and its kinetic are limited by time temperature and ionic radius of exchanging ions

15. Stress induced transformation
Zirconia is monoclinic at room temperature and tetragonal at 1170 degree
Stress triggers transformation from tetragonal to monoclinic zirconia
This leads to strengthening as a result of increase in grain volume in the vicinity of the crack up

16. Glazing
Addition of surface glaze
The principle is formation of low expansion surface layer at a high temperature
Self glazing consist of an additional firing in air after original firing without application of a low expansion glaze

17. Prevention of stress corrosion
Baked on metal foil may reduce fracture incidence by reducing moisture exposure to internal surface of ceramic
Coating are used also used to reduce stress corrosion of glass ceramic

19. Selection of all ceramic system
Fracture resistance
Promising result if the restoration are confined to lower stress anterior teeth
Esthetic
A knowledge of available ceramic system is needed
Marginal adaptation of system is important
Translucency of adjacent teeth and discoloration must considered

20. A more opaque high strength core ceramic system like inceram or procera are not good choice for highly translucent teeth
Abrasiveness
Potential for abration of opposing tooth particularly in patient with parafunctional habit
Low abration material should be concidered

21. All ceramic partial fixed prosthesis
Inceram alumina for anterior fdp
Lithium disilicate heatpressed ceramic empress 2 cad cam procera system are also suitable for anterior fdp

22. All ceramic foundation restoration
All ceramic is used as foundation restoration for endodontically treated teeth to overcome esthetic problem associated with metal post and core system

23. Resin bonded ceramic
Performance of all ceramic restoration has been enhanced by use of resin bonding

24. Half moon fracture of crown is common form of failure it occure in
Teeth with edge to edge occlusion
When opposing tooth occlude cervical fifth of lingual surface
Teeth with short crown
Teeth with overshortened preparation