CAD/CAM technology and all-ceramic sys-tems have become integral parts of mod-ern dentistry and laboratory technology.

The Procera system1 (Nobel Biocare, Göteborg,Sweden) was introduced over a decade ago andoffers various components, materials, and tech-niques within one concept (C&B&I: crown &bridge & implant, Nobel Biocare). The CAD/CAMsystem allows fabrication of single- and multiple-unit frameworks as well as implant components(Procera Crown, Procera Bridge, Procera Abut-

ment). Each of these restorative components canbe fabricated from titanium alloy, densely sinteredaluminum oxide ceramic (Alumina), or densely sin-tered zirconium oxide ceramic (Zirconia).

The advantages, properties, and clinical appli-cations of the all-ceramic components and materi-als used with the Procera system, based on scien-tific evidence, are discussed in this article. Thefeatured case presentation, a comprehensive full-mouth rehabilitation, demonstrates the versatilityand esthetic capabilities of the Procera system.

ALUMINUM OXIDE CERAMICSHigh-strength ceramic materials (eg, aluminumoxide and zirconium oxide) are typically used ascoping materials for full-coverage restorations andfixed partial denture frameworks.2–5 CAD/CAMtechnology compensates for the significant shrink-age of metal oxide high-strength ceramic materialsduring sintering. An industrialized production pro-

1Affiliate Associate Professor, University of WashingtonSchool of Dentistry, Seattle, Washington, USA; private prac-tice, San Sebastian, Spain.

2Professor of Restorative Dentistry and Chairman, Depart-ment of Preventive and Restorative Sciences, University ofPennsylvania School of Dental Medicine, Philadelphia, Pennsylvania, USA.

Correspondence to: Dr Iñaki Gamborena, Resurecccion MªDe Azkue, 6, 20018 San Sebastian, Spain. E-mail: gambmila@arrakis.es

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COMPREHENSIVE ESTHET IC AND FUNCT IONAL REHABILITAT ION WITH ACAD/CAM ALL-CERAMIC SYSTEM

Iñaki Gamborena, DMD, MSD, FID1

Markus B. Blatz, DMD, PhD2

cess bears multiple advantages in respect to theunique sintering temperatures and conditions ofhigh-strength ceramics and outsourcing of a criticallaboratory procedure. Procera uses densely sin-tered, high-purity aluminum oxide (>99.9%) ceram-ics, which offer a flexural strength of 610 MPa.6 Pro-cera Alumina has a higher degree of translucencycompared to Procera Zirconia and may, therefore,be preferred in anterior, low-pressure-bearingareas of esthetic significance.4,5 Alumina is used forsingle crowns, implant abutments, and laminate ve-neers.2 The clinical long-term success of ProceraAlumina crowns has been validated in many clinicalstudies.7–9 Most recently, Galindo et al10 reported onthe follow-up of 39 patients with 135 Procera Alu-mina crowns. The cumulative survival rate was 99%after 5 and 7 years.

Z IRCONIUM OXIDE CERAMICSZirconium oxide ceramics provide superior physicalproperties (high flexural strength), biocompatibility,and excellent esthetics.4,5 The inherent strength ofzirconia makes it useful in a variety of clinical appli-cations including full-coverage crowns, resin-bonded fixed and conventional fixed partial den-tures, implant abutments, and even long-spanimplant bars.11,12 Lifetime predictions reveal favor-able success rates for zirconium oxide ceramicrestorations.13 In dentistry, zirconium oxide (ZrO2)ceramic is mostly used in a tetragonal crystallinephase, partially stabilized with yttrium oxide. Poly-crystalline zirconium oxide ceramics provide a flex-ural strength greater than 1,000 MPa and feature aunique material property: active crack resistance.External forces transfer the partially stabilizedtetragonal particle into a monoclinic form. Thenewly acquired monoclinic form has an increasedvolume, which gives the material the ability to closea crack (transformation toughening).4,5

VENEERING CERAMICS FOR H IGH -STRENGTH CERAMIC COPINGS

High-strength ceramic copings are veneered withfeldspathic (or silica-based) ceramics, which havea low flexural strength but offer superior estheticsand high translucency.2,3 Feldspathic veneeringceramics for metal-alloy copings typically fail toprovide long-term bonds and adequate physicalproperties when fired to high-strength ceramicsdue to a mismatch in the thermal coefficient ofexpansion, weak ceramic-ceramic bonds, and lowfracture strength. Aboushelib et al14 summarizedin an in vitro study that cone cracking of the ve-neering ceramic is the dominant mode of failureof layered all-ceramic restorations. They concludethat higher strength veneering ceramics areneeded to exploit the high strength of zirconia.Newer veneering ceramics and bonding methodsmodified for alumina and zirconia copings providehigher strengths and improved bonding mecha-nisms that seem to prevent delamination and frac-tures. Shear bond strengths of three recently de-veloped veneering ceramics to zirconium oxideceramic were investigated by Blatz et al.15 Interest-ingly, all ceramic-ceramic combinations were dif-ferent from each other but significantly strongerthan the metal-ceramic control.

CEMENTAT IONCementation materials and methods play a criticalrole in the clinical survival of ceramic restora-tions.16–18 Oppes et al19 conducted an in vitro studyon the marginal seal and fracture strength of Pro-cera Alumina crowns after exposure in an artificialchewing simulator. They concluded that the typeof luting agent has a significant effect on the frac-ture strength and microleakage of all-ceramiccrowns. Bonding with a composite resin lutingagent containing adhesive phosphate monomers

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significantly increased the fracture strength andimproved the marginal seal of alumina crowns.However, all luting agents used in this investiga-tion provided fracture strengths well above theaverage physiologic chewing forces. Okutan etal20 investigated the fracture load and marginal fitof shrinkage-free (ZrSiO4) all-ceramic crowns afterchewing simulation. In this study, using adhesivecomposite resin cement resulted in higher meanfracture loads, which were, however, not statisti-cally different from glass-ionomer cement. Evenwith a reduced coping thickness of 0.4 mm, zirco-nium oxide ceramic seems to provide adequatestrength for nonadhesive cementation.21

CERAMIC IMPLANT ABUT-MENTSConventional metal abutments may cause graydiscoloration of the surrounding gingiva. Alu-minum oxide or zirconium oxide ceramic implantabutments prevent this phenomenon.22 Clinicalstudies demonstrate that zirconium oxide ceramicabutments had a cumulative survival rate of 100%after 4 and 6 years follow-up.23,24 While zirconiumoxide ceramic offers almost twice the strength,aluminum oxide ceramic abutments feature someesthetic advantages.25 Att et al26,27 investigatedthe strength of Procera zirconia and aluminacrowns in combination with titanium, zirconia,and alumina abutments after exposure in an artifi-cial chewing simulator. All material combinationsexceeded physiologic chewing forces in the ante-rior jaw. Fracture strengths of zirconia crownswere significantly different when used with eitherone of the abutment materials.26 The combinationof zirconia crowns and alumina abutments re-sulted in the lowest fracture strengths. On theother hand, alumina crowns yield similar strengthwhen used with either zirconia or alumina abut-ments and were comparable to the zirconia-zirconia combination.27 Therefore, alumina abut-ments should preferably be used with alumina

crowns while zirconia abutments can be usedwith either crown material.

ALL-CERAMIC FIXED PART IAL DENTURESDistinctive multidirectional forces and biomechanicrequirements in the connector/pontic areas makezirconia the preferred framework material for all-ce-ramic multiple-unit fixed partial dentures. Studart etal28 concluded from a recent study that “in spite ofthe susceptibility to subcritical crack growth, calcu-lations based on the fatigue parameters and on thestress applied on the prosthesis indicate that poste-rior bridges with zirconia frameworks can exhibitlifetimes longer than 20 years if the diameter of thebridge connector is properly designed.” Whileshort-term clinical studies reveal promising successrates, long-term data are still needed to confirmthe reliability of zirconia fixed partial dentures.29

CASE PRESENTAT IONA 70-year-old man presented with failing restora-tions (Figs 1 and 2). The existing full-mouth rehabili-tation was less than 2 years old and he complainedof difficulty with chewing and function. The initialclinical and radiographic examination revealedheavy horizontal bruxism. The occlusal scheme waslocked in position by the existing restorations with-out anterior or lateral freedom (overjet and immedi-ate anterior disclusion). Reduced opening of thevertical dimension of occlusion contributed to anexcessive load to the anterior teeth, which causedthe restorations to fracture. The crowns were looseand the abutments were decayed to the gingivalmargin (Figs 3 and 4). Existing implants (3i ImplantInnovations, Palm Beach, FL, USA) in the areas ofthe maxillary right first premolar to first molar andleft first and second molars were well integratedand could be preserved for future restorations.Some mandibular restorations revealed recurrentcaries. The periodontal diagnosis included ad-

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vanced generalized gingivitis with localized peri-odontitis.

The comprehensive restorative treatment plan in-cluded implant-supported restorations in the maxillaand tooth-supported restorations in the mandible.

Remaining roots in the maxilla were extractedand immediately replaced with seven implants (Re-place Select HA, Nobel Biocare) in a flapless proce-dure (Figs 5 and 6). Different implant diameterswere used to maximize implant-to-bone contact: 5mm for the central incisors, canines, and left second

CASE PRESENTATION

Figs 1 and 2 Failing full-mouth restoration in a 70-year-old patient. Initial clinical situation.

Figs 3 and 4 Preoperative intraoral frontal view offailing restorations.

Figs 5 and 6 Dental implants were placed with aflapless surgical procedure immediately after extrac-tion of the destroyed teeth.

1 2

3 4

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molar; 4.3 mm for the right lateral incisor; and 3.5mm for the left lateral incisor. All implants wereplanned to be immediately loaded with provisionalabutments and fixed full-arch provisional restora-tions, which were fabricated from the diagnosticwaxup. After placement of all implants, temporaryabutments (titanium temporary direct abutments,Nobel Biocare) were screwed onto the implants andused as impression copings to transfer the three-dimensional position of the implants to a stone cast.At this stage, the titanium abutments were pre-pared and the cast was trimmed around each im-plant to create an emergence profile that matchedthe contour of the teeth in the diagnostic waxup.Each individual emergence profile was created byapplying a light-cure composite resin (Tetric CeramHB, Ivoclar Vivadent, Schaan, Liechtenstein) into thecarved stone and 360 degrees around the implantabutment to create a customized abutment. Thecomposite resin was cured in the laboratory (Triad2000, Visible Light Cure System, Dentsply/Trubyte,York, PA, USA) and prepared with diamond burs toits ideal abutment form.

The customized provisional abutments (titaniumtemporary abutments and composite profile) wereconnected to the implants, and the full-arch shellprovisional restoration was relined directly in thepatient’s mouth. The screw access holes of all abut -ments were carefully filled with a light-cure tempo-rary material (Fermit, Ivoclar Vivadent). The abut-ments were isolated with petroleum jelly beforerelining the provisional restoration with a self-cureacrylic material (Temporary Bridge Resin, Caulk/Dentsply). The provisional restoration was re-moved after polymerization. Each abutment wasunscrewed and the margins were finalized in thelaboratory for optimal fit. The abutments wereretightened (Fig 7) and the provisional restorationseated to be adjusted to the mandible. In themeantime, the existing mandibular crowns wereremoved and the abutment teeth were prepared.The mandibular full-arch provisional shell was re-lined and occlusion adjusted against the maxilladuring the same visit. The provisional restorationswere cemented with temporary cement (Temp-Bond NE, Kerr, Orange, CA, USA) after final ad-justments, recontouring, and polishing (Fig 8).

7 8

9

Fig 7 Intraoral view of temporary implantabutments customized with light-cure composite.

Fig 8 Full-mouth provisional restorations wereplaced immediately after insertion of the implants.

Fig 9 After 6 months, new provisional restora-tions were fabricated in the laboratory to com-pensate for gingival recession.

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Gingival recession of 1 to 2 mm was observed6 months after tooth extraction and immediateimplant placement. The provisional abutmentswere recontoured and new provisional restora-tions were fabricated in the laboratory (Fig 9) tocompensate for the missing soft tissue. Duringthat period, additional implants were placed to re-store both mandibular first molars (5 13-mmStraight Replace Select HA, Nobel Biocare). Peri-

odic follow-up visits did not reveal any looseningof the provisional restorations, which demon-strated an adequate occlusal scheme. Optimalfunctional and esthetic parameters were estab-lished during the provisional phase (Figs 10 and11), which could then be transferred to the finalrestorations.

Final impressions of the mandible were takenwith the double-cord technique (#000 and #0 Ul-

�

10 11

12 13

14 15

Figs 10 and 11 Extraoral and intraoral views of the provisional restorations.

Figs 12 to 15 Temporary plastic abutments were modified on the cast and tried intraorally forfabrication of customized implant abutments. A silicone index was used to verify optimal contourand position.

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trapak, Ultradent, South Jordan, UT, USA) and thedouble-mix impression technique (Virtual VPSputty base regular set and extra-light-body fastset, Ivoclar Vivadent). A pickup impression of themaxillary full-arch provisional restoration wastaken with the double-mix technique (Virtual VPSputty base regular set and extra-light-body fastset). The provisional restoration was embeddedand locked into the impression material upon re-moval. The abutments were unscrewed and re-moved from the mouth, and laboratory implantanalogues were connected to the correspondingprovisional abutments. The provisional cementwas left in place for precise fit and transfer of thetissue topography and implant position to themaster cast (GC Fuji-Rock EP Pearl White color,GC, Alsip, IL, USA). Cross-mounted casts were se-lected to facilitate and transfer the provisional in-formation to the fabrication of the final prosthesis.Acrylic jigs (GC Pattern Resin) were used in addi-tion to interocclusal wax registrations (bite registra -tion wax sheets, Almore International) to maintainthe same vertical dimension as established in theprovisional restorations.

Materials for the final restorations were se-lected at this stage. It was decided to apply allcomponents of the Procera product line, singlecrowns, implant abutments, and fixed partial den-tures, and to take advantage of the unique mate-rial properties of zirconia (implant abutments, pos-terior restorations, and fixed partial dentures) andalumina restorations (anterior crowns). Cus-tomized gold abutments were planned for the ex-isting implants in the posterior maxilla.

Two master casts were fabricated from eachimpression. One was sectioned into individualdies to facilitate scanning of each abutment andpontic site. The second cast was solid and dupli-cated the provisional restoration for a stable refer-ence of the soft tissue contour and fabrication ofzirconia abutments. A silicone index was madefrom this cast (Zetalabor laboratory high-precisioncondensation silicone, Zhermack, Badia Polesine,Italy).

The fabrication of a customized zirconia abut-ment begins with a temporary plastic direct abut-ment (Nobel Biocare) (Fig 12) that is modified withcomposite to its ideal contour and form according

17 18

16

Fig 16 Definitive implant abutments were fab-ricated from zirconia (anterior) and gold (poste-rior).

Figs 17 and 18 Optimal contour and ade-quate tissue support of the implant abutmentsis verified on the master cast and confirmed intraorally.

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to the silicone index made from the provisionalrestoration (Fig 13). The customized plastic abut-ments should be tried in the mouth and verifiedwith the silicone index (Figs 14 and 15) before finalscanning and fabrication of the definitive implantabutments (Figs 16 to 18). The Procera Forte scan-ner (Nobel Biocare) was used to scan the multiple-unit restorations, the temporary plastic abutments,

the mandibular preparations, and the ponticridges as well as the interocclusal records. Materialthickness, height, contour, and all other dimen-sions of the abutments, copings, and frameworkswere individually designed on the computer.

All definitive copings and frameworks weretried intraorally to verify fit on the prepared teethand customized abutments (Figs 19 to 22). Pickup

19 20

21 22

23 24

Figs 19 to 22 Occlusal views of definitive copings and frameworks on the master casts and dur-ing clinical try-in on the prepared teeth and customized abutments. All posterior restorations weremade with Procera Zirconia copings. Maxillary incisors and mandibular anterior teeth were re-stored with Procera Alumina.

Fig 23 Pickup impression of mandibular copings.

Fig 24 Solid master cast of the mandibular pickup impression with copings in place.

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31

Fig 32 Detailed intraoral labial view of mandibular anterior ceramic copings.

Fig 33 Detailed labial view of mandibular anterior restorations on solid master cast.

Fig 34 Postoperative intraoral labial view of mandibular anterior restorations.

25 26

27 28

30

Fig 25 Definitive maxillary restora-tions on sectioned master cast.

Fig 26 Postoperative intraoral occlusal view of maxillary restora-tions.

Fig 27 Occlusal view of definitivemandibular restorations on themaster cast.

Fig 28 Postoperative intraoral occlusal view of mandibularrestorations.

32 33 34

29

Fig 29 Detailed labial view of maxillary anteriorrestorations on solid master casts.

Fig 30 Occlusal view of anterior maxillary zirconiaabutments.

Fig 31 Postoperative intraoral labial view of maxil-lary anterior restorations.

impressions (Virtual VPS) were taken of all cop-ings and frameworks to fabricate solid mastercasts with an accurate tissue topography (Figs 23and 24). Sufficient space for the veneering porce-lain was verified with silicone indices. The veneer-ing ceramic was applied and the full-mouthrestorations were tried in at the bisque-bakestage. The restorations were then finalized,glazed, and stained to create natural esthetics(Figs 25 to 34). The zirconia abutments were

tightened with a torque of 35 Ncm and screw ac-cess holes were closed with a light-cure tempo-rary restorative material (Fermit, Ivoclar Vivadent)before final cementation. Adhesive resin (RelyXUnicem Transparent, 3M ESPE, St Paul, MN,USA) was used for definitive insertion of the im-plant restorations while RelyX luting (3M ESPE)was used for the mandibular natural dentition.Figures 35 to 38 show postoperative views. Afterdefinitive insertion, a panoramic radiograph was

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35 36

37

3938

Fig 35 to 37 Postoperative extraoral views.

Fig 38 Postoperative intraoral labial view.

Fig 39 Postoperative panoramic radiograph.

taken (Fig 39) and an occlusal splint was deliv-ered to protect the restorations during sleep.

CONCLUSIONScientific evidence, physical properties, and thevast clinical possibilities of the Procera CAD/CAMall-ceramic system have been discussed and illus-trated in this article. While the existing evidencedemonstrates excellent clinical longevity of high-strength all-ceramic restorations, further researchwill be necessary to fully explore their advantagesand to apply them in the most favorable manner.

ACKNOWLEDGMENTS The authors thank Dr Pedro Peña for the excellent implantsurgery, Mr Iñigo Casares for the design and scanning of thecopings and frameworks, and Dale Denny for the beautifulporcelain work featured in the case presentation.

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26. Att W, Kurun S, Gerds T, Strub JR. Fracture resistance ofsingle-tooth implant-supported all-ceramic restorationsafter exposure to the artificial mouth. J Oral Rehabil2006;33:380–386.

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