With the conventional impression procedures, lost-wax-casting technique in the production of metal castings or frameworks, their accuracy is greatly influenced by the properties of the impression materials, investment and casting alloy. Because traditional procedures are time consuming, efforts have been made to replace these with computer-assisted procedures.

1. Metal Free CERAMICS
Dr Sunil Kumar Mishra
DEPARTMENT OF PROSTHODONTICS

2. Need for CAD/CAM
With the conventional impression procedures, lost-
wax-casting technique in the production of metal
castings or frameworks, their accuracy is greatly
influenced by the properties of the impression
materials, investment and casting alloy.
Because traditional procedures are time consuming,
efforts have been made to replace these with
computer-assisted procedures.

3. Milling of dental restorations from a block of base
ceramic is proposed as an alternative for
fabricating restorations.
To produce milled restorations with accurate fit,
digitization of the prepared tooth surface and
converting the data into control signals for
computer-assisted milling is used.

5. CAD/CAM SYSTEMS
All CAD/CAM systems consist of three components:
1) A digitalization tool/scanner (Scanning)
It includes the data collection tools that measure
three dimensional jaw and tooth structures and
transform them into digital data sets.

6. 2) Software for data processing (Designing)
Depending on the application, produces a data set
for the product to be fabricated. With such
softwares, crown and fixed partial dentures (FPD)
frameworks can be constructed.

7. 3) A production technology (Milling)
It transforms the data set into the desired
product.

8. Silica Based Ceramics
Grindable silica based ceramic blocks are
offered by several CAD/CAM systems for the
production of inlays, onlays, veneers, partial
crowns and full crowns
• It is usually available as monochromatic blocks
• Various manufacturers now offer blanks with
multicoloured layers [Vitablocs TriLuxe (Vita),
IPS Empress CAD Multi (IvoclarVivadent)], for
the purpose of full anatomical crowns.

9. Lithium disilicate ceramic blocks
Full anatomical anterior and posterior crowns,
copings in the anterior and posterior region
and for three-unit FPD frameworks in the
anterior region due to their high mechanical
stability of 360 MPa

10. Glass Ceramics
Glass ceramics are particularly well suited to
chairside application due to their translucent
characteristics, similar to that of the natural
tooth structure.
Provides esthetically pleasing results without
veneering.
Etchable with hydrofluoric acid due to their
higher glass content – can be inserted very
well using adhesive systems.

11. Infiltration Ceramics
Grindable blocks of infiltration ceramics are
processed in porous, chalky condition and
then infiltrated with lanthanum glass.
All blanks for infiltration ceramics originate
from the In-Ceram system (Vita) and are
offered in three variations:
• In-Ceram Alumina (Al2O3)
• In-Ceram Zirconia (70%Al2O3, 30% ZrO2)
• In-Ceram Spinell (MgAl2O4) 81

12. In-Ceram Alumina (Al2O3)
Suitable for crown copings in the anterior and
posterior region, three-unit FPD frameworks
in the anterior region
In-Ceram Zirconia (70% Al2O3, 30% ZrO2)
Suitable for crown copings in the anterior and
posterior region, three-unit FPD frameworks
in the anterior and posterior region. Suitable
for discolored teeth due to its superior
masking ability

13. In-Ceram Spinell (MgAl2O4):
Highest translucency of all oxide ceramics and
is thus recommended for the production of
highly aesthetic anterior crown copings, in
particular on vital abutment teeth and in the
case of young patients

14. CAD/CAM SYSTEMS
CEREC
• Optical scan of the prepared tooth with a
charged-coupled device (CCD) camera, and
the system automatically generates a 3D
digital image on the monitor
• Then, the restoration is designed and milled

15. CEREC inLab
It is a laboratory-based system.
Working dies are laser-scanned and a digital
image of the virtual model is displayed on a
computer screen.
After designing the coping or framework, the
laboratory technician inserts the appropriate
ceramic block into the CEREC inLab machine for
milling.
After milling, the technician manually inspects
and verifies the fit of the milled coping or
framework on the die and working cast.

16. The coping or framework then is either glass-in
filtrated (Vita In-Ceram) or sintered (zirconium
oxide or aluminium oxide), and the veneering
porcelain is added

17. Procera
 Procera/AllCeram was introduced in 1994
 Uses an innovative concept for generating alumina and
zirconia copings.
 The master die is scanned and the data is send to the
processing center.
 After processing, the coping is send back to the lab for
porcelain veneering.
 The recommended preparation marginal design for a
Procera/AllCeram restoration is a deep chamfer or
shoulder with a rounded internal line angle and a well-
defined cavosurface finish line.
 The recommended coping thickness is 0.4 mm to 0.6
mm.

18. Lava
• Lava system Introduced in 2002.
• It includes a mobile cart, a touch screen
display and a scanner with camera at the end.
• Camera has LEDs and lens systems
• Data-send through wireless to the laboratory
where the die is cut and margins are marked
digitally

19. Advantages of using CAD/CAM technology
1) application of new materials
2) reduced labor
3) cost effectiveness and
4) quality control.

20. Drawbacks
• Need for costly equipment
• Need for extended training
• Technique sensitive
• Inability to image in a wet environment

21. ALL CERAMIC RESTORATIONS
Porcelain Jacket Crowns
 Hi-Ceram
Leucite Infiltrated Ceramics
 Duceram LFC
 OPTEC HSP
Castable Ceramics
 Dicor-Cera Pearl
Pressable Ceramics
 Optec OPC
 IPS Empress

22. Cementing of ceramic restorations
• Resin bonding agents
• Increase the retention of all-ceramic crowns and
bridges.
• High bond strength
• Esthetics at margins is better
• Improved translucence
• Increase the fracture resistance and survivability of
ceramic restorations
• Reduces water access to the inner ceramic surface
• Etching blunts the tips of microcracks within the
ceramic, thereby inhibiting crack propagation