Useandstrurest

Wei-Shao Lin, D

aAssistant Professor, Department ofbAssistant Professor, Department ofcAssistant Professor, Department ofdAssociate Professor, Department ofeDirector, Advanced Education in Pr

Lin et al

of prefabricated titanium abutmentscustomized anatomic lithium disilicatectures for cement-retained implantorations in the esthetic zone

DS,a Bryan T. Harris, DMD,b

Amirali Zandinejad, DDS, MSc,c William C. Martin, DMD, MS,d andDean Morton, BDS, MSe

School of Dentistry, University of Louisville, Louisville, Ky; College ofDentistry, University of Florida, Gainesville, Fla

This report describes the fabrication of customized abutments consisting of prefabricated 2-piece titanium abutments andcustomized anatomic lithium disilicate structures for cement-retained implant restorations in the esthetic zone. The heat-pressed lithium disilicate provides esthetic customized anatomic structures and crowns independently of the computer-aideddesign and computer-aided manufacturing process. (J Prosthet Dent 2014;111:181-185)

Customized anatomic abutmentsare often provided to improve or opti-mize esthetic outcomes in implantdentistry. The esthetic improvementis associated with the color of thematerial in the submucosal periimplantregion and improved periimplantemergence profile. In addition, appro-priately contoured abutments canreduce the likelihood of complicationsassociated with residual luting agentby improving cement margin accessi-bility.1 Abutments with customizedperiimplant emergence form and colorcan be fabricated from zirconia andwith computer-aided design/computer-aided manufacturing (CAD/CAM)technology.2,3 A systematic review4 con-cluded that implant-supported zirconiarestorations in the esthetic zone shouldbe used with caution, because limitedclinical evidence of their performanceis available.5,6 The use of CAD/CAMtechnology can improve the speed,simplicity, and efficiency of manufac-ture of zirconia abutment components.7

Zirconia also has limitations. Theseinclude the material’s inherent opacityand the consequent higher value ofthese restorations when compared with

Oral HealOral HeaOral HealOral andosthodon

the adjacent teeth and the restorationssupported.8 To provide consistentesthetic properties on implant restora-tions supported by zirconia abutments,various attempts have been made tocreate a tooth-colored zirconia abut-ment that more closely mimics theshade of natural teeth.4 Coloring metaloxides can be added into zirconiaceramic before the sintering process.7,9

In addition, adding heat-pressed fluo-rapatite glass ceramic to the sub-gingival portions of zirconia abutmentsmay provide improved esthetic out-comes in the event of periimplant softtissue recession.8,10

An experimental customized anat-omic abutment design combining goldalloy and lithiumdisilicatewas proposedand had significantly higher fractureload when compared with commerciallyfabricated zirconia abutments.11 How-ever, the design with pressed lithiumdisilicate ceramic (IPS e.max Press; Ivo-clar Vivadent) around the anatomic goldalloy abutment may be cost-inhibitive ina clinical setting because ofmaterial cost(Type IV gold alloy).11

This report describes a techniquefor the fabrication of customized

th and Rehabilitation.lth and Rehabilitation.th and Rehabilitation.Maxillofacial Surgery, Center for Implant Denttics; and Professor and Chair, Department of O

anatomic lithium disilicate structuresluted onto prefabricated 2-piece tita-nium abutments. The combinationprovides esthetic abutments (titanium/lithium disilicate) and is designed tosupport cemented restorations in theesthetic zone.

TECHNIQUE

First clinical appointment

1. Complete an intraoral examinationof the existing implant-supported interimrestorations and the periimplant softtissue to confirm the desired functionaland esthetic outcome (Fig. 1).

2. Remove the implant-supportedinterim restorations and make a defin-itive implant-level impression; use cus-tomized impression copings to capturethe emergence profile of the interimrestorations (RC impression post forclosed tray; Straumann USA, LLC).8

Make the definitive impression with acustom tray and polyvinyl siloxaneimpression material (Aquasil UltraLight and Heavy Body; Dentsply Caulk).

3. Pour the impression with polyvinylsiloxane material (Softissue Moulage;

istry.ral Health and Rehabilitation.

1 Existing implant-supported interim restorations (maxillarycentral incisors).

2 Facial matrix fabricated around interim restorations ondefinitive cast.

3 Two-piece prefabricated titanium abutments with minimalgingival height are selected and connected to definitive cast.

182 Volume 111 Issue 3

Kerr Dental Laboratory Products) andType IV dental stone (Silky-Rock; WhipMix Corp) to obtain a definitive cast witha removable resilient gingival replica.

The Journal of Prosthetic Dentis

4. Reposition the implant-supportedinterim restorations onto the definitivecast, and fabricate a facial matrix withpolyvinyl siloxane putty (Sil-Tech; Ivoclar

try

Vivadent), capturing the form of boththe interim restoration and the definitivecast (Fig. 2).12

Laboratory procedure

1. Select the corresponding pre-fabricated titanium abutments withminimal gingival height and abutmentdiameter (RC 2-piece abutment withdiameter of 5.0 mm, gingival height of1.0 mm, and abutment height of 5.5mm; Straumann USA, LLC) and con-nect them to the definitive cast (Fig. 3).Adjust the height of the titaniumabutment by using the facial matrix asa reference. Ensure adequate clearancein each dimension for fabrication ofoptimized definitive crowns.

2. Develop wax patterns for thestructures on the prefabricated titaniumabutments by using the facial matrixand removable resilient gingival replicaas references to achieve the desiredabutment shape, emergence profile,and finish line level (Fig. 4). Ensure aminimum thickness of 0.5 mm of thewax to follow the manufacturer’s rec-ommendations for the lithium disilicatepressable ceramic (HO ingot, IPS e.maxPress; Ivoclar Vivadent).

3. Remove the wax patterns fromthe prefabricated titanium abutmentsand invest with phosphate-bondedinvestment material (IPS PressVESTSpeed; Ivoclar Vivadent). Heat-pressand devest the structures according tothe manufacturer’s recommendationsfor lithium disilicate pressable ceramics(HO ingot, IPS e.max Press; IvoclarVivadent) (Fig. 5).

4. Verify the fit of the individualstructures on the prefabricated titaniumabutments with polyvinyl siloxane mate-rial (Fit Checker Black; GC America) andadjust with a low-speed dental handpieceand rotary instruments (LD13M LDgrinder pink medium; Brasseler USA).

5. Develop the wax patterns of thedefinitive crowns to fit on the assemblyof customized anatomic lithium dis-ilicate structures and prefabricated2-piece titanium abutments. Investthe wax patterns and heat-press the

Lin et al

4 Customized wax patterns on 2-piece titanium abutments,illustrating desired morphology, emergence profile, and finishline position for structures.

5 Devested lithium disilicate pressable ceramic structures.

6 Completed customized anatomic titanium/lithium disili-cate abutments and definitive lithium disilicate crowns.

March 2014 183

definitive crowns with lithium disilicatepressable ceramics (LT ingot, IPS e.maxPress; Ivoclar Vivadent).

6. Complete the characterizationand glazing process for both the

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lithium disilicate structures and thedefinitive crowns with low-fusingnanofluorapatite glass ceramic (IPSe.max Ceram Shades and Essences;Ivoclar Vivadent) (Fig. 6), and ensure

glaze material is absent from the inter-face between the lithium disilicatestructures and the definitive crowns.

7. Abrade the surface of the titaniumabutments above the finish line withaluminum oxide (Aluminum OxideBlasting Media, 50 Micron; BuffaloDental) under 0.1 MPa pressureto achieve a matte surface. Apply prim-er (Monobond Plus; Ivoclar Vivadent)onto the abraded surface for 60 secondsand air dry the surface (Fig. 7A).

8. Etch the intaglio surface of thelithium disilicate structures with 5%hydrofluoric acid gel (IPS CeramicEtching Gel; Ivoclar Vivadent) for 20seconds (see Fig. 7B). Rinse, air drythe surface, and apply the primer(Monobond Plus; Ivoclar Vivadent) tothe treated surface for 60 seconds andair dry.

9. Seal the access openings of thetitanium abutments with cotton pellets.Lute the lithium disilicate structuresto the prefabricated titanium abut-ments with dual-polymerizing resincement (Multilink Implant; IvoclarVivadent). Remove the excess cementfrom the completed customized tita-nium/lithium disilicate abutments (seeFig. 7C).

Second clinical appointment

1. Remove the interim implant-supported restorations and secure thetitanium/lithium disilicate abutmentsto the implants. Adjust the definitivecrowns to achieve satisfactory contacts(occlusal and interproximal) and es-thetic and functional outcomes.

2. Etch, rinse, and dry the inta-glio surface of the lithium disilicatecrowns and the ceramic surface of thetitanium/lithium disilicate abutmentsaccording to manufacturers’ instruct-ions. Apply the primer to all treatedlithium disilicate surfaces for 60 sec-onds and air dry.

3. Seal the access openings of the ti-tanium/lithium disilicate abutmentswith cotton pellets. Lute the definitivecrowns to the titanium/lithium disilicateabutments with dual-polymerizing resincement (Multilink Implant; Ivoclar

7 Luting procedures for titanium/lithium disilicate abutments. A, Matte titanium surface achieved with aluminum oxideabrading. B, Intaglio surfaces of lithium disilicate structures treated with 5% hydrofluoric acid gel. C, Luted titanium/lithiumdisilicate abutments.

8 Definitive customized anatomic titanium/lithium disilicateimplant abutments and lithium disilicate crowns at 6-monthfollow-up appointment.

184 Volume 111 Issue 3

Vivadent) and remove the excess cement(Fig. 8).

DISCUSSION

Although CAD/CAM technologyis commonly used to fabricate

The Journal of Prosthetic Dentis

customized zirconia implant abutments,the limitations of CAD software andthe experience of the dental labora-tory technician in the field of digitaldentistry may prevent ideal digital abut-ment/restoration design and restrict theesthetics of definitive restorations. In

try

addition, the compatibility of internalconnections between zirconia abutmentsand the titanium implants may be lessthan optimal. The described techniquecan be used to fabricate a customizedanatomic abutment independent ofCAD/CAM with conventional dentallaboratory techniques.

In the current report, both theabutments and definitive crowns werefabricated with heat-pressed lithiumdisilicate with similar characterizationand glazing processes. Therefore, theabutments in the periimplant mucosalregion were of a shade closer to therestorations they supported and mayprovide improved long-term estheticoutcomes in patients with thin tissuebiotype. Furthermore, because of im-proved shade matching between theabutment and the definitive restoration,the restoration finish line design maybe optimized at the equigingival orsupragingival level, thereby improving

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March 2014 185

access for the removal of excess lutingagent.

Some limitations are associated withthis technique. Compared with a CAD/CAM customized zirconia abutment, thetitanium/lithium disilicate abutment as-sembly consumes more restorative spacewith its multiple layers of materials.Additional laboratory steps and costs areneeded for this technique and includeindividual waxing, heat-pressing, anddevesting procedures for both the lithiumdisilicate structure and the crown.

REFERENCES

1. Guess PC, Att W, Strub JR. Zirconia in fixedimplant prosthodontics. Clin Implant DentRelat Res 2012;14:633-45.

2. Gomes AL, Montero J. Zirconia implantabutments: a review. Med Oral Patol Oral CirBucal 2011;16:e50-5.

3. Lin WS, Harris BT, Morton D. The use of ascannable impression coping and digitalimpression technique to fabricate a custom-ized anatomic abutment and zirconia resto-ration in the esthetic zone. J Prosthet Dent2013;109:187-91.

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4. Nakamura K, Kanno T, Milleding P,Ortengren U. Zirconia as a dental implantabutment material: a systematic review. Int JProsthodont 2010;23:299-309.

5. Kim JS, Raigrodski AJ, Flinn BD,Rubenstein JE, Chung KH, Mancl LA. Invitro assessment of three types ofzirconia implant abutments understatic load. J Prosthet Dent 2013;109:255-63.

6. Foong JK, Judge RB, Palamara JE, Swain MV.Fracture resistance of titanium andzirconia abutments: an in vitro study.J Prosthet Dent 2013;109:304-12.

7. Kohal RJ, Att W, Bächle M, Butz F.Ceramic abutments and ceramic oralimplants: an update. Periodontol 20002008;47:224-43.

8. Wadhwani CP, Piñeyro A, Akimoto K.An introduction to the implant crownwith an esthetic adhesive margin (ICEAM).J Esthet Restor Dent 2012;24:246-54.

9. Shah K, Holloway JA, Denry IL.Effect of coloring with various metaloxides on the microstructure, color,and flexural strength of 3YTZP.J BiomedMater Res B Appl Biomater 2008;87:329-37.

10. Oates TW, West J, Jones J, Kaiser D,Cochran DL. Long-term changes insoft tissue height on the facial surfaceof dental implants. Implant Dent 2002;11:272-9.

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11. Kim S, Kim HI, Brewer JD, Monaco EA Jr.Comparison of fracture resistance ofpressable metal ceramic custom implantabutments with CAD/CAMcommercially fabricated zirconia implantabutments. J Prosthet Dent 2009;101:226-30.

12. Lin WS, Ercoli C. A technique for indirectfabrication of an implant-supported, screw-retained, fixed provisional restoration inthe esthetic zone. J Prosthet Dent 2009;102:393-6.

Corresponding author:Dr Wei-Shao LinDepartment of Oral Health and RehabilitationUniversity of Louisville501 S. Preston StreetLouisville, KY 40202E-mail: WeiShao.Lin@Louisville.edu

AcknowledgmentsThe authors thank Roy Dental Laboratory, NewAlbany, IN for assistance with this treatment.

Copyright ª 2014 by the Editorial Council forThe Journal of Prosthetic Dentistry.

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