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Dental Tribune Middle East & Africa Edition | 3/2018 LAB TRIBUNE ◊Page B2 CAD System 3Shape ARTI / Modelliere CeraMill Cercon Eye/Art CEREC Delcam Dental Wings PlanCAD Exocad InLab Procera Manufacturer 3Shape Zirkonzahn Amann Girrbach Dentsply Sirona Dentsply Delcam Dental Wings Planmeca Exocad Sirona Dentsply Nobel Biocare File output Propietary/STL STL STL Propietary Propietary STL STL STL STL Propietary Propietary/STL Table 2: Most popular dental CAD systems available for 2015. design computer and a milling ma- chine or 3-D printer. Laboratories are able to receive digital impression fi les from dentists or use a scanner to 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 classifi ed 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- trical engineer Marco Brandestini de- veloped the CEREC-1 system in 1983, the fi rst full digital dental system cre- ated to allow dentists to design and fabricate in-offi ce restorations. Since then, the continuous evolution of systems dedicated to this fi eld has continued and has exponentially in- creased in the last decade.14 CEREC systems has evolved into CEREC Bluecam scanner;accuracies as close as 17 microns for a single tooth have been reported by authors using this system. Recently CEREC Omnicam was introduced offering true colour digital impressions with- out the need of a contrast medium. In a recent study by Neves et al. (2013) on the marginal fi t of CAD/CAM restorations fabricated with CEREC Bluecam, they compared lithium disilicate single unit restorations to heat-pressed restorations and 83.8 percent of the specimens had a verti- cal gap measurement with less or at least 75 microns.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 this process is completed, the fi le can be sent to a remote milling machine or a milling centre for fabrication in a wide range of materials. The Procera system, introduced in 1994, was the fi rst system to provide fabrication of a restoration using a network connection. According to research data the average ranges of marginal fi t of this restorations are from 54 to 64 microns.20 A computer integrated crown reconstruction sys- tem (CICERO) introduced by Denison et al. in 1999 included a rapid custom fabrication of high-strength alumina coping and semifi nished crowns to be delivered to dental laboratories for porcelain layering and fi nishing.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 out of a wax pattern.1 Almost at the same time that these companies developed the fi rst 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 fi t that can be as low as 21 microns.27 Some other systems that were able to mill zirconia were DCS Zirkon(DCS Den- tal) and Denzir.16 In the last decade, companies have decided to differentiate their products by having a full CAD/CAM platform or by focusing on specifi c areas of expertise like CAD software and intraoral scanners; these compa- nies claim to be open platform because their systems allow to export universal fi les such as STL or OBJ (Fig. 5) to be used with the majority of nest- ing softwares and milling machines that are able to import them. Defenders of closed plat- forms claim that the inte- gration of different CAD/ CAM systems does not allow for a good integration between parts and probably leads to the incorporation of fabrication errors; at this point no research about systems integra- tion is available. Table II shows some of the systems used for dental CAD with their fi le output; Table III shows some of the most used CAM systems with their material recommenda- tions and capabilities. Some of the main concerns from cli- nicians about all-ceramic CAD/CAM restorations accuracy of fi t are: scan- ning resolution, software designing limitations, and milling hardware limitations of accuracy. Clinicians’ and technicians’ experience with the CAM/CAM system integration is also a key factor for fabricating good res- toration; the computer software per se will not allow an inexperienced operator to create an excellent den- tal restoration from scratch.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 fi t of CAD/CAM restorations is com- pared to conventional restorations the fabrication of dental restorations is still a complex task that requires experience, knowledge and skills. 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 the accuracy of each step in the CAD/ CAM chain, from digital impression to the milling step. Using computer aided manufacturing is dependent on the calibration of hardware with software in the workfl ow. Further- more, the virtual confi guration 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 fi t between CAD/ CAM restorations is directly related to the gap param- eters from the computer design and also related to the intrinsic proper- ties of the CAD/CAM system.16 Conclusion This review of current and past lit- erature regarding the evolution, characteristics, and marginal fi t of milled CAD/CAM all-ceramic resto- rations materials and systems show that it is possible to fabricate restora- tions with the same marginal fi t 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 to obtain the most precise level of fi t, but rather to obtain a high level of re- liability in a large number of restora- tions; especially when high produc- tion levels are expected. However, there are a limited number of clinical studies and the diversity of the re- sults between systems and protocols does not allow us to give a defi nitive conclusion. References 1. Miyazaki T, Hotta Y, Kunii J, Kuriy- ama S, Tamaki Y. A review of dental CAD/CAM: current status and future perspectives from 20 years of expe- rience. Dent Mat Journal 2009. 28: 44–56. 2. Fasbinder DJ. Restorative material options for CAD/CAM restorations. Compend Contin Educ Dent. 2002. 3. Pallesen U, van Dijken JW. An 8-year evaluation of sintered ceram- ic and glass ceramic inlays processed by the Cerec CAD/ CAM system. Eur J Oral Sci. 2000. 4. Kelly JR, Denry IL. Stabilized zirco- nia as a structural ceramic: an over- view. Dent Mater 2008. 24:289–98. 5. Kelly, R. Nishimura, I. Campbell, S. Ceramics in dentistry: Historical roots and current perspectives. Jour- nal of Prosthetic Dent. 1996. 6. Tinschert J, Zwez D, Marx R, Anusavice KJ. Structural reliability of alumina, feldspar, leucite and zir- conia based ceramics. J Dent 2000. 28:529–535 7. Luthardt RG, Sandkuhl O, Reitz B. Zirconia- TZP and alumina advanced technologies for the manufacturing of single crowns. Eur J Prosthodont Restor Dent. 1999. 8. Kurbad A, Reichel K. Multicolored ceramic blocks as an esthetic solu- tion for anterior restorations. Int J Comput Dent. 2006. 9. Bindl A, Mormann WH. Survival rate of mono-ceramic and ceramic- core CAD/ CAM-generated anterior crowns over 2–5 years. Eur J Oral Sci. 2004. 10. Esquivel-Upshaw JF, Chai J, Sansa- no S, Shonberg D. Resistance to stain- ing, fl exural strength, and chemical solubility of core porcelains for all- CAM System BruxZir Mill CeraMill Motion Datron D5 Denzir PlanMill InLab MC XL LAVA M1/M5 Procera Zenotec Manufacturer Glidewell Amann Girrbach Datron Ivoclar Planmeca Sirona 3M ESPE Zirkonzahn Nobel Biocare Ivoclar Type Dry Wet/dry Wet/dry Dry Wet Wet/dry Dry Wet/dry Wet Dry Milling materials Zirconia, wax, PMMA Zirconia, Glass ceramic, ceramic resins, Lithium Disilicate, Chrome Cobalt, PMMA, wax, titanium Zirconia, Glass ceramic, ceramic resins, Lithium Disilicate, Chrome Cobalt, PMMA, wax, titanium Zirconia Lithium disilicate, ceramic resin Zirconia, Glass ceramic, ceramic resins, Lithium Disilicate, Chrome Cobalt, PMMA, wax, titanium Zirconia, wax, glass ceramic Zirconia, Glass ceramic, ceramic resins, Lithium Disilicate, Chrome Cobalt, PMMA, wax, titanium Aluminum oxide Zirconia, wax, PMMA Table 3: Most popular dental CAM systems available for 2015. B3 ceramic crowns. Int J Prosthodont. 2001. 11. Reich SM, Peltz I, Wichmann M, Es- tafan D. A comparative study of two CEREC software systems in evaluat- ing manufacturing time and accu- racy of restorations. Gen Dent. 2005 12. Anusavice, K. Phillips’ Science of Dental Materials. 12 edition. In: Saun- ders. Elsevier; 2014. 13. Kosmac T, Oblak C, Jevnikar P, Funduk N, Marion L. The effect of surface grinding and sandblasting on fl exural strength and reliability of Y-TZP zirconia ceramic. Dent Mater. 1999 14. Raigrodski AJ. Contemporary all- ceramic fi xed partial dentures: a re- view. Dent Clin North Am. 2004. 15. Neves F, Prado C, Prudente M, Car- neiro T, Zancope K, Davi L, Mendonçe G, Cooper L, Soares C. Marginal fi t evaluation with micro CT of lithium disilicate crowns fabricated by chair- side CAD/CAM systems and the heat-pressing technique. J Prosthet Dent. 2014. 16. Hertlein G. Kramer M, Sprengart T, et al. Milling time vs marginal fi t of CAD/CAM manufactured zirconia restorations. J. Dent Res 2003. 82:194. 17. Guazzato M, Proos K, Quach L, Swain MV. Strength reliability and mode of fracture of bilayered porce- lain/zirconia (Y-TZP) dental ceramics. Biomaterials. 2004. 18. Syrek, A. Reich, G. Ranftl, D., Klein, C. Cerny, B. Brodesser, J. (2010). Clini- cal evaluation of all-ceramic crowns fabricated from intraoral digital im- pressions based on the principle of active wavefront sampling. Journal of Dentistry. 2010. 19. De Vico G, Ottria L, Bollero P, Boni- no M, Cialone M, Barlattani A Jr. et al. Aesthetic and functionality in fi xed prosthodontic: experimental and clinical analysis of the CAD–CAM systematic 3Shape. Oral Implantol. 2008; 1:104–115. 20. Gehrt, M. Wolfart, S. Rafai, N., Reich, S. Edelhoff, D. (2013). Clinical results of lithium-disilicate crowns after up to 9 years of service. Clinical Oral Investigations. 17(1), 275–84. 21. Gupta TK, Bechtold JH, Kuznickie RC, Cadoff LH, Rossing BR. Stabili- zation of tetragonal phase in poly- crystalline zirconia. J Mater Sci 1978;13:1464. 22. Piconi C, Maccauro G. Zirconia as a ceramic biomaterial. Biomaterials. 1999; 20:1–25. This article was published in CAD/ CAM international magazine of digi- tal dentistry No. 03/2016. Dr Christian Brenes, DDS. Master in Prosthodon- tics. Clinical Assistant Professor Dental Col- lege of Georgia at Augusta University. International speaker for Digi- tal Dentistry Education and BlueSkybio Academy on guided surgery, clinical digi- tal protocols and dental aesthetics. He can be contacted at: christian@blueskybio.academy Dr Ibrahim Duqum, DDS. MS. Clinical As- sistant Professor. Department of Prostho- dontics at the University of North Caro- lina at Chapel Hill. Dr Gustavo Mendonza, DDS. MS. PhD. Clinical Associate Professor. Department of Biologic and Materials Sciences, Di- vision of Prosthodontics, University of Michigan School of Dentistry.