CAD/CAM IN FIXED PROSTHESIS

CAD/CAM IN FIXED PROSTHESIS

1. Introduction  -1-8-

In 1963, the term CAD/CAM (the abbreviation for Computer Aided Design and Manufacturing) appeared. Originally invented for the automotive sector and its repetitive parts, it evolved little before adapting to the dental sector and its prostheses manufactured in a single copy.

In 1973, Professor François Duret described a design technique and

prosthetic manufacturing which turned out to be a real innovation for the time: He shared his knowledge in a thesis entitled “Optical Imprint”.

This thesis describes the processes of CAD/CAM or computer-aided design and manufacturing.

Since the 2000s, dental CAD/CAM has become an ecosystem that can be integrated into laboratories or dental practices. These new technologies are becoming increasingly essential in prosthetics laboratories and dental practices, which are gradually equipping themselves with intraoral 3D impression cameras, scanners or direct CAD/CAM systems.

2. Definition of dental CAD/CAM -2-

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a CAD/CAM refers to all equipment used in the digital chain from modeling to manufacturing of dental prostheses. In addition to computer-aided design and manufacturing software, dental CAD/CAM includes, upstream, 3D scanning equipment (scanners) and downstream, numerically controlled manufacturing equipment.

3. CAD/CAM indication

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This technology used both in the laboratory and in the dental office can be applied;    

                                                                                                                            – inlays, onlays, veneers, fixed prostheses (single and multiple).

– Fixed prostheses on implants (glued or screwed), removable prostheses and removable prostheses on implants .  

 These systems are also used in orthodontics, surgery and maxillofacial prosthetics. 

For each family, the manufacturing processes differ but the digital processes remain essentially the same.

4. Components of the -3-4-5 –

Dental CAD/CAM includes:

3D scanning, computer-aided design and computer-aided manufacturing.

It is important to know that manufacturing equipment is of two types: 

Machining machines – shaping by material removal – and additive manufacturing machines – shaping by material addition –

1. 3D SCANNING

    3D scanning can be defined as a process of measuring the surface shapes of an object to create a computer file that can be used in a computer. 

This computer file is called a “3D digital model” of the scanned object.

Intraoral scanning

    Intraoral digital capture allows impressions to be taken without going through the mold. Several systems are beginning to be marketed. In addition to eliminating the inconveniences of conventional impressions for the patient, the main gain for the dental digital chain is the precision of the prosthesis by eliminating the imprecision of the impression paste.

Capturing digital impressions directly in the mouth reduces the time taken to produce the prosthesis.

Intraoral camera

2- CAD

Most CAD software for dental prosthesis design, and this is the case for the most widespread software, use a polygonal geometric modeling graphics core. This allows them to directly exploit the data from 3D scanning. The files exported by most dental CAD software are therefore “natively” files in STL format. :

This phase corresponds to the digital development of the prosthesis, that is to say virtual. It can be subdivided into two phases: -A data processing phase -A modeling phase.

CAD/CAM IN FIXED PROSTHESIS

3-FAO

CAM is an essential component in a seamless digital chain. Indeed, CAM is the interface between CAD and the material shaping machine.

All CAM software allows the automatic generation of crown and bridge machining programs, and most go as far as the machining of inlays and onlays. 

 The complete cerec system.

5. The advantages of CAD/CAM -6-

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They are multiple and deserve our attention:

With this type of solution -CAD/CAM- you have access to a completely paperless workflow, whether within your practice or for your prosthetist.     

– The information is organized, easily accessible, more secure , and allows you better traceability .

-This dematerialization of information also saves  time . 

In fact, from acquisition to the laboratory, everything is automated and only takes a few seconds to be transmitted.                                                                                                                                                                                                             

– More risk of deformation , and therefore more risk of bringing the patient back.

6. The different techniques of CAD/CAM

First of all, there are three types of CAD/CAM:

• Direct CAD/CAM  : 

That is, digital impression taking, computer-aided design (CAD) and computer-aided manufacturing (CAM) are  carried out within the practice .

This is the technique used by practices wishing to carry out restorations in one session. This is made possible in particular thanks to the 3D printing of crowns in approximately 1 hour.

• Semi-direct CAD/CAM

 When the  digital impression is taken in the office  but the CAD and CAM are carried out by a prosthetics laboratory.

This is the most widespread CAD/CAM today, where dental surgeons who equip themselves trust their laboratories to create their prostheses.

• Indirect CAD/CAM

 With a chemical-manual impression  (alginate, silicone) taken in the office, which will be scanned for further CAD/CAM by the laboratory.

This is where the laboratory initiates the digital flow within its practice. Extra-oral acquisition on plaster cast models is done in the prosthesis laboratory by optical scanning (with solutions such as the  Imetric range of scanners ).

CAD/CAM IN FIXED PROSTHESIS

7. Materials used in CAD/CAM -6-

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Compared to classical techniques, CAD/CAM offers a more varied range of materials in order to satisfy all types of restorations. The materials used depend on the manufacturing process adopted by subtraction or addition and are mainly aesthetic materials; resins, ceramics of all kinds (feldspathic, vitroceramic, aluminous, crystalline based on alumina or zirconia) and hybrid materials.

Thus, CAD/CAM has made it possible to highlight materials other than the metal alloys and products used in traditional techniques, which has made all-ceramic restorations more commonplace.

8. The limits of dental CAD/CAM 

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Despite the many advantages mentioned above, many practitioners remain reluctant to adopt CAD/CAM in their daily practice. This can be explained by the following reasons:

• Excessive investment and maintenance costs, especially for young practitioners or small practices. However, the 

market development will ultimately lead to a

 reduction of these costs.

• Unequipped partner prosthetist
• Lack of interest and time required to learn CAD/CAM techniques
• The aesthetic rendering of machined ceramic with masking is often considered inferior to ceramic laminated using traditional techniques.
• Limited clinical indications

9. Conclusion -7-

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Technology has played a significant role in the evolution of dentistry by improving working conditions in both dental offices and dental laboratories. CAD/CAM in dentistry is a notable advancement. It is simply the digital design of dental appliances, crowns and others using CAD, and the production of these products using CAM. Thanks to the precision and reliability of modern manufacturing processes, not to mention the accuracy and efficiency of 3D scanning, the manufacturing of dental objects has become much more powerful, especially in terms of quality.

CAD/CAM IN FIXED PROSTHESIS

BIBLIOGRAPHY

1- WWW.3D-TOTEM.FR

2-THESES 2014-TOU3-3002 CAD/CAM IN DAILY PRACTICE IN THE DENTAL OFFICE.

3-HAL ID, DUMAS 01961230-2018 UNIVERSITY OF PARIS

4-COMPUTER-AIDED MANUFACTURING IN PROSTHESIS 6045-2013

5-GUIDE TO DENTAL CAD/CAM CNIFPD.FR-guide cad-components html.

6-3D-TOTEM.FR THE ADVANTAGES OF CAD/CAM FOR THE DENTAL PRACTITIONER

7-OWANDY.FR-CAD/CAM DENTAL-

8-HAL ID, hal-01931924. University of Lorraine. All ceramic in direct dental CAD/CAM. 

CAD/CAM IN FIXED PROSTHESIS

  Wisdom teeth can be painful if they are misplaced.
Composite fillings are aesthetic and durable.
Bleeding gums can be a sign of gingivitis.
Orthodontic treatments correct misaligned teeth.
Dental implants provide a permanent solution for missing teeth.
Scaling removes tartar and prevents gum disease.
Good dental hygiene starts with brushing twice a day.
 

CAD/CAM IN FIXED PROSTHESIS