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Journal of Dentistry and Oral Care
Review Article Open Access
1Specialist Prosthodontist, Private dental practice, Dubai2Senior Lecturer, Department of Prosthodontics, Bangalore Institute of Dental Sciences, Bangalore
Abstract
CAD/CAMisafieldofdentistryandprosthodonticsusingCAD/CAM(com-puter-aided design and computer-aided manufacturing) to improve the design and creationofdentalrestorations,especiallydentalprostheses,includingcrowns,crown,veneers,inlaysandonlays,fixedbridges,dentalimplantrestorations,dentures(remov-ableorfixed),andorthodonticappliances.ThereexistsamisconceptionthattheCAD/CAMprocessiscomplicatedandtime-con-suming.However,theCAD/CAMsystemissimpletooperate,versatile,andprecise.All-ceramicrestorationscanbedesignedandmilledchairside,withtheaddedadvan-tage of elimination of traditional impressions and temporaries, and the patient leaves theappointmentinaboutanhourwiththefinalrestorationinplace.DentalCAD/CAMis approaching20yearsof clinical experienceandhas aproven track recordonallrelevant aspects of clinical performance, including fit, longevity and survival rates,sensitivity,strength,andwear.
*Corresponding author: Smitha Annie Jacob, Specialist Prosthodontist, Private dental practice, DubaiE-mail: [email protected]
Keywords:CADCAM;Ceramics;DigitalDentistry;DigitalWorkflow;CEREC
Citation:SmithaA.J.,etal.CADCAM- Understanding the Basics: A Review.(2016)JDentOralCare2(2):50-55.
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Aim TheapplicationofdentalCAD/CAMsystemsispromising,notonlyinthefieldofcrownsandFPDs,butalsoinotherfieldsofdentistry.ThereisnodoubtthattheapplicationofCAD/CAMtechnologyindentistryprovidesinnovative,state-of-artdentalservice,andcontributestothehealthandQualityofLiving(QOL)ofpatients.Thepurposeofthispaperistogiveanin-depthknowledgeofCADCAMtechnologytothereadersastoday’sdentistryhasenteredintothedigitalera.
Introduction
ThetermCAD/CAM,whichcomesfrommachine-tool technologyandstandsfor“Computer-Aided-Design/Comput-er-Aided-Manufacturing”,designatesthethree-dimensionalplanningofaworkpieceonthescreenofacomputerwithsubsequentautomatedproductionbyacomputercontrolledmachinetool[1,2].In1971,FrancoisDuretintroducedCAD-CAMtechnologytothefieldofdentistry.Hisideawasbasedupontheassumptionthatthetechnologiesestablishedinindustrycouldbeeasilytransferredtodentistry. Thoughcastingprocedurehasadvancedoverthepastyears,eachofitsstepscouldinduceerrorinthefinalcasting.Until1988,indirectceramicdentalrestorationswerefabricatedbyconventionalmethods(sintering,castingandpressing)andneitherwaspore-free.Machiningblocksofpore-freeindustrialqualityceramiccanalternatelyproducepore-freerestorations[3-5].Thetre-mendousadvancesincomputersandroboticscouldalsobeappliedtorevolutionizedentistryandprovidebothprecisionandreducetimeconsumption.With thecombinationofoptoelectronics,computer techniquesandsinter technology,computerizeddentistry
CAD CAM - Understanding the Basics: A Review
Copyrights: ©2016SmithaA.J.ThisisanOpenaccessarticledistributedunderthetermsofCreativeCommonsAttribution4.0InternationalLicense.
50
Smitha Annie Jacob1*, Savitha P.N2
Received date: August 10, 2016Accepted date: August 29, 2016 Published date: September 02, 2016
SmithaA.J.,etal.
DOI: 10.15436/2379-1705.16.1046
haspavedthewayforanewgenerationdentalceramicwithanunprecedentedhighstrengthanddurability,derivedfromdevel-opmentsinNano-ceramictechnologiesinthelastdecades.
What is CAD CAM?ThecontemporaryCAD/CAMsystemsconsistofthreecompo-nents: 1.Thescanner,whichscansthedentalpreparationpro-videdbythedentisteitherintra-orallyorextra-orallybyrefer-ence to toothmodels (Figure 1). For inlays and single crownframeworks,justthesurfacedataofthepreparedteethneedtobedigitized.ForFPDframeworksoradditionalocclusalcharacter-ization, further data from the neighboring teeth and antagonists, aswellasfromthespatialrelationofthepreparedteethtooneanother,arerequired[6-9].
Figure 1:CERECScanner.
2.ThesoftwareCADconsistsofacomputerunitusedfor the three-dimensional planning and design of restorations on thecomputerscreen(Figure2).Thesoftwareprogramsavailabletodayoffer a high level of intervention andpermit thedesignandproductionofanindividuallyadaptedrestoration.SystemsnotofferingafullCADcomponentarenotconsideredasCAD/CAMsystemsbutjustasCAMsystems[10].
Figure 2 : Softwaredentaldesigner.
3. The hardware CAM covers different productiontechnologies for converting the virtual restoration into a den-talmaterial(Figure3).Atpresent,computer-controlledmillingorgrindingmachinesaremainlyused.Theymachinetheresto-ration from the fullmaterial block consistingof prefabricatedmetal or ceramic[11,12].Asarule,aftertheCAMproduction,somemanual corrections and final polishing or individualization ofthe restorationwith staining colors or veneeringmaterials arerequiredtobecarriedoutbythedentaltechnician(Figure4).
Figure 3 :SironaMillingUnit.
Figure 4 :CycleofCAD/CAM.
Scanning of Preparation Since1971,anumberofattemptstodentalCAD/CAMhavebeenreported.Themostprominentare
1. Holodontography by altschuler : Areportdated1971claimsthatdevelopmentoflaserholographycansignificantlyinfluencetheproceduresusedindentalcare.Itmentionstheuseoftoothprints recorded bymeans of a combination of computers andlaser holography. Such tooth print could serve for diagnosticand forensic purposes, but also applicable to prosthetic and re-storativework[13].Aspecifictaskwouldbecomputer-controlledmillingofdentalcrownsbasedoncontourholograms.
2. The Duret/ Hennson/ Sopha system :TheoriginofFrench
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approachdatesbacktotheearlyseventies.Goalofthisendeav-oristhecomputer-aidedrestorationanddentistryinthebroad-estsense.Theprimaryapplicationofthesystem,however,wasthefabricationofcrowns.Theoriginalscanningprinciplewasbasedonlaserholography.DrFrançoisDuret’smethodrequiresasetofdifferentviewsofthepreparation.Theindividualviewsarecorrelatedbythecomputertoproduceathree-dimensionalrecord.Tofacilitatethealignment,thedentistplacesreferencebracketswithin thefield of view.Thedesign is accomplishedbymanually tracing thecervicalmarginof thepreparationbymeans of a large screen color monitor and a digitizing tablet[14].Theprogramusesaselectiveshrinkagealgorithmtoproduceanoptimumcementationgap.Themachineisequippedwiththreeaxesandhastheadditionalcapabilitytoturntheworkpieceup-sidedown.
3. Active triangulation:Thisprincipledoesnotrelyonanim-agepairasobtainedbytwo-eyedvision.Insteadoneopticalpathisconvertedfromreceptortotransmitteror,moreaccurately,apatternprojector.Duetothephysicalseparationofthetwochan-nelsacertainamountofparallaxisintroduced.Sincetheparal-laxisaknownconstant,theresultingrange-dependentshiftofthepatternprojectedontotheobjectcanbeaccuratelyconvertedinto depth values[15].
Data Acquisition Thefirstelementofthedataacquisitionchainisasolidstateimagesensor.Thisdeviceaccuratelyconvertslightinten-sitytovoltagewhenreadinalinebylinemode.Thealternatingregionsofdarkandlighttranslateintohigherandlowervoltag-es.Whenreadingasensorline,whichrunsmesio-distally,sinu-soidal pattern is observed[16,17].Whilethereticlefeaturesasquarepattern (bands are either transparent or totally opaque), limit-edresolutionofthedetectedsignalapproximatesasinewave.Justliketheindividualline,everylineofthepatternisshiftedproportionallytoverticaldistances.Inmathematicalterms,thephaseofthespatialfrequencyismodulated. Oncetheparticularphasewhichcorrespondstoaref-erencelevelhasbeenestablishedbycalibration,theelevationofanypointoftheobjectcanbecalculatedfromthephaseshift.Amorecarefulanalysisofthesinusoidalpatternrevealssomeadditionaldifficulties:theshapeofthispatternisnotverywellbehaved.Itexhibitslargelocalvariationsinbothamplitudeandoffseti.e.thedistancefromthebaseline.Thelatterarecausedbythevariousamountsofstraylightandsensordarkcurrent.Theformerarecausedbythefact,thattheamountoflightpickedupbythesensorisafunctionoftheslopeofthepreparationwallsat any point.An additional difficulty arises from the non-uni-formityintheresponseoftheindividualsensorelements.Duetolimitationsintheartofsemiconductorfabrication,atypicalsensorwillevencontainacertainamountofblindcells.Inordertoisolatethethreevariables–phase,magnitudeandoffset-atleast three images are required, all takenwith the exact sameorientation,buteachusingadifferentphaseoftheprojectedpat-tern[18,19]. Asequenceoffourimages(Figure5),provedtobeamoreefficientapproachinourparticularapplicationandhard-wareimplementation.Thereticleisphysicallytranslatedduringaperiodof4times40millisecondsfromanarbitrary0˚initialpositionover 360˚, i.e., one entire line period.For reasonsofclarity, the illustration shows a fixed position for each frame,
whileinrealitythepatterniscontinuouslysweptacrosstheim-age. Various levels of intensity, reflecting the actual positionofpattern,aredetected.Thesignalisasteppedapproximationof theactual intensitypatternsince theelementsof thesensorhave finite dimensions (period of pattern 200µ divided into a22µelementpitchofthesensorarrayyieldsapprox.9samplesperperiod),whilethemodulatedpartofthesignalisshiftedinphase,theoffset,representedbytheaverageintensity,remainsconstant[20,21].Thisobservationsuggestsadifferentialoperation.Subtractingthe180˚imagefromthe0˚imagecancelstheoffsetportion off the signal. Since this subtraction is achieved by areactionofmodify-writeoperation in the imagememory, it isexecutedinstantaneously.The90˚-270˚subtractionisaccom-plishedinthesameway.
Figure 5:Sequenceoffourimages.
At the endof the 160millisecond exposure,we thusfindthetwodifferentialdatasetsintheframebuffer.Thechar-acterizationfeaturesofthemodulationhavebeenunaffectedbythe subtraction, the amplitudes have been doubled and the sig-nalsarenowbiasedatthezerolevel.The90˚phasebetweenthetwosignalshasbeenpreserved.Wearenowleftwithadatapaircorrespondingtoeachpicturecell-orpixel-oftheimage.Datapairsmustbetransformedtoyieldthedesireddepthinformation.Thetwo-dimensionalarrayofthedepthvaluesisreferredtoastheprofile.A second setofvalues, representing local contrastamplitudecanbeobtainedfromthisconversion;inourcontextwecallthissecondsetofdatathehill-shadedimage[22-24]. Priortomakinganopticalimpressionwiththesensor,it isnecessary topowder the toothsurfaceandtheentirefielduniformly.Thedetectionof thepattern cast onto anuntreatedpreparationisnotpossibleforthefollowingreasons:ontheonehandthedifferentslopesofthepreparationandthedifferencesinsurfacequalityyieldadynamicrangeofintensities,whichistoolargetobeaccommodatedbythesensorandtheassociated
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circuitry.Thesteepwallsappearasvirtuallyblackregions.Thecuspwhichreflecttheincidentlightinaspecularfashiontendtoglaretherebycausingsmearingartifactssimilartothehumanretinawhenwelookdirectly intoapowerful lightsource[25,26].Ontheotherhandthedentinandenamelistranslucentwherebyit absorbs at least partially, the pattern projected onto its sur-face.Toalleviatebothproblems,thesurfaceofthetooth,andforthatmatter,theentirefieldofviewmustbecoatedwithathinopaquerlayer.Afinecoatoftitaniumdioxideproducesahighlyuniformscatteringofthelight.Theremainingvariationininten-sity is verydesirable since it enhances the three-dimensionalfeaturesofthepreparation.
Milling of the Ceramic Restoration Therestorationismilled(4-7minutes)withadiamondwheelfromapremanufacturedandstandardizedceramicblockinthemillingchamberoftheCAMunit.Factorystandardized,preformeddentalporcelainblocksarehomogenousandalmostpore-free(VitaCerecblocks,DicorCerecblocks).
The Cam UnitApumpsystemwithanattachedwaterreservoirlocatedatthebaseofthemobilecartmaintainsthewaterpressurerequiredfor thehydraulicdrivenwater turbine in themillingchamber.Duringmillingabout5litersofwateriscycledinternally,whicheliminatestheneedforexternalwatersupplyanddrainage.Thewater reservoirsystemalsocontainsamicroporousfilter thattrapsanyofthelooseneddiamondparticlesseparatedfromthewheelforfutureretrieval[27,28](Figure6).
Figure 6:Themillingunit.
Procedure[29,30]: •Theappropriateceramicblockisselectedfromase-riesconsistingofdifferentsizesandshade •Theceramicblockismountedonametalstub(retain-er), inserted into the milling unit and the grinding operation is initiated. •Grindingoftheceramicrestorationisdonebyadia-mond–coateddisk/wheelinconjunctionwithahighvelocitywater-spray,whichsimultaneouslycoolsandcleansthemillingdisk.Therestorationismilledfromthemesialtothedistalprox-imalsurfaceswiththeblockrotatingalongitscentralaxisandbeingsteadilyadvancedforwardduringthemillingprocess.Inaddition,thediamondwheelnotonlyrotatesbutalsotranslates
upanddownovertheporcelainblockbeingmilled.Aseriesofstepsorcuts(200–400)arerequiredformillingaceramicres-toration.
The Computer program associated with the milling process has additional interesting features such as[31]: • Before themilling process, the screen displays thedimensionsoftherestorationfromoneproximalsurfacetotheotherin1/900thofanmm. •Duringthemillingoperation,thescreencontinuouslyinformstheoperatorofthepercentageofcompletion. • A continuous readout is displayed concerning thecuttingefficiencyofthediamondwheel,therebyindicatingtheprobableneedforreplacement.
Advantages of CAD CAM[32-35]
1.Theconceptthatadentistcan,inasingleappointment,admin-isteranestheticinpreparationfor,preparethetoothfor,makeanimpression for, design, mill, customize and place a restoration isdesirableformanycliniciansandpatients.Thecommandof“one-appointment”dentistryispowerfulnotonlyforthepatient,butalsofortheentiredentalteamandtheoffice’sproductivity.Single-appointmentdentistryhasavarietyofbenefits:theneedforonlyoneadministrationofanesthetic,theabsenceofneedfortemporaryorprovisionalrestorations(therefore,nolosttempo-rariesorre-cementations),theabsenceoflaboratoryfeesandareductioninsecond-chairset-upcosts.Thesefactorsultimatelyequatetofewerinstrumentsneedingtobesterilized, lessneedforchairtimeset-up/breakdownandimprovedofficeefficiency. 2.Another, oftenoverlookedadvantage is thedisposable sup-plies that can be eliminated (from impression material, wax,stone, temporarybridge resin andcement to cottonandpaperdisposables)by institutionofaCAD/CAMsystem.Clinicianscangainotherintangibleadvantagesinthelongtermbyintro-ducing CAD/CAM technology into their already-busy dentalpractices.WithCAD/CAMtechnology,cliniciansmaintaintotalproduct and artistic control of the restorations to be fabricated and seated. It allows clinicians to spend themajority of theirtimeontoothpreparationandonseatingofthefinalrestoration;thesoftwareprograms’optionsdeliveraproductthatmayneedonlyendpointcharacterization,stainingorglazing.Thecomput-er and milling processes diminish potential inaccuracies result-ingfromthehand/laboratoryfabricationprocessandareabletoprovide a restoration that fitswithin the 50-micrometer rangeestablishedbytheAmericanDentalAssociation.
3.When thedentist implementsCAD/CAMtechnology,heorshe must create a schedule that supports single-appointment treatment.This schedule arrangement can both save time andincrease efficiency. Dentists can complete most CEREC sin-gle-unitcrownswithinoneandone-halfhours.Dentistscantreatquadrantswithintwoortwoandone-halfhours.Withthistypeofdentistry,thesecond“seating”appointmentnowisfreedupand can be re-designated for an additional productive appoint-ment.Givenatraditionaltwo-appointmentprocedureandtimeallotment, this single-appointment treatment approach becomes practical.Moreover, a practitioner seasoned in using CERECcanperformadditionalprocedureswhiletherestorationisbeingmilled,againenhancingthepractice’sefficiencyandproductiv-ity.
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4. Patients often experience irritation in, sensitivity in and/ordifficultyincleaningtemporizedteeth.Single-appointmentden-tistryavoidsthesecomplaints.Also,cliniciansmustconsiderthediminished chance of bacterial invasion during this phase; de-creasedpulpalstressresultingfromexcessivecleaning,dryingor trauma; and decreased need for the additional tooth manipu-lationthatoftenisexperiencedatasecondappointment.Giventhe fact that veneers represent a significant portion of labora-tory-fabricated restorations today and that veneer temporarieseasily can be displaced and are time-consuming to fabricate,dentistsshouldfindtheconvenienceofsingle-appointmentden-tistrysignificant.
5. Furthermore, theCEREC veneer software program is easytouseandwillenhance the implementationofsingle-appoint-ment dentistry.Dentists have the ability to include their teammembersbydelegatingsomeofthetasksintheCERECprocess.In sucha scenario, assistantsmaybe included in introductoryCERECtrainingandcanbettertheirskillsbytakingadditionaltrainingcoursesspecificallydesignedforassistants.Inpractice,the team approach flows thus: the dentist prepares the tooth,powdersitandmakestheopticalimpression.Thentheassistantdesigns the restoration, mills it, polishes it and prepares it for bonding.Finally,thedentistcompletestheprocedurebybond-ingtherestoration.
Disadvantages of CAD CAM[36-38]
Intheimplementationofanynewtechnology,discus-sions arise that require critical thinking. The primary consid-eration in a CAD/CAM purchase is the length of the learning curve,whichmayrangefromafewdaystoseveralmonthsandmay result in the lossofofficeproduction, the lossofpatienttreatmenttimeandanincreaseintheclinician’sfrustration.Oth-er obstacles to incorporating this system into practice are thecostof the equipment, thepotential for thedental team to re-sist the system’s use, the clinician’s lack of confidence in us-ingacomputerizedsystem,andperhapstheclinician’slackofwillingnesstolearnanewconceptthatwillrequiretrainingandpractice.Dentistswhohavedifficulty integrating this technol-ogyintotheirpracticesusuallyaredentistswhodonotwanttochangethewaytheyarepracticing. However,theadvantagesofthissystemoutweighthesedisadvantages listed and so it is emerging as a successful treat-mentoption.
Summary During the past decade, computer-aided design/ manu-facturing(CAD/CAM),whicharewell-knownprocessesintheindustrialworld,havefoundtheirwayintodentistry.Interestinthis designing and manufacturing process occurred because of itspotentialasanalternativetothelost-waxtechniquethathasbeenusedformanydecadesforfabricatingdentalrestorations.Anumber of reports in the literature[39-42]inrecentyearsdetailtheCAD/CAMmethods thathavebeenused indentistry.Equallyimpressive is the number of articles reporting on the clinical suc-cess and the improved characteristics of restorations fabricated bytheseCAD/CAMmethods.
References
1.Fairhurst,C.W.Dentalceramics:Thestateofthescience.(1992)AdvDentRes6:78-81.2.Giordano,R.,Cima,M., Pober,R.Effect of surface finish on theflexuralstrengthoffeldspathicandaluminousdentalceramic. (1995)IntJProsthodont8(4):311-319.3.Rinke,S.,Hüls,A.Copy-milledaluminouscoreceramiccrowns:Aclinicalreport.(1996)JProsthetDent76(4):343-346.4.Thompson,J.Y.,Bayne,S.C.,Heymann,H.O.Mechanicalpropertiesofanewmica-basedmachinableglassceramicforCAD/CAMresto-rations.(1996)JProsthetDent76(6):619-623.5.Heymann,H.O.,Bayne,S.C.,Sturdevant, J.R., et al. Theclinicalperformance of CAD-CAM-generated ceramic inlays: A four yearstudy.(1996)JAmDentAssoc127(8):1171-1181.6.Chai,J.,McGivney,G.P.,Munoz,C.A.,etal.Amulticenter longi-tudinalclinicaltrialofanewsystemforrestoration.(1997)JProsthetDent77(1):1-11.7.Odén,A.,Andersson,M.,Magnusson,D., et al.FiveyearclinicalevaluationofProceraAllCeramcrowns.(1998)JProsthetDent80(4):450-506.8.Willer, J.,Rossbach,A.,Weber,H.P.Computer-assistedmillingofdental restorations using a newCAD/CAM data acquisition system.(1998)JProsthetDent80(3):346-353.9.May,K.B.,Russell,M.M.,Razzoog,M.E.,etal.Precisionoffit:TheProceraAllCeramcrown.(1998)JProsthetDent80(4):394-404.10.Sellen,P.N.,Jagger,D.C.,Harrison,A.Computer-generatedstudyofthecorrelationbetweentooth,face,archforms,andpalatalcontour.(1998)JProsthetDent80(2):163-168.11.Sindel,J.,Frankenberger,R.,Krämer,N.,etal.CrackformationofAll-Ceramic crowns dependant on different core build-up and lutingmaterials.(1999)JDent27(3):175-181.12.Burke,F.J.Maximizingthefractureresistanceofdentine-bondedall-ceramiccrowns.(1999)JDent27(3):169-173.13.Chen,H.Y.,Hickel,R.,Setcos, J.C., et al.Effectsof surfacefin-ish and fatigue testing on the fracture strength of CAD-CAM and pressed-ceramiccrowns.(1999)JProsthetDent82(4):468-475.14.Olthoff,L.W.,VanderZel, J.M.,DeRuiter,W.J.,etal.Comput-ermodelingofocclusalsurfacesofposterior teethwith theCICEROCAD/CAMsystem.(2000)JProsthetDent84(2):154-162.15.Dahlmo,K.I.,Andersson,M.,Gellerstedt,M.,etal.Onanewmeth-odtoassesstheaccuracyofaCADprogram.(2001)IntJProsthodont14(3):276-283.16.Antonson, S.A.,Anusavice,K.J. Contrast ratio of veneering andcoreceramicsasafunctionofthickness.(2001)IntJProsthodont14(4):316-320.17.Yoshida,K.,Kamada,K.,Atsuta,M.Effectsoftwosilanecouplingagents,abondingagent,andthermalcyclingonthebondstrengthofaCAD/CAMcompositematerialcementedwithtworesinlutingagents.(2001)JProsthetDent85(2):184-189.18.Marchack,C.B.,Yamashita,T.Fabricationofadigitallyscanned,custom-shaped abutment: A clinical report. (2001) J Prosthet Dent85(2):113-115.19.VanderZel,J.M.,Vlaar,S.,DeRuiter,W.J.,etal.TheCICEROsystem for CAD/CAM fabrication of full-ceramic crowns. (2001) JProsthetDent85(3):261-267.20.Bindl,A.,Mörmann,W.H.An upto 5-year clinical evaluation ofposterior in-ceramCAD/CAMcorecrowns. (2002)IntJProsthodont15(5):451-456.21.Otto,T.,DeNisco,S.Computer-aideddirectceramicrestorations:10-yearprospectiveclinicalstudyofcerecCAD/CAMinlaysandon-lays.(2002)IntJProsthodont15(2):122-128.22.Runte,C.,Dirksen,D.,Deleré,H.,etal.Opticaldataacquisitionforcomputer-assisteddesignoffacialprosthesis.(2002)IntJProsthodont15(2):129-132.23.Addi,S.,Hedayati-Khams,A.,Poya,A., et al. Interfacegap sizeofmanually andCAD/CAM-manufactured ceramic inlays/onlays in
55
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vitro.(2002)JDent30(1):53-58.24. Cho, H.W., Dong, J.K., Jin, T.H., et al.A study on the fracturestrength of implant-supported restorations using milled ceramic abut-mentsandall-ceramiccrowns.(2002)IntJProsthodont15(1):9-13.25.Cheah,C.M.,Chua,C.K.,Tan,K.H.,etal.Integrationoflasersur-facedigitizingwithCAD/CAMtechniquesfordevelopingfacialpros-thesis.Part1:designandfabricationofprosthesisreplicas.(2003)IntJProsthodont16(4):435-441.26.Cheah,C.M.,Chua,C.K.,Tan,K.H. Integration of laser surfacedigitizingwithCAD/CAMtechniquesfordevelopingfacialprosthesis.Part2:developmentofmoldingtechniquesforcastingprostheticparts.(2003)IntJProsthodont16(5):543-548.27.Gassino,G.,Monfrin,S.B.,Scanu,M.,etal.Marginaladaptationoffixedprosthodontics:Anewinvitro360-degreeexternalexaminationprocedure.(2004)IntJProsthodont17(2):218-223.28.Sjögren,G.,Molin,M.,Dijken,J.W.V.A10-yearprospectiveeval-uation ofCAD/CAMmanufactured (cerec) ceramic inlays cementedwith a chemically cured or dual-cured resin composite. (2004) Int JProsthodont17(2):241-246.29.Reich,S.M.,Wichmann,M.,Shortall,A.Clinicalperformanceoflarge,all-ceramicCAD/CAM-generatedrestorationsafterthreeyears.(2004)JAmDentAssoc135(5):605-612.30.Jiao,T.,Zhang,F.,Huang,X.,etal.Designandfabricationofauric-ularprosthesisbyCAD/CAMsystem.(2004)IntJProsthodont17(4):460-463.31.Coli,P.,Karlsson,S.PrecisionofaCAD/CAMTechniquefortheproduction of zirconium dioxide copings. (2004) Int J Prosthodont17(5):577-580.32.Luthardt,R.G.,Boremann,G.,Lemelson,S.,et al.An innovativemethodforevaluationofthe3-DinternalfitofCAD/CAMcrownsfab-ricatedafterdirectopticalversusindirectlaserscandigitizing.(2004)IntJProsthodont17(16):680-685.
33.Fasbinder,D.J.,Dennison,J.B.,Heys,D.R.,etal.Theclinicalper-formanceofCAD/CAM-generatedcompositeinlays.(2005)JAmDentAssoc136(12):1714-1723.34.Bindl,A.,Richter,B.,Mömann,W.H. Survival of ceramic com-puter-aideddesign/manufacturingcrownsbondedtopreparationswithreducedmacroretentiongeometry.(2005)IntJProsthodont18(3):219-224.35. Touchstone,A., Phillips, R.J. Simplifying CAD/CAM dentistry-chairside cad/cam designing andmilling are not as complex as theymayseem.(2005)DentalProductsReport(supplement1).36.Williams,R.J.,Bibb,R.,Eggbeer,D.,etal.UseofCAD/CAMtech-nology to fabricate a removable partial denture framework. (2006) JProsthetDent96(2):96-109.37.Witkowski,S.,Komine,F.,Gerds,T.Marginalaccuracyoftitani-umcopingsfabricatedbycastingandcad/cam.(2006)JProsthetDent96(1):47-52.38.Lin,C.,Chang,Y.,Chang,W.,etal.EvaluationofareinforcedslotdesignforCERECsystemstorestoreextensivelycompromisedpremo-lars.(2006)JournalofDentistry34(3):221-229.39.Trost,L.,Stines,S.,Burt,L.Makinginformeddecisionsaboutin-corporatingacadcamsystemintodentalpractice.(2006)JAmDentAssoc137:32S-36S.40.Giardano,R.Materialsforchairsidecadcamproducedrestoration.(2006)JAmDentAssoc137:14S-21S.41.Drago,C.J.Twonewclinical/laboratoryprotocolsforcad/camim-plantrestorations.(2006)JAmDentAssoc137(6):794-800.42.Fleming,G.J.P.,Dickens,M.,Thomas,L.J.,etal.Theinvitrofail-ureofall-ceramiccrownsandtheconnectorareaoffixedpartialden-tures using bilayered ceramic specimens: influence of core to dentinthicknessratio.(2006)DentalMaterials22(8):771-777.