A te

acc

with

Vygandas Rutkun

aAssociate Professor, Faculty of MedbResident, Faculty of Medicine, Divis

The Journal of Prosthetic

chnique to splint and verify the

uracy of implant impression copings

light-polymerizing acrylic resin

as, DDS, PhDa and Jevgenija Ignatovic, DDSb

Vilnius University, Institute of Odontology, Vilnius, Lithuania

Transferring the implant position from the mouth to the definitive cast is one of the most critical steps in implant pros-thodontics. To achieve a passive fit of the prosthesis, an accurate implant impression is crucial because discrepancies caninduce both biologic and technical complications. Analysis of available research data suggests that a direct (pick-up)impression technique with splinted copings is the technique of choice, particularly for multiple implants. However, thetraditional method of splinting the copings with autopolymerizing acrylic resin is a technique-sensitive and time- consumingprocedure. This report describes a straightforward method of splinting impression copings with light-polymerizingacrylic resin, with minimal amount of autopolymerizing acrylic resin. The method also can be used to verify splinting accuracy.(J Prosthet Dent 2014;111:254-256)

1 Direct impression copings placed on mandibular poste-rior implants.

2 Strip of light-polymerizing acrylic resin cut from IndividoLux (Voco GmbH) custom tray material.

Dental implants, because they donot have a periodontal ligament, are notable to compensate for even minormisfits of the superstructure.1 Therefore,recording a correct 3-dimensional ori-entation rather than surface detail isnecessary to avoid biologic and tech-nical complications.2 Many factors areinvolved in transferring the implant po-sition from the mouth to the cast,including the implant connection typeand impression coping design, thenumber of implants and angulation, theimpression technique, and the impres-sion material. Whereas the influence ofdifferent impression materials appearsto be less critical, impression techniquesare considered as a major factor thatinfluences impression accuracy.3,4 Im-plant impression copings can be repo-sitioned into the impression materialafter impression making with a closedtray (indirect, transfer) technique or canbe transferred with impression materialwith an open tray (direct, pick-up)technique. Both techniques and theirmodifications are used to achieve im-plant impression accuracy. To improvethe stability of the impression coping,splinting techniques have been adopted.Although there are conflicting dataon the effects of different impression

icine, Division of Prosthodontics.ion of Prosthodontics.

Dentistry Rutkunas and Ignatovic

3 Light-polymerizing acrylic resin strip adapted to impres-sion copings.

4 Polymerization of splint.

5 Splint was cut and rejoined with autopolymerizingacrylic resin.

March 2014 255

techniques and splinting, a systematicreview has revealed that more studiesreported higher accuracy with directtechniques when splinting was used.4

Different materials have been sug-gested for coping splinting, includingacrylic resin, plaster, polyvinyl siloxane,and polyether.5,6 The application of anautopolymerizing acrylic resin to a scaf-fold of dental floss is a common tech-nique. However, this is time-consumingand technique-sensitive procedure whenmultiple implants are to be restoredin the posterior region because unpoly-merized resin can be displaced by thecheek or tongue, and the splint canbe detached from the coping. Autopo-lymerized acrylic resins shrink duringpolymerization and generate strains.7

To compensate for acrylic resinshrinkage, the splint can be sectionedand reconnected with a small amount ofresin.8

This article describes a method tosplint impression copings with a light-polymerizing custom tray acrylic resin.The mechanical properties of light-polymerized resins have been ratedsuperior to autopolymerized resins.9

The advantages of this technique in-clude an easy and fast way to connectimpression copings (especially for mul-tiple implant-supported prostheses),better patient acceptance, the uniformcoverage of impression copings withan adequate thickness of resin, theuniform thickness of the splint, andthe avoidance of intraoral resin mono-mer. Also, the consistency of light-polymerizing resin does not require theuse of dental floss. The verification ofsplinting accuracy can be done beforeimpression making as well as after castfabrication to evaluate the accuracy ofthe cast.10 The disadvantages includepossible problems of access for the light-polymerization unit, interference withthe impression tray due to the thickerlayer of resin surrounding the impres-sion coping, inadequate adaptation ofthe light-polymerizing resin to thecoping, incomplete polymerization ofthe material, and an inability to fullyavoid the use of autopolymerized acrylicresin.

Rutkunas and Ignatovic

TECHNIQUE

1. Remove the interim abutmentsand place the direct implant impressioncopings (EZ Plus; Megagen Co) (Fig. 1).Make a radiograph to confirm the

complete seating of the impressioncoping.

2. Cut an appropriate 5-mm-widestrip of acrylic resin from the light-polymerizing custom tray material(Individo Lux; Voco GmbH) (Fig. 2).

6 Splinted copings were removed to ensure good attach-ment of material to copings and to verify passive fit.

7 Definitive impression made with high and mediumviscosity polyvinyl siloxane material.

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Wrap the resin strip around the copingsand shape with a modeling spatula toensure good adaptation of the materialand provide space beneath the splint forimpression material (Fig. 3). Light-polymerize for 60 seconds on each sidewith a 1200mW/cm2 light-intensity unit(Elipar Free Light 2; 3M/ESPE) (Fig. 4).

3. After the resin has polymerized, cutthe splint with a small diameter rotaryinstrument (D203; Hager & MeisingerGmbH) to compensate for the shrinkageand rejoin with autopolymerizing acrylicresin (Pattern Resin; GC) (Fig. 5).Confirm splinting by removing, exam-ining, and reattaching the copings(Fig. 6). Perform the Sheffield 1-screwtest to verify the accuracy of the splint.11

The Journal of Prosthetic Dentis

4. Adjust the custom tray and make adefinitive impression with polyvinyl si-loxane impression material (Take 1 Ad-vanced HB Tray and medium viscositymaterial; Kerr Corp) (Fig. 7). TheSheffield test can be performed on thedefinitive cast with the same or anadditional set of splinted copings toevaluate the accuracy of the definitivecast.12

REFERENCES

1. Cordaro L, Ercoli C, Rossini C, Torsello F,Feng C. Retrospective evaluation ofcomplete-arch fixed partial dentures con-necting teeth and implant abutments in pa-tients with normal and reduced periodontalsupport. J Prosthet Dent 2005;94:313-20.

try

2. Vigolo P, Fonzi F, Majzoub Z, Cordioli G.An evaluation of impression techniquesfor multiple internal connectionimplant prostheses. J Prosthet Dent2004;92:470-6.

3. Wostmann B, Rehmann P, Balkenhol M.Influence of impression technique andmaterial on the accuracy of multiple implantimpressions. Int J Prosthodont 2008;21:299-301.

4. Lee H, So JS, Hochstedler JL, Ercoli C. Theaccuracy of implant impressions: a system-atic review. J Prosthet Dent 2008;100:285-91.

5. Hariharan R, Shankar C, Rajan M, Baig MR,Azhagarasan NS. Evaluation of accuracy ofmultiple dental implant impressions usingvarious splinting materials. Int J Oral Max-illofac Implants 2010;25:38-44.

6. Ma J, Rubenstein JE. Complete arch implantimpression technique. J Prosthet Dent2012;107:405-10.

7. Cerqueira NM, Ozcan M, Gonçalves M, daRocha DM, Vasconcellos DK, Bottino MA,et al. A strain gauge analysis of microstraininduced by various splinting methods andacrylic resin types for implant impressions.Int J Oral Maxillofac Implants 2012;27:341-5.

8. Filho HG, Mazaro JV, Vedovatto E,Assuncao WG, dos Santos PH. Accuracy ofimpression techniques for implants.Part 2-comparison of splinting techniques.J Prosthodont 2009;18:172-6.

9. Khan SB, Geerts G. Determining the dimen-sional stability, fracture toughness and flex-ural strength of light-cured acrylic resincustom tray material. Eur J ProsthodontRestor Dent 2009;17:67-72.

10. Ercoli C, Geminiani A, Feng C, Lee H.The influence of verification jig on frameworkfit for nonsegmented fixed implant-supported complete denture. ClinImplant Dent Relat Res 2012;14(suppl 1):e188-95.

11. McDonnell T, Houston F, Byrne D,Gorman C, Claffey NJ. The effect of timelapse on the accuracy of two acrylicresins used to assemble an implantframework for soldering. Prosthet Dent2004;91:538-40.

12. Sadid-Zadeh R, O’Neal SJ, Liu PR, Aponte-Wesson R. A technique for verifying implantanalog positions in the definitive cast.J Prosthet Dent 2013;109:192-7.

Corresponding author:Dr Vygandas Rutkunasno. 217 Zalgirio Street 11508217 VilniusLITHUANIAE-mail: vygandasr@gmail.com

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

Rutkunas and Ignatovic