CAD/CAM and the digital workflowCAD/CAM and the digital workflow

Improved Materials

Lost wax casting

Hard ceramics

CAD/CAM system

Manufacturing methods Movement from lost wax casting to

dental CAD/CAM

Application of science to dentistry

CAD/CAM made it possible to work with a new generation of hard ceramics in dentistry. These materials cannot be cast so therefore must be machined. In order to machine something a cutting path is required. The cutting path is generated from digital scanned data.

SCAN THE OBJECT

CREATE DIGITAL DATA POINTS

GENERATE CUTTING PATH

MACHINE REPLICA OBJECT

Application of science to dentistry

CAD/CAMWhat is dental CAD/CAM?

Dental CAD/CAM is the process by which the model of a prepared tooth is scanned. This data is then used to generate the coping design (CAD) which in turn is used to generate a cutting path for manufacturing the coping (CAM).

Computer Aided Design (CAD) and Computer Aided Manufacture (CAM) in restorative dentistry can be used to:

Reduce production time for copings and frameworks; increasing overall productivity

Introduce consistent and measurable accuracy Provide evidence of product quality

CAD/CAM technology

Scanner- digital impression of the prepared teeth

Software – CAD- digital cast on the screen

- virtual design of the model Milling unit – CAM

- computer aided milling unit (cnc)- grinding process

Green processing Milling of presintered ceramic blocks advantage: easy to process, grinding instruments do not

have to be replaced that often disadvantage: porous presintered zirconia shape shrinks

during final sintering- enlarged substructures= software calculated

Hard processing Milling of dense sintered ceramic blocks Takes more time, grinding instruments wear off

HIP= Hot Isostatic Press : special sintering technique High temperature and pressure applied to densify the

material, gaining 20% more in strength

Frameworks zirconium oxide

In clinic - the dentist purchases an intra-oral scanner, the cutting machine and the consumable materials. All the work is done by the dentist at the clinic. Mainly suitable for full crowns, inlays and onlays.

In lab - the laboratory purchases a scanner, cutting machine and consumables. The dentist sends the patient's impressions and prescription to the lab. The lab scans models of the prepared teeth, designs the restoration and machines the restoration.

CAD/CAM methods

Centralised machining - in this situation the lab purchases or leases a scanner only. Again, the dentist sends the patient's impressions and prescription to the lab. The lab scans models of the prepared teeth and designs the coping and then sends this data off to an external machining centre. The machined coping is returned to the lab for veneerig.

Centralised scanners and machining - the laboratory sends the model away to the external centre to be scanned. The coping is also designed and machined at the external centre. The model and coping are sent back to the lab for veneering.

CAD/CAM methods

Non-contact sensor:

optical: laser point, laser stripe, white light, fotogrammetry

Contact sensor:

mechanical

Procera-Centralised machining

Stockholm/ Sweeden

Making a sectioned cast in the lab

Scanning the die and the cast CAD-data sent to central

machining center (checking) Milling starts in 19 minutes Copings (hand) packed and

mailed delivered within 5 days First patient 1985 (1994)

Katana-Centralised machining

Semmelweis Laboratory

• Scan-Measuring unit

• Engine-Milling and

grinding unit

• Therm-Sintering unit

• Elements-Materials

Everest-in lab

Software User interface

Light beam projection

15 projection

sequences

The rotary plate

moves on its vertical

and horizontal axis

during this process

CAD- Software

The preparation limit is automatically detected

Design

Decision guidance

Form of margins

Juncture region

Metal margin

Framework thickness

3-D virtual view of the occlusion on the screen The distances between occlusion and framework

construcion are shown with different colours. Easy, quick and safe design of frameworks in

connection with the virtual wax knife.  

Virtual wax knife- Can be used to process the virtual framrwork in three dimensions on

the screen- Precise addition or removal of virtual material enables quick and

precise waxing

Design

Design

Cantilever bridge Bridge for veneering

CAM Engine 5-axis technology Ensures secure milling of

undercuts• The wide degree of

freedom during the milling process enables complex geometry

• Engine speed5.000 – 80.000 min-1

Engine

Simultaneously controlled 5-axis technology

Thin crown margins and best marginal fit

The wide degree of freedom during the milling process enables complex geometry

Engine speed

5.000 – 80.000 min-1

Cerec-in clinic

Intraoral scanning-no impression Digaital images of tooth and opposing arch

CAD and CAM

Milling the crown

20 minutes chairside

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