feldspathic.pdf

32 eLABORATE March/April 2010

The Feldspathic/Refractory veneer is one of theoldest techniques practised in dental tech-nology and is still widely used in today’s

increasingly metal-free world.The advancement of CAD/CAM technology and

the development of new materials has enabled aconsistent, predictable aesthetically pleasing result.Having said that, this old veneering technique couldalso consistently deliver aesthetically pleasingresults, due to its translucency and the control of thecolour of the porcelain itself.

Traditionally, PFM porcelain has been used for thefabrication of the restorations, however, have youthought about using zirconia porcelains instead?

In general, modern zirconia porcelain delivers adenser, stronger result without shrinkage cracks andit is easier to achieve better aesthetics. This is due tothe variety of ready-made porcelains available innewer zirconia porcelain kits compared to tradi-tional PFM porcelains that require mixing manydifferent colours to achieve a decent result.

It also opens up more opportunities for materialchoice. For example, when we work on a combina-tion case - veneers with zirconia crowns - if we areable to use the same zirconia porcelain for the felds-pathic/refractory veneers, then we can use the sameporcelain throughout the restorations which wouldprovide a more consistent, accurate result in thecolour matching and material wear that affects thelongevity of the restorations.

In this article, I’d like to present an example of afeldspathic/refractory veneer technique using a zir-conia porcelain - Lava™ Ceram (3M ESPE™).

Case planningFigure 1 and 2 shows the pre-op condition of a malepatient in his late 20s. The main issue is themicrodont on the laterals as well as a reasonablyhigh smile line. The treatment plan is for crownlengthening on the four anterior teeth to reduce the gummy smile appearance, bleaching to increasethe brightness overall and a composite build-up on the incisal third of the canines to increase thelength incisally.

Figure 3 and 4 shows the result of crown length-ening and bleaching. There is a big improvementalready!

For the laterals, our goal is to build them out byincreasing the length and width to keep them in pro-portion. Only minimal preparation is required so asto preserve the existing enamel as much as possible.The existing colour is close to the desired finalresult, hence we should consider incorporating thestump shade colour (i.e. the natural colour frombeneath) into the final restorations.

Anterior guidance will be maintained withexisting dentition palatally, so the strength of thematerial is not a major concern in this case, hencewhy the feldspathic/refractory veneer is chosenover a pressable technique.

Fusion of modern and ancient: Feldspathic/refractory veneers using zirconia porcelain

By Yugo Hatai

“Traditionally, PFM porcelain

has been used for the fabrication of

refractory veneers,however, have you thought about using

zirconia porcelains instead?”

ceramic | TECHNIQUES

March/April 2010 eLABORATE 33

Fabrication of refractory diesUpon receipt of the impression, the techni-cian who completes the model work (Figure5) usually does not know if the case is to beprocessed with refractory veneers or thepressable technique (as most likely thematerial is chosen after the model work isdone), so the first pour might be processedas a pin/section model. That, however, willnot in any way negatively affect the result asthe stone die has to be sectioned anyway,either with or without pins (Figure 6). Themodel is then trimmed with a tapered bur(Figure 7) to a root shape, so that the die cancome on and off (as will be shown later in

this article). Adding a relocation groove isnecessary (Figure 8) to place the die accu-rately back onto the model later on.

The original dies should be kept sepa-rate after the initial duplication and shouldbe used to check the fit once the veneersare completed.

The trimmed stone dies have to be dupli-cated with a high quality silicon material(Figure 9). Deguform (DeguDent, DentsplyAustralia) is recommended for a consis-tent, precise and accurate result. We willnow refer to this duplication mould beingthe Master Duplication, as this will be usedagain later in this article.

Debubbliser is sprayed (Figure 10) andthen stone dies poured (Figure 11). Onceset, two coats of spacer is painted (0.5 -1mm away from the margin) (Figure 12)prior to the second duplication of the dies(Figure 13).

Now here is the million dollar question:why is it that we don’t use zirconia porce-lain for feldspathic/refractory veneers? Itis because unless you use a special refrac-tory die material, you simply cannot get aconsistent result. A lot of sweat and tearshas been put into testing and researchingand finally, here is a solution and such asimple one too!

Figure 1. Pre-op Smile. Figure 2. Pre-op – Retracted View.

Figure 3. Smile after bleaching and crown lengthening. Figure 4. Retracted View after bleaching and crown lengthening.

Figure 5. Working Model. Figure 6. Sectioned Dies of the prep.


Figure 14 shows the answer. It’s arefractory material especially made forzirconia porcelain called Nori-Vest Zirconia from Noritake (Alphabond Australia), and it works very well

with a zirconia porcelain like Lava Ceram.Debubbliser is sprayed (Figure 15) and

the refractory material is poured (Figure16). Once set, the margin is marked with arefractory pen so the marking doesn’t burn

off (Figure 17) and a hole needs to be drilledon the bottom of the dies (Figure 18) so itcan be stabilized on a firing tray. Finally,degassing takes place (Figure 19) and therefractory dies are complete (Figure 20).

Figure 7. Shaping the dies with a tapered bur.

Figure 8. Completed trimmed dies withrelocation groove.

Figure 9. Initial Duplication of the dies.

Figure 10. Applying debubbliser to avoidpotential bubbles.

Figure 11. Pouring Stone into the MasterDuplication.

Figure 12. Applying Spacer onto the duplicated dies.

Figure 13. 2nd Duplication using the dieswith spacer.

Figure 14. Nori-Vest Zirconia - Refractory Die Material.

Figure 15. Applying debubbliser on the2nd duplicated silicon mould.

Figure 16. Pouring the refractory material.

Figure 17. Marking the margin with re-fractory pen.

Figure 18. Creating a bur hole for stabili-sation of the dies on firing tray.

Figure 19. Degassing of the refractory dies. Figure 20. Completed Refractory Dies.

March/April 2010 eLABORATE 35

Fabrication of master modelThe master model for build up is next cre-ated by pouring another stone die from theMaster Duplication (Figure 21). Once set,a thin layer of wax is applied to all areas(Figure 22) apart from the area that goesback into the impression (everythingabove the margin except the contactpoints). It is important to ensure that thelayer of wax is thin enough around therelocation grooves so that it will not be too

loose when we place the refractory dies onthe completed model later on.

The wax coated dies are placed back onthe impression and secured with wires andsticky wax (Figure 23) so that it will notmove during vibration when the stone ispoured (Figure 24). Ensure the bottom ofthe stone dies are exposed (Figure 25), asthe pour has to be done in two steps for anaccurate result.

Once the stone is set and the pins and

sticky wax removed, denture wax is placed(about 3-5mm in height) onto the exposedbottom of the stone dies (Figure 26) so weare able to locate their position easily (Figure28) after the second pour (Figure 27).

The denture wax is then steam cleanedand with some soft tapping through theexposed hole, the dies should be easily sepa-rated from the master model. The refractorydies can then be inserted onto the model(Figure 30) instead of stone dies (Figure 29).

Figure 21. 2nd set of stone dies to bepoured using Master Duplication.

Figure 22. Applying denture wax on thestone dies as a separator.

Figure 23. Securing the dies in the im-pression using sticky wax and wire.

Figure 24. Pouring 1st layer of stone. Figure 25. Showing the uncovered die heads.

Figure 26. Applying denture wax after removal of sticky wax and wire.

Figure 27. Pouring 2nd layer of stone.

Figure 29. Completed Master Model with the original stone dies. Figure 30. Completed Master Model with the refractory dies.

Figure 28. Completed Master Model showing exposed denture wax.



A little trick for better visualization of the final shape is that part of the wax up can be done on the stone dies, then akey is taken as a reference, then the diesare switched back onto the refractory diesand the same key is used during the buildup as a guide. As you may know, anythingwe can use to achieve a better resultalways helps.

Shade selectionColour matching to the natural dentition isa challenge for any ceramist. Shade takingface to face with the patient has tradition-ally been the way we have ascertained thecorrect colour from which to build therestorations. However, these days thequality of digital cameras has becomeexcellent and with careful interpretationbased on experience, it is possible tomatch the colour from the digital images.This also provides more opportunities - agood quality digital camera is a great com-munication tool that allows information tobe sent via email worldwide and withinseconds and if the ceramist is able tomatch the colour without ever seeing thepatient, it means the laboratory suddenlyopens up to a much broader client base. Infact, this case was completed without everseeing the patient and the colour matching

was achieved with only two photos(Figure 31 and Figure 32).

For this case, the colour of dentin on thecentrals is lighter than the B1 VITAPANClassical shade guide and these are bleachedteeth, so we should consider increasingboth the value of dentin shade from B1 aswell as the enamel. There is more of an A(reddish-orange) colour within instead ofB (yellow), so A1 dentin mixed with somebleach coloured dentin (i.e. W3) would besuitable. For the enamel, natural colouredporcelain (Mother of Pearl colour - N1 andN3) with Enamel porcelain (E2) would besuitable to achieve a high value enamelwith a high translucent appearance.

For the cervical, simply CI2 would besuitable (Central - 1 - CI1, Lateral - 2 - CI2and Canine - 3 - CI3) - this is a simpledecision with readymade porcelain avail-able from the kit!

It is important to build up the case usingyour imagination prior to the actual buildup so you know where you are heading.The colour has to be placed in the rightposition with precisely the rightdepth/layer to match the colour during thebuild up of the shape you are after.

It is very important to set your goalsfirst before you ever start building your porcelain.

Wash firingThe initial wash firing onto the refractorydies is such an important step for a smoothporcelain build up.

By covering the surface with a thinlayer of porcelain to start with, it will prevent the layered porcelain from dryingout during the dentin and enamel build up. The refractory material absorbs a great amount of moisture which couldcause some micro bubbling within therestoration, so it is essential to maintainthe moisture during the build up. It is recommended to use Ducera® Lay Saturation Fluid from DeguDent (Figure33) to saturate the dies prior to the build up. Place the liquid into a small container,dip the dies, leave it for approximately 5 minutes and then you’re ready to continue.

It is important to do a wash firingbeyond the margin (at least 1-2mm over) for a better fit. Some FluorescentTransparent - Opal porcelain is useful for the wash firing (i.e. Lava Ceram ICE 2) (Figure 34). This provides you with the right amount of fluorescencein the right place and a warm reddishtranslucent effect from beneath, whichhelps towards achieving a natural looking result.

Figure 31. Shade photos with B1 and B2 Vita Classical Shade Guide. Figure 32. Shade photos with B1 and B2 Vita Classical Shade Guide.

Figure 34. Lava Ceram - ICE 2 - Fluorescent Transparent - Opal.Figure 33. Ducera® Lay Saturation Fluid(DeguDent GmbH).


Final restorationsFigure 35 and Figure 36 show the final result of the fabricatedveneers. It is an aesthetically pleasing natural looking result. The restorations blend into the surrounding natural dentition,being undetectable.

There are some check points to go through to achieve a naturallooking result which I detail next.

Figure 37 shows the black and white image. It defines the valuefar more easily than coloured photos can. As you can see, the cen-trals are higher in value compared to the rest of the arch and thisis quite often the case in an all natural dentition.

Figure 38 is an example of a natural dentition showing the dif-

ference in chroma of the centrals, laterals and canines. Thechroma is different in those three teeth and quite often, you seeadditional reddish chroma in the laterals and yellowish chroma incanines, from the base shade in the arch. As a result, they appearlower in value compared to the centrals in general.

Breaking up the chroma keeps your eyes from not focusing onone particular area or point and that makes the restorations unde-tectable (have a look at a nice photo of natural dentition. Yourfocus won’t stay in one area it moves around. Do you notice that?It’s because they are irregular and unbalanced, but perfectly inproportion in shape as well as with colour).

Figure 39 and Figure 40 show the effect of the difference in

Figure 35. Post-op Smile. Figure 36. Post-op retracted view.

Figure 37. Black and White image of Post-op retracted view. Figure 38. An example of Natural Dentition.

Figure 39. Lateral view of Post-op - Right. Figure 40. Lateral view of Post-op - Left.



chroma. This is particularly importantwhen you are working on a larger case toavoid creating a monochromatic uncharac-terized restoration. These subtle differencesare very effective in a positive way. Figure41 shows the greatest difference in chromawith the teeth appearing healthy and nat-ural despite the difference in chroma. Thegingival level of the 22 is slightly higherthan the ideal position hence some subtleroot surface was created within the restora-tion to keep them in proportion.

Figure 42 shows the mid third of thedentition. This is probably the mostuncharacterized and uniform colouredarea of the tooth itself. Keeping this areasimple will provide a clean look yet nat-ural appearance, so less is more!

Figure 43 shows the incisal effect.Unless being specified, the irregularincisal edge of 11 is considered slightlytoo extreme, but it is a natural dentitionwith this case so some extra effect isadded on the 12. It’s right next to 11 so itis not that noticeable from the patient’spoint of view, yet provides a natural effect.

22 has the opposite effect in shape, it isfairly nice and smooth, matching with 21and 23. The shape of the laterals are quiteirregular in natural dentition, so creatingdifferent shaped laterals can appear naturaland helps breaks up the smile in a positiveway. In this case, the area available on thelaterals were different i.e. the space avail-able for 12 was larger than 22, hence thedistal of 22 was rotated protrusively tomake them appear slightly wider, thuskeeping them in proportion. In Figure 39and Figure 40, the size of the laterals seemmostly the same, but in Figure 35 andFigure 36, the 22 appears slightly widerthan the 12. Again, this will not be notice-able until someone points it out and again,it is a positive step towards a natural effect.

Figure 44 and Figure 45 show theBefore and After. What a difference!

AcknowledgementsI’d like to thank Dr Tony Rotondo who is aProsthodontist based in Brisbane, Australiafor his outstanding skill and knowledge onboth the clinical and technical perspectives

and also for the contribution of the clinicalphotographs in this article.

I’d also like to thank my wonderful dedicated team at Smile by Yugo for their assistance.

About the author Yugo Hatai is a master ceramist based inSydney who has enjoyed numerous acco-lades from many leading clinicians for hisattention to detail and ability to re-createa natural tooth. He was born in Japan in1978 and completed the dental techni-cians course from Amagasaki DentalCollege and was then registered as a dentaltechnician. He was later selected to furtherhis studies at Osaka University of DentistryHospital. He migrated to Australia in 2000and became a registered dental technicianin NSW in 2001. Since then, he hasattended many courses covering advanceddental studies. In 2008, Yugo establishedSmile by Yugo in Sydney’s Darlinghurst tocreate a space to meet his vision, thefusion of Fashion and Art into dentistry.For info, see www.smilebyyugo.com.au.

Figure 41. Cervical third Post-op.Figure 42. Body third Post-op.Figure 43. Incisal third Post-op.

Figure 44. Before. Figure 45. After.


References1. Pascal Magne, Urs Belser - Bonded PorcelainRestorations in the Anterior Dentition: A BiomimeticApproach - 2002 Quintessence.2. Yugo Hatai - Reproducing Nature Part 1 - Under-standing the shape, colour and composition of naturalteeth - eLABORATE Nov/Dec 2005.3. Yugo Hatai - Reproducing Nature Part 3 - Toothreplacement with root and colour matching using dig-ital photo - eLABORATE Nov/Dec 2006.4. Yugo Hatai - Reproducing Nature Part 4 - SmileDesign - eLABORATE May/June 2007.5. Yugo Hatai - Reproducing Nature: Smile Design -LVI VISIONS Jan/Feb/Mar/Apr 2008.6. Yugo Hatai - Reproducing Nature: Understandingthe Composition of Natural Dentition - The EuropeanJournal of Esthetic Dentistry, Volume 3 Number 4Winter 2008.

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