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ePaper created 2016-10-04, 09:33:57 | version 1.38.0
CAD/CAM material and systems literature review | 13 CAD/CAM 3 2016 Fig. 4: Full arch implant supported prosthesis milled from a partially sintered sintered (green state) zirconia puck. Fig. 5: STL file of an intraoral scan. Girbach), Prettau (Zirkonzahn), Cercon (DENTSPLY), BruxZir (Glidewell Laboratories), IPS ZirCAD (Ivoclar Vivadent), Zenostar (Ivoclar Vivadent), inCoris ZI (Sirona Dental), VITA In-Ceram YZ (Vident), among others.Companieshaveintroducedmaterialsthatare incombinationwithzirconiatoimproveitsproperties indifferentclinicalsituations.LavaPlus,forexample, is a combination of zirconia and a nano-ceramic. CAD/CAM systems A number of different manufacturers are providing CAD/CAMsystemsthatgenerallyconsistofascanner, designcomputerandamillingmachineor3-Dprinter. Laboratoriesareabletoreceivedigitalimpressionfiles fromdentistsoruseascannertocreatedigitalmodels thatareusedforrestorationsdesigningorCAD.Dental scannersvaryinspeedandaccuracy.Millingmachines vary in size, speed, axes, and also in which restorative materials can be milled; in this category milling ma- chines could be classified as wet or dry depending if the materials require irrigation. The development of dental CAD/CAM systems oc- curred around 1980 with the introduction of the Sopha system developed by Dr Duret. A few years afterthatevent,DrMormannandtheelectricalengi- neer Marco Brandestini developed the CEREC-1 sys- temin1983,thefirstfulldigitaldentalsystemcreated to allow dentists to design and fabricate in-office restorations. Since then, the continuous evolution of systemsdedicatedtothisfieldhascontinuedandhas exponentially increased in the last decade.14 CEREC systems has evolved into CEREC Bluecam scan- ner;accuraciesascloseas17micronsforasingletooth have been reported by authors using this system. RecentlyCERECOmnicamwasintroducedofferingtrue colour digital impressions without the need of a con- trastmedium.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 percent of the specimens had a vertical gap measurement with less or at least 75 microns.15 TheCERECInLabCADsoftware(SironaDental)wasde- signedfordentallaboratoriesforawiderangeofden- 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) scanner and design the restoration; once this process is completed, the file 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 first systemtoprovidefabricationofarestorationusinga network connection. According to research data the average ranges of marginal fit of this restorations are from 54 to 64 microns.20 A computer integrated crownreconstructionsystem(CICERO)introducedby Denison et al. in 1999 included a rapid custom fabri- cation of high-strength alumina coping and semi- finishedcrownstobedeliveredtodentallaboratories for porcelain layering and finishing.15 Another system that was developed years ago was the Celay system, which fabricated feldpathic resto- rations through a copy-milling process. The system duplicated an acrylic resin pattern replica of a resto- ration. Zirkonzahn developed a similar system called the Zirkograph in 2003, which was able to copy-mill zirconiaprosthesisandrestorationsoutofareplicaof the restoration. Some years after, the Cercon system (DENTSPLY Ceramco) was able to design and mill zirconia restorations out of a wax pattern.1 Almostatthesametimethatthesecompaniesdevel- oped the first copy mill prototypes, Lava (3M ESPE) introduced in 2002 the fabrication of yttria-tetrago- nalzirconiapolycrystal(Y-TZP)coresandframeworks forallceramicrestorations.WiththeLavasystem,the dieisscannedbyanopticalprocess,theCADsoftware Fig. 4 Fig. 5 32016