Metal Free CERAMICS.pptx

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.

4. 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.

5. 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.

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

7. 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.

8. 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

9. 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.

10. 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

11. 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

12. 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

13. CAD/CAM SYSTEMS CEREC O ptical 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

14. 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.

15. 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

16. 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.

17. 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

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

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

20. 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

21. 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