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Dental computer-aided design/computer-aidedmanufacturing (CAD/CAM) technology isused in both dental laboratories and dentaloffices for multiple restorative applications.Chairside CAD/CAM systems for dental

offices offer dentists the opportunity to design, mill andplace ceramic restorations in a single appointment. Asimplants become the treatment of choice for fixed toothreplacement, dentists also are considering using chair-side CAD/CAM systems as a restorative solution forimplant prosthetics. A predictable CAD/CAM techniquefor dental implantology could satisfy patients’ prefer-ence for convenience and dentists’ desire for predictable,long-term restorations. Clinical research provides docu-mentation of the success of ceramic restorations createdusing the CEREC system (Sirona Dental Systems,Charlotte, N.C.).1-4 As the technology has evolved, it alsohas been used to restore dental implants.5,6

CAD/CAM TECHNOLOGY FOR DENTAL IMPLANTS

Initial attempts to fabricate implant restorations chair-side with the CEREC system included the use of felds-pathic and leucite-reinforced ceramic CAD/CAM blocks.These ceramics require adhesive bonding to be successfulin restoring natural teeth. Adhesive bonding to implantabutments remains unpredictable and reduces the relia-bility of conventional all-ceramic materials. Reports ofincreasing the occlusal thickness of the restorationbeyond the 1.5 millimeters recommended for conven-tional tooth preparations does not offset the fracture riskof adhesive glass ceramic CAD/CAM blocks used onimplant abutments.6,7 The results of the study by Wolfand colleagues6 suggest that increasing the thickness ofthe crown to an unusual 5.5 mm in combination withshortening the abutment does not result in greatercrown strength. To date, there have been no publishedclinical studies in which this type of ceramic materialwas used to restore dental implants. Despite this lack ofpublished data, the introduction of a lithium disilicateglass ceramic with 360 megapascals of biaxial flexuralstrength (IPS e.max CAD, Ivoclar Vivadent, Amherst,N.Y.) provides dentists with the option to use eithercementation or an adhesive bonding protocol. Thismaterial has the potential to be used for definitiveimplant restorations. The higher flexural strength of the

Dr. Patel maintains a private practice in general dentistry, Powell, Ohio.Address reprint requests to Dr. Patel at Infinite Smiles, 7500 SawmillParkway, Powell, Ohio 43065, e-mail “Drpatel@infinitesmiles.com”.

Integrating three-dimensional digital technologies for comprehensiveimplant dentistryNeal Patel, DDS

Background. The increase in the popularity ofand the demand for the use of dental implants toreplace teeth has encouraged advancement in clin-ical technology and materials to improve patients’acceptance and clinical outcomes. Recent advancessuch as three-dimensional dental radiographywith cone-beam computed tomography (CBCT),precision dental implant planning software andclinical execution with guided surgery all play arole in the success of implant dentistry.Methods. The author illustrates the technique ofcomprehensive implant dentistry planning throughintegration of computer-aided design/computer-aided manufacturing (CAD/CAM) and CBCT data.The technique includes clinical treatment withguided surgery, including the creation of a final res-toration with a high-strength ceramic (IPS e.maxCAD, Ivoclar Vivadent, Amherst, N.Y.). The authoralso introduces a technique involving CAD/CAM forfabricating custom implant abutments.Results. The release of software integratingCEREC Acquisition Center with Bluecam (SironaDental Systems, Charlotte, N.C.) chairsideCAD/CAM and Galileos CBCT imaging (SironaDental Systems) allows dentists to plan implantplacement, perform implant dentistry withincreased precision and provide predictable restora-tive results by using chairside IPS e.max CAD.Conclusions. The precision of clinical treat-ment provided by the integration of CAD/CAM andCBCT allows dentists to plan for ideal surgicalplacement and the appropriate thickness ofrestorative modalities before placing implants.Key Words. CAD/CAM; cone-beam computedtomography; implants; restorative dentistry; fixedprosthetics; guided implant surgery.JADA 2010;141(6 suppl):20S-24S.

A B S T R A C T

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material reduces the risk of fractureunder normal masticatory load com-pared with that of conventional glassceramic CAD blocks.7-9 The results ofthe study by Wolf and colleagues6 sug-gest that the interaction between abut-ment material and mode of cementa-tion plays an important role in theviability of conventional glass ceramicCAD/CAM materials. They noted thatthe use of adhesive resin cementincreased the overall fracture load ofconventional CAD/CAM ceramic resto-rations compared with that of nonad-hesive cements. With the recent avail-ability of a high-strength ceramicmaterial, a more favorable outcome forimplant-supported restorations mayoccur.

INTEGRATION OF CONE-BEAMCOMPUTED TOMOGRAPHY AND CAD/CAM

The primary emphasis in a surgery-focusedapproach to implant placement is on the anatomy,bone physiology and surgical success. The restora-tive demands of the case may be secondary whendetermining the placement of the implant fixture.During the restorative phase, compensation fordeviations in implant fixture location involves theuse of complex custom prosthetics components. Atechnique that requires custom prostheticsdesigned after surgical placement of the endosseousdental implant does not allow for the implant to berestored in a single visit because of the requiredlaboratory fabrication process.

Dentists need to consider the restorative goal andsurgical requirements to plan optimally for the sur-gical placement of implants. This process requires aplan for the final restoration’s optimal function,esthetics and biomechanics before making the sur-gical plan. The traditional technique for such plan-ning begins with using diagnostic casts, impressionsand clinical records. Using the diagnostic casts, thedentist or laboratory technician produces a wax-upto simulate the desired restorative outcome. A stoneduplication of the wax-up is necessary for processingeither a laboratory surgical guide to help with tradi-tional implant placement or a radiographic scanningappliance for subsequent diagnostic implant plan-ning. This work flow involves multiple patientappointments and separate laboratory proceduresinvolving the clinician and the laboratory technician

before the implant can be placed. Because of pro -cedural complexity, the clinician may favor a surgi-cally focused technique for implant placement andtreat the restorative process as secondary.

Sirona Dental Systems introduced a combinationof three-dimensional (3-D) radiographic imagingand 3-D planning by integrating CEREC Acquisi-tion Center (AC) design with Galileos (SironaDental Systems) cone-beam computed tomographic(CBCT) imaging to facilitate comprehensive implanttreatment. Galileos CEREC integration (GCI) sim-plifies restorative-focused implant placementsthrough the use of intraoral surface data (the digitalimpression) and radiographic data (Figure 1). TheGCI technique gives dentists the opportunity to planoptimum prosthetic and surgical outcomes forimplants during the diagnostic and planning phasesof treatment while minimizing the number of pro-cedures and increasing work-flow efficiency.

By using GCI software, the clinician can identifythe restorative requirements virtually, includingproper restorative material thickness around thelong axis of the planned implant, depth of restora-tive interface and emergence profile. Such infor-mation may help the dentist decide whether to use

ABBREVIATION KEY. AC: Acquisition Center.CAD/CAM: Computer-aided design/computer-aidedmanufacturing. CBCT: Cone-beam computed tomog-raphy/tomographic. GCI: Galileos CEREC integration.3-D: Three-dimensional.

Figure 1. Sidexis and Galileos implant software (Sirona Dental Systems, Charlotte,N.C.) provides tools such as nerve mapping and implant planning. Galileos CEREC(Sirona Dental Systems) integration allows for computer-aided design/computer-aided manufacturing data to be imported into software to create virtual prosthetics,giving dentists the opportunity to plan comprehensive restorative treatment in asingle visit. Image of Galileos Sidexis software reproduced with permission of SironaDental Systems, Charlotte, N.C.

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stock abutments or custom anatomic abutments.Until now, the convenience of chairside CAD/CAMfor implant restoration was limited by materialstrength. The ability to plan implant placementwith restorative vision by using the GCI softwarecombined with a restorative material whose proper-ties are an improvement over those of conventionalglass ceramics provides the dentist with a viablecomprehensive protocol for implant placement andchairside CAD/CAM all-ceramic restorative success.

CLINICAL WORK FLOWS

There are a number of possible work flows thatcan be followed when using the GCI technique.

Single-implant workflow. For a single-implant site, the clinical work flow begins withobtaining a digital impression by using CERECAC and Galileos CBCT during the initial consul-tation. Instead of using conventional impressionsand diagnostic wax-ups, the dentist can use thedigital impression to record the surface anatomyand design an ideal restoration virtually. The dig-ital impression is obtained by coating the toothand gingival surfaces lightly with an opticalreflective medium to create a uniform surface andby using the CEREC AC Bluecam to acquireimage data. Obtaining the digital impressionincludes capturing both the edentulous quadrantand the opposing quadrant in separate image cat-alogs. The virtual models created from the digitalimpression are articulated by using an additionalimage recorded when the patient is in maximumintercuspation (buccal bite technique). The den-tist or technician uses CEREC Biogeneric soft-ware (Version 3.80, Sirona Dental Systems) tocreate virtual wax-ups of planned restorationsthat include parameters such as occlusal contacts,

proximal contacts, emergence profile, proximalcontours and the desired material thickness foroptimal strength of the ceramic restoration. Inaddition to the optical impression, a GalileosCBCT scan of the patient is obtained by means ofa stock scanning bite plate (SICAT, Bonn, Ger-many). The bite plate is seated clinically by usingthe bite registration material. The bite plate isconverted to the surgical guide at a later stage.The Galileos CBCT scans provide a 3-D volumeimage of the hard tissue that can be evaluated byusing software to evaluate radiographic sectionsof the anatomy that correlate one-to-one withoutdistortion or magnification.

The CAD/CAM and CBCT systems provide com-prehensive diagnostic data. The acquisition of sur-face anatomy and radiographic anatomy dataallows the dentist to design and plan treatment andorder precision surgical guides for guided implantplacement in one visit. The process requires thedentist to combine the data sets from the two sys-tems by using GCI integration software that usessophisticated algorithms to match common datapoints. The dentist need only identify common fea-tures between the two digital images (for example,placing an identification marker on tooth no. 2 inthe CEREC AC image and on tooth no. 2 in theGalileos image) to allow the software to correlatethe data. Once combined, the CEREC AC data arevisible within the Galileos software, allowing thedentist to plan the implant position as it relates toboth the prosthetic and surgical requirements ofthe case (Figure 1). Within the software, a library ofimplant systems from which to plan implant posi-tioning relative to restorative and surgical goals isavailable. Once the dentist determines the type ofimplant and surgical positioning, he or she canorder the surgical guide. The patient’s data set andscanning template are sent to SICAT for fabricationof the implant surgical guide.

The dentist can order the surgical guide withmultiple options, including a guided pilot systemfor guided pilot osteotomy, sleeve-in-sleeve systemsfor complete guided final osteotomy or a mastersleeve for guided implant placement. The surgicalguides are compatible with most of the availableimplant systems. This work flow allows for guidedsurgical implantation during the patient’s secondvisit. Implant placement accuracy when using theSICAT surgical guides is within 500 micrometers ofplanned implant placement location.10 The SICATsurgical guide system’s inherent mean deviationrates for drilled pilot osteotomies are less than

Figure 2. Clinical photo with seated custom zirconia implant abut-ments for teeth nos. 12 through 14 and teeth nos. 18 through 20.

Copyright © 2010 American Dental Association. All rights reserved. Reprinted by permission.

JADA, Vol. 141 http://jada.ada.org June 2010 23S

500 μm even at the apical end and within 1.18˚angular deviation, and their crestal deviations aresignificantly lower than those of apical deviations.10

Once osseointegration is complete, the restora-tive phase of treatment can begin, and the dentistcan use the data from CEREC AC and Galileos thatwere used during the planning phase to understandthe restorative options in advance. The dentist canseat a stock or standard abutment clinically andscan it intraorally with CEREC AC to fabricate afull-contour restoration similar to a preparation fora crown on a natural tooth (Figure 2).

Because of the nature of stock abutments, thedentist may need to modify margin placement,reduce axial dimensions, add antirotational facetsand produce a proper tissue emergence profile byusing high-speed rotary instrumentation withcopious water irrigation to reduce heat production.To reduce the risk of heat transfer and implantdamage, modification of prosthetic componentsextraorally may be indicated. After the dentistseats the abutment clinically, he or she can fill thescrew access hole with a retrievable material to pro-tect the screw for future access. Tissue retraction isnecessary to visualize the abutment margin. Thedentist can retract the gingivae by using conven-tional means such as a retraction cord, retractiongels and pastes, and laser treatment. Once the den-tist has isolated the abutment, he or she follows theconventional chairside optical impression protocolby using CEREC AC Bluecam. Within the CERECAC software, the dentist can evaluate and confirmthe abutment’s restorative margin, interproximalcontacts, occlusal contacts, emergence profile andsoft-tissue support. Essentially, the dentist candesign a final crown by using the CEREC AC soft-

ware and customize it to fit the restorative environ-ment chairside (Figure 3). The dentist selects IPSe.max CAD and sends the data to the inLab MC XL(Sirona Dental Systems) milling chamber for chair-side computer-aided manufacturing of the crown.

After the dentist retrieves the restoration fromthe milling chamber, he or she can evaluate the res-toration clinically and adjust it if necessary while itis in the precrystallized state (Figure 4). The den-tist can introduce custom staining and glazingbefore the restoration is crystallized to final lithiumdisilicate transformation for optimal strength andesthetics (Figures 4 and 5). He or she can use adhesive (which requires that zirconia abutmentsbe pretreated with 10-methacryloyloxydecyl dihydrogen phosphate monomers) or conventionalcementation options. The dentist should removeresidual cement carefully after cementation anduse radiographic confirmation of abutment seatingand cement removal.

Custom abutment and crown work flow.Another work flow relies on the dentist’s sendingthe CEREC AC digital impression data to a dentallaboratory by using the CEREC Connect software(Sirona Dental Systems) via the CEREC inLab(Sirona Dental Systems) system to fabricate acustom abutment and crown. This abutment tech-nique may include having the dentist obtain eithera traditional fixture level impression used to fabri-cate a master implant model or a digital intraoralimpression of a clinically seated scan body on theimplant. (A scan body is a plastic coping withmarkers that provide 3-D registration of the implantlocation.) Both techniques give dentists control overmore complex and esthetic cases when they arerestoring multiple implants. Either intraorally or

Figure 3. CEREC Biogeneric software (Version 3.80,Sirona Dental Systems, Charlotte, N.C.) showing thedesign process for chairside fabrication of customimplant crowns. The image shows intraoral scan ofseated abutments for teeth nos. 18 through 20. Thecrown design for tooth no. 18 is completed and virtu-ally seated. The crown for tooth no. 19 is designed forproper emergence profile, contacts and occlusion.Image of CEREC software reproduced with permissionof Sirona Dental Systems, Charlotte, N.C.

Figure 4. Photo showing IPS e.max CAD(Ivoclar Vivadent, Amherst, N.Y.) block withprecrystallized chairside milled implantcrown no. 19 and the final crown after crys-tallization with custom staining and glazing.Image of IPS e.max CAD LT reproduced withpermission of Ivoclar Vivadent, Amherst, N.Y.

Figure 5. Clinical photo with seated IPSe.max CAD (Ivoclar Vivadent, Amherst,N.Y.) implant crowns nos. 12 through 14and crowns nos. 18 through 20.

Copyright © 2010 American Dental Association. All rights reserved. Reprinted by permission.

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on a master implant model, the dentist seats theappropriate titanium base on the implant. Then heor she introduces a scan body that allows for digitalscanning with CEREC inLab for working models(Figure 6) or CEREC AC for intraoral scanning. Forintraoral scanning, the dentist can forward the scan

data to technicians who use CEREC inLab for thedesign and milling of custom implant abutments.Using the CEREC inLab software, the technicianhas the ability to design the ideal restoration virtu-ally, perform a digital cutback technique or design afull-contour abutment that mimics conventionaltooth-borne preparations for fixed prosthodontics.Once the abutment design is complete, the techni-cian mills the zirconia restorative component withan inCoris ZI (Sirona Dental Systems) meso block,which is available in multiple shades, and sinters itfor final crystallization. The technician lutes the zir-conia meso structure to the titanium base to formthe custom abutment. Then the CEREC inLabsystem can mill the corresponding restoration, orthe dentist can seat the custom abutment for chair-side CAD/CAM restoration (Figure 6).

CONCLUSION

The integration of chairside CAD/CAM softwareand CBCT provides dentists with a combineddata set they can use for implant planning. Thismethod may allow dentists more flexibility fordelivering implant prosthetics—both milledcustom abutments and milled crowns—chairside.The digital work flow for implant dentistry andchairside CAD/CAM offers new approaches to theway dentists can practice implant dentistry. ■

Disclosure. Dr. Patel has served as a consultant to and providesclinical education courses in Galileos cone-beam computed tomographyand CEREC Acquisition Center computer-aided design/computer-aidedmanufacturing technology for Sirona Dental Systems, Charlotte, N.C.

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3. Wittneben JG, Wright RF, Weber HP, Gallucci GO. A systematicreview of the clinical performance of CAD/CAM single-tooth restora-tions. Int J Prosthodont 2009;22(5):466-471.

4. Kelly JR. Machinable ceramics. In: Mörmann WH, ed. State of theArt of CAD/CAM Restorations: 20 Years of CEREC. Hanover Park, Ill.:Quintessence; 2006:29-38.

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10. Dreiseidler T, Neugebauer J, Ritter L, et al. Accuracy of a newlydeveloped integrated system for dental implant planning. Clin OralImplants Res 2009;20(11):1191-1199.

Figure 6. Laboratory process for CEREC inLab abutments (SironaDental Systems, Charlotte, N.C.). A. A seated scan body over a tita-nium base on a fixture level implant master model. CEREC inLabsoftware (Sirona Dental Systems) allows for complete customizationof an inCoris ZI (Sirona Dental Systems) meso structure for full-contour abutment design to mimic conventional fixed prostho-dontic tooth preparation with cutback technique in CEREC inLabsoftware. B. Seated custom CEREC inLab implant abutment. C. Finalcrown seated on CEREC inLab abutment.

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Integrating three-dimensional digital technologies for comprehensive implant dentistryCAD/CAM TECHNOLOGY FOR DENTAL IMPLANTSINTEGRATION OF CONE-BEAM COMPUTED TOMOGRAPHY AND CAD/CAMCLINICAL WORK FLOWSCONCLUSION