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LAB TRIBUNE Dental Tribune Middle East & Africa Edition | 1/2017 B3 ◊PageB2 in different clinical situations. Lava Plus, for example, is a combination of zirconiaandanano-ceramic. CAD/CAMsystems A number of different manufactur- ers are providing CAD/CAM systems that generally consist of a scanner, design computer and a milling ma- chine or 3-D printer. Laboratories are able to receive digital impression filesfromdentistsoruseascannerto create digital models that are used for restorations designing or CAD. Dental scanners vary in speed and accuracy. Milling machines vary in size, speed, axes, and also in which restorative materials can be milled; in this category milling machines could be classified as wet or dry de- pending if the materials require ir- rigation. The development of dental CAD/ CAM systems occurred around 1980 with the introduction of the Sopha system developed by Dr. Francois Duret. A few years after that event, Dr. Werner Mörmann and the elec- tricalengineerMarcoBrandestinide- veloped the CEREC-1 system in 1983, thefirstfulldigitaldentalsystemcre- ated to allow dentists to design and fabricate in-office restorations. Since then, the continuous evolution of systems dedicated to this field has continued and has exponentially in- creasedinthelastdecade.[14] CEREC systems has evolved into CEREC Bluecam scanner;accuracies as close as 17 microns for a single toothhavebeenreportedbyauthors using this system. Recently CEREC Omnicam was introduced offering true colour digital impressions with- out the need of a contrast medium. InarecentstudybyNevesetal.(2013) on the marginal fit of CAD/CAM restorations fabricated with CEREC Bluecam, they compared lithium disilicate single unit restorations to heat-pressed restorations and 83.8 percentofthespecimenshadaverti- cal gap measurement with less or at least75microns.[15] The CEREC InLab CAD software (Si- rona Dental) was designed for dental laboratories for a wide range of den- tal capabilities that can be combined with third party systems. With this software, the dental technician is able to scan their own models using Sirona inEos X5 (Sirona Dental) scan- ner and design the restoration; once thisprocessiscompleted,thefilecan be sent to a remote milling machine oramillingcentreforfabricationina widerangeofmaterials. The Procera system, introduced in 1994, was the first system to provide fabrication of a restoration using a network connection. According to research data the average ranges of marginal fit of this restorations are from 54 to 64 microns.[20] A com- puter integrated crown reconstruc- tion system (CICERO) introduced by Denison et al. in 1999 included a rapid custom fabrication of high- strength alumina coping and semi- finished crowns to be delivered to dental laboratories for porcelain lay- eringandfinishing.[15] Another system that was developed years ago was the Celay system, which fabricated feldpathic res- torations through a copy-milling process. The system duplicated an acrylic resin pattern replica of a res- toration. Zirkonzahn developed a similar system called the Zirkograph in 2003, which was able to copy-mill zirconia prosthesis and restorations out of a replica of the restoration. Some years after, the Cercon system (DENTSPLY Ceramco) was able to de- sign and mill zirconia restorations outofawaxpattern.[1] Almost at the same time that these companies developed the first copy mill prototypes, Lava (3M ESPE) in- troduced in 2002 the fabrication of yttria-tetragonal zirconia polycrystal (Y-TZP) cores and frameworks for all ceramic restorations. With the Lava system, the die is scanned by an optical process, the CAD software designs and enlarge the restoration or framework that is milled from a pre-sintered blank. Studies on mar- ginal adaptation suggest that Lava restorations have a marginal fit that canbeaslowas21microns.[27]Some other systems that were able to mill zirconia were DCS Zirkon(DCS Den- tal)andDenzir.[16] In the last decade, companies have decided to differentiate their prod- ucts by having a full CAD/CAM plat- form or by focusing on specific areas of expertise like CAD software and intraoral scanners; these companies claim to be open platform because theirsystemsallowtoexportuniver- sal files such as STL or OBJ (Fig. 5) to be used with the majority of nesting softwares and milling machines that areabletoimportthem. Defenders of closed platforms claim that the integration of different CAD/CAM systems does not allow for a good integration between parts and probably leads to the incorpo- ration of fabrication errors; at this point no research about systems in- tegration is available. Table II shows some of the systems used for dental CAD with their file output; Table III shows some of the most used CAM systems with their material recom- mendationsandcapabilities. Some of the main concerns from cli- nicians about all-ceramic CAD/CAM restorations accuracy of fit are: scan- ning resolution, software designing limitations, and milling hardware limitations of accuracy. Clinicians’ andtechnicians’experiencewiththe CAM/CAMsystemintegrationisalso a key factor for fabricating good res- toration; the computer software per se will not allow an inexperienced operator to create an excellent den- talrestorationfromscratch.[18] Discussion Several advantages can be drawn from including CAD/CAM dental technology, 3-D scanning and the use of mill materials for all-ceramic restorations. Even though clinical studies have shown that marginal fit of CAD/CAM restorations is com- pared to conventional restorations thefabricationofdentalrestorations is still a complex task that requires experience,knowledgeandskills. The incorporation of new systems and materials bring a lot of concerns regarding system implementation, capabilities and mechanical proper- ties of the different materials. One of the biggest problems that still re- main in CAD/CAM dental systems is theaccuracyofeachstepintheCAD/ CAM chain, from digital impression to the milling step. Using computer aided manufacturing is dependent on the calibration of hardware with software in the workflow. Further- more, the virtual configuration of the die spacer between the tooth and the restorations is essential for the accuracy of the marginal adapta- tion and has to be calibrated for each one of the systems. Weittstein et al. demonstrated that the difference of fit between CAD/ CAM restorations is directly related to the gap param- eters from the computer design and also related to the intrinsic proper- tiesoftheCAD/CAMsystem.[16] Conclusion This review of current and past lit- erature regarding the evolution, characteristics, and marginal fit of milled CAD/CAM all-ceramic resto- rations materials and systems show thatitispossibletofabricaterestora- tions with the same marginal fit ex- pected from conventional methods and within the range of clinically ac- cepted restorations. When compar- ing both methods the advantage of using CAD/CAM technology is not toobtainthemostpreciseleveloffit, butrathertoobtainahighlevelofre- liability in a large number of restora- tions; especially when high produc- tion levels are expected. However, therearealimitednumberofclinical studies and the diversity of the re- sultsbetweensystemsandprotocols does not allow us to give a definitive conclusion. 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CADSystem Manufacturer Fileoutput 3Shape 3Shape Propietary/STL ARTI/Modelliere Zirkonzahn STL CeraMill AmannGirrbach STL CerconEye/Art Dentsply Propietary CEREC SironaDentsply Propietary Delcam Delcam STL DentalWings DentalWings STL PlanCAD Planmeca STL Exocad Exocad STL InLab SironaDentsply Propietary Procera NobelBiocare Propietary/STL Table2:Most populardentalCADsystemsavailablefor2015. CAMSystem Manufacturer Type Millingmaterials BruxZirMill Glidewell Dry Zirconia,wax,PMMA CeraMillMotion AmannGirrbach Wet/dry Zirconia,Glassceramic,ceramicresins,LithiumDisilicate, ChromeCobalt,PMMA,wax,titanium DatronD5 Datron Wet/dry Zirconia,Glassceramic,ceramicresins,LithiumDisilicate, ChromeCobalt,PMMA,wax,titanium Denzir Ivoclar Dry Zirconia PlanMill Planmeca Wet Lithiumdisilicate,ceramicresin InLabMCXL Sirona Wet/dry Zirconia,Glassceramic,ceramicresins,LithiumDisilicate, ChromeCobalt,PMMA,wax,titanium LAVA 3MESPE Dry Zirconia,wax,glassceramic M1/M5 Zirkonzahn Wet/dry Zirconia,Glassceramic,ceramicresins,LithiumDisilicate, ChromeCobalt,PMMA,wax,titanium Procera NobelBiocare Wet Aluminumoxide Zenotec Ivoclar Dry Zirconia,wax,PMMA Table3:Most populardentalCAMsystemsavailablefor2015. Dr Christian Brenes, DDS. Master in Prosthodon- tics. Clinical Assistant Professor Dental Col- legeofGeorgiaat Augusta Dr Ibrahim Duqum, DDS. MS. Clinical As- sistant Professor. Department of Prostho- dontics at the University of North Caro- linaat ChapelHill. Dr Gustavo Mendonza, DDS. MS. PhD. Clinical Associate Professor. Department of Biologic and Materials Sciences, Di- vision of Prosthodontics, University of MichiganSchoolofDentistry. University. International speaker for Digi- tal Dentistry Education and BlueSkybio Academy on guided surgery, clinical digi- talprotocolsanddentalaesthetics. Hecanbecontactedat: christian@blueskybio.academy