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INTRODUCTION Part 1 of this series dealt with the creation ofan emergence profile prior to implant place-ment, along with implant placement andprovision of an immediately-loaded fixedpartial denture (FPD) used to support andmaintain the created profile. In part 2, theauthors’ technique for the duplication of thecreated emergence profile will be demon-strated. This technique provides both accu-rate working models and a predictably-shaped final prosthesis, making use of astent that accurately replicates the fit sur-face of the provisional fixed prosthesis.

Observations Related to the Technique In order to follow the steps described laterin this article, it is important to understandthe following points:

l Although the technique described inthis case relates to the NobelActive (NobelBiocare) implant system, it can also beadapted to other implant systems.

l Irrespective of the implant systemused, it is important to select the tallestimpression coping available to allow ade-quate clearance for the initial splinting ofthe impression copings intraorally, andsubsequent stent creation. For example, theopen-tray impression copings available forthe NobelBiocare Replace System are short-er than the open-tray copings; in the casepresented herein, the authors have used theclosed-tray copings, with an open-trayimpression technique as described below.

l The provisional FPDs used to createthe emergence profile, whether the imme-diate load as shown in this article or onefabricated at a later stage of treatment, areusually constructed on nonengaging,screw-retained titanium temporary abut-ments. In order to ensure that the implant

head orientation is accurately reproducedin the working laboratory model, it is nec-essary to begin the stent fabrication bysplinting the chosen impression copingsintraorally.

The TechniqueThe case described in part 1 of this article isshown prior to removal of the immediate-

load FPD (Figure 1), after a 4-month healingperiod. Although it is not within the scopeof this article to describe the details of thetechnique used to refine the emergenceprofile, which may sometimes take placeduring several visits, the final profileachieved is shown on removal of the provi-sional FPD just prior to stent creation(Figure 2).

The clinical steps involved in creatingthe impression stent are as follows:

1. Since the implants placed in this casewere 2 NobelActive RP implants, 2 open-tray impression copings (narrow) were fit-ted, and a check-radiograph was taken atthis time to ensure that the copings werecorrectly seated within the implants. Thecopings were then splinted together using

an old bur and a light-cured resin (Triad Gel[DENTSPLY Caulk]) (Figure 3). In order tominimize the effect of polymerizationshrinkage, it is advisable to apply and curethe resin on one coping before applyingand curing the resin on the other.

2. The splinted impression copingswere then carefully removed from themouth (Figure 4a), ensuring that there wasno movement of one in relation to theother, and analogue replicas were securelyfitted to the copings. Next, these replicaswere also splinted together using an old burand light-cured resin as described in Step 1(Figure 4b).

3. The splinted replicas were then care-fully removed from the impression cop-ings (Figure 4c) and the provisional FPDsecurely fitted to the splinted replicas(Figure 4d).

Tom Bereznicki,BDS (Edin)

AndrewDawood, MRD,RCS, MSc, BDS

The Creation of an Emergence Profile, Part 2

continued on page 70

Figure 1. The provisional fixed prosthesis is shown

after a 4-month period of osseointegration.

Figure 2. The created emergence profile, upon

removal of the prosthesis.

Figure 3. The splinted impression copings, in place.

AESTHETICS

Pontic-Guided Implant Placement in the Aesthetic Zone

This is part 2 of a 2-part article series. Part 1of Drs. Bereznicki and Dawood’s article waspublished in the April 2012 issue of DentistryToday and can be found in our archived articles on dentistrytoday.com.

The provisional FPDs...are usually constructed on nonengaging, screw-retained titanium temporary abutments.

AESTHETICS70

4. This is the stage of reproductionof the fit surface of the provisional FPD.The use of a silicone impression puttyhas proven to be the most accuratemethod. A laboratory im pression putty(Provil Novo Fast Set [Heraeus Kulzer])was mixed according to the manufac-turer’s instructions and the FPD/replicacombination pushed into it and, whilestill soft, the putty was adapted ontothe gingival one third of the FPD(Figure 5a). It is advisable to keep thereplica end submerged in the puttyrather than allowing it to protrude

through it. It is also preferable to avoidcreases and folds within the puttyaround the FPD, as these will be subse-quently reproduced on the fit surface ofthe stent during manufacture. In turn,this could affect accurate seating of thestent prior to impression taking.

5. Once the putty had set, the pro-visional FPD was carefully un screwedand removed. Any thin excess of puttycan be cut away with a scalpel, but itis imperative that excessive height isnot removed. If in doubt, a pencil linecan be drawn on the provisional FPDto indicate the portion which relatesto the area that is located subgingival-ly and must be reproduced in the

stent at the next step (Figure 5b). 6. The previously splinted impres-

sion copings were then accurately re-fitted inside the silicone putty. It isadvisable to take a check-radiograph atthis stage to ensure accurate location.

7. The combination is now readyfor fabrication of the stent. Flowablelight-cured composite resin (such asVenus Flow [Heraeus Kulzer]) was used.To minimize polymerization shrinkage(and the potential in-built stresses thatcan lead to distortion and difficulty inseating the finalised stent), the compos-ite was initially incrementally appliedaround the copings and then light-cured. Sub se quent additions were

made and light-cured toward the mid-line (Figure 5c), with the final additionsbeing made across the midline. Sincethis area of unsupported compositeresin is vulnerable to fracture duringmanipulation, it is advisable to rein-force it with the addition of a furtherbulk of composite resin.

8. The impression stent could nowbe removed from the putty. Excess com-posite resin “flash,” along any protrud-ing sharp “spikes” created by any creas-es or voids within the putty, wastrimmed away (Figure 6a). The stentwas then fitted in the mouth (Figure6b). If it was fabricated at chairside,rather than be tween visits, a certain

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The Creation of an Emergence Profile...continued from page 68

Figures 4a to 4d. The sequence of steps with the splinted impression copings.

a b c d

Figures 6a to 6c. The splint, upon removal from the silicone putty after trimming excess

flash (a). Shown in position in the mouth (b); the check-radiograph (c).

a b c

Figures 5a to 5d. The sequence of steps taken with the silicone putty.

a b c d

Figures 8a to 8d. The emergence profile prior to impression taking (a), and the degree of accuracy of reproduction of the soft tissues on the initial working model (b). The model prior to

efinement with a round diamond bur (c), and the final working model (d).

a b c d

Figure 7. The final impression, upon

removal from the mouth.

Adjustments arerarely requiredto the emergenceprofile of the porcelain....

AESTHETICS

degree of collapse of the emergence pro-file will be encountered, taking up to 10minutes for any tissue blanching to dis-appear. For this reason, it is preferable toreach Step 5 at a previous visit and com-plete stent fabrication at leisure, beforethe impression appointment. A check-radiograph may be taken at this stage toensure that the stent and impressioncopings are fully seated (Figure 6c).

9. If the stent is correctly seated, thefinal impression can now be made; inthis case a polyether impression materi-al (Impregum Penta, 6 Minute Hard [3MESPE]) was used in a custom impressiontray. The authors prefer this hard im -pression material as it ensures that thestent remains within the impressionupon removal. Once the impressionmaterial had set, the impression cop-ings were un screwed and the tray wasremoved from the mouth (Figure 7).

10. The degree of accuracy of theduplication technique is seen whencomparing the clinical picture (Figure8a) with that seen in the working soft-tissue model (Figure 8b). At this stage,final minor modifications to the emer-gence profile can be carried out with adiamond bur (Figure 8c). Care must betaken not to undermine the buccal tis-sue support, which could lead to analteration in buccal tissue height intra-orally. The refined emergence profile isshown after trimming (Figure 8d).

As shown in part 1 of this series,the access cavities to the screws are ide-ally located in the palatal area of theprovisional screw-retained prosthesis.This access could therefore easily bereproduced within the final prosthesiswithout undermining the integrity ofthe surrounding porcelain.

In this case, the decision was madeto provide a screw-retained zirconiumoxide fixed prosthesis as the final de -sign (Figures 9a and 9b). However, inthose cases where the access cavities arelocated in the incisal (or even the buccalareas) of the provisional screw-retainedprosthesis, this access could not reason-ably be reproduced within the final por -celain prosthesis without compromis-ing the aesthetics and integrity of theporcelain. These cases are more success-fully restored if screw-retained abut-ments are provided, and the definitiveFPD is designed to be cemented ratherthan screw-retained. Although angledabutments can be used to palatally re -align the access cavities to the screwswithin the FPD, invariably the metalcollar of the abutments will shinethrough the buccal gingiva of the abut-ments, or worse, show at or above thegingival margin.

If the final design selected is

cement-retained, the authors havefound that it is preferable for the tech-nician to work on a solid as well a soft-tissue model in order to accuratelyreproduce the “porcelain” emergenceprofile. If refinements were made tothe emergence profile on the initialworking model, these have to bereproduced. It is, therefore, advisableto take a new impression of thismodel. Impression copings should befitted and splinted together, and a con-ventional impression taken in thecustom tray. The “bounce” encoun-tered when working on a soft-tissuemodel is rarely an issue when thedefinitive FPD is screw-retained.However, when the design is cement-retained, this “bounce,” and unwant-ed uncontrollable movement, couldlead to discrepancies in the fit surfaceof the final restoration.

The preoperative presentation isshown in Figure 10a. The minor mod-ifications to the working modelallowed space for the slightly roundedpapillae (that were visible at the pro-visional stage) to fall into place andprovide a more pleasing aestheticresult. The passive yet supportive fitof the final bridge (Figure 10b) fabri-cated around the created emergence

profile clearly improved the finalappearance of this case. If the tech-nique is accurately carried out, it isunlikely that multiple trial fits will berequired. Adjustments are rarely re -quired to the emergence profile of theporcelain, and they are usually associ-ated with refinement of the occlusionand shade matching. The aestheticimprovement achieved in the soft tis-sues around the lateral incisors is self-evident.

The healthy appearance of the gin-gival tissues was obvious upon re movalof the restoration one month after theinitial delivery (Figure 11). The com-pleted FPD is shown in Figure 12.

CONCLUSIONThe case, as presented in parts 1 and 2of this article series, demonstrates acombination of techniques which canbe used to predictably provide anexcellent aesthetic result with short-span implant-supported FPDs in highlip-line cases. If followed as outlined,it is a straightforward method of accu-rately reproducing the emergenceprofile created by both a provisionalFPD prior to implant placement and acarefully adapted provisional screw-retained restoration or cemented FPD

on screw-retained abutments. Timespent fabricating the stent not onlyreduces the need for numerous timeconsuming and frustrating trial fits, italso improves tissue stability; disrup-tion of the tissue attachment isknown to be damaging.1 Fabricationof the stent can ideally be undertakenby ancillary staff between patient vis-its, further reducing clinical time. Thenatural fit against the matured tis-sues, which was refined in the provi-sional phase of treatment, can be easi-ly and predictably achieved, resultingin a highly aesthetic restoration.�

Acknowledgement Our sincere thanks to Mick Kedge forall his help and support in developingthis technique, and for all the techni-cal work done in the dental laboratory.

Reference 1. Abrahamsson I, Berglundh T, Lindhe J. The mucos-

al barrier following abutment dis/reconnection. An

experimental study in dogs. J Clin Periodontol.1997;24:568-572.

Dr. Bereznicki graduated from Edinburgh Den -

tal Hospital and School in 1976. He moved to

London and entered general practice and start-

ed his own private practice in Queens gate,

London, in 1982. Recently, he has joined the

Dawood & Tanner Dental Practice in London as

a member of the restorative team. His area of

special interest is aesthetic dentistry, and in

particular the creation and duplication of the

created emergence profile in conventional and

implant retained crown and bridgework. He can

be reached via e-mail at tbereznicki@google-

mail.com.

Disclosure: Dr. Bereznicki occasionally lecturesand demonstrates for Nobel Biocare.

Dr. Dawood is a registered specialist in peri-

odontology and prosthodontics, and has hon-

orary attachments to the department of maxillo-

facial surgery at St. Bartholomew’s and The

Royal London Hospital Trust, and University

College Hospital, London. Dr. Dawood joined a

long established restorative dental practice in

1987, which he later took over with his partner,

Dr. Susan Tanner. His time has been devoted

almost entirely to dental implants, imaging, and

surgical planning. Dr. Dawood is also the

founder and clinical director of Cavendish

Imaging (cavendishimaging.com), which pro-

vides imaging, computer-planned surgical solu-

tions, and rapid prototype models, guides, and

craniofacial implants for implant and maxillofa-

cial surgeons, and hospital departments around

the United Kingdom. He operates a center for

postgraduate education, and hosts regular

meetings and seminars from the Cavendish

Imaging premises in London, Oxford, and

Birmingham, UK. Dr. Dawood lectures extensive-

ly abroad on topics related to imaging, dental

implants, and restorative dentistry. He can be

reached at info@dawoodandtanner.co.uk.

Disclosure: Dr. Dawood occasionally lecturesand demonstrates for Nobel Biocare.

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Other articles linked in this series can befound on dentistrytoday.com

Figures 9a and 9b. The definitive zirconium oxide fixed partial denture (FPD).

a b

Figures 10a and 10b. The clinical picture at the start of treatment (a), and on the day of the FPD

fitting (b).

a b

Figure 11. The soft tissues; one month after

initial FPD placement.

Figure 12. Close-up view of the completed

case, showing the excellent and predictable

aesthetic outcome.