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116 oralhealth April 2005

As patients become increasing-ly aware of the esthetic po-tential through cosmetic den-

tistry, there is an increasingdemand for smile makeovers withporcelain. In our efforts to createbeautiful smiles, we tend to focuson tooth color, shape, proportionand alignment as we are bom-barded with restorative choices.

However our efforts for an idealrestorative outcome will fall shortif we are distracted from the larger

picture to focus on teeth andsomewhat neglect the impor-tance of gingival health and con-tour. The goal of modern esthet-ic dentistry is to achieve bothwhite and pink esthetics.1

White esthetics refers to nat-ural dentition or tooth coloredrestorations. Pink Estheticsrefers to the surrounding softtissues (Figs. 1 & 2).

Every dentist has experienced

the disappointment of a cosmeticcase that starts out beautifullythen is marred by receding orinflamed tissue. The question ishow do we increase our chancesfor optimal tissue response andlong term health? Our focus inthis article for this broad ques-tion will be our microscope cen-tered approach for porcelain pre-cision and the role of high levelmagnification in assisting idealgingival esthetics.

HOW MUCH MAGNIFICATION ISENOUGH MAGNIFICATION?Today most restorations are stillperformed with little or no magni-fication. However, critical analy-sis of some esthetic compromiseswill show progressive decline ofgingival color from ideal salmonpink to bluish purple typical ofchronic mild inflammation. In ourpractice we are surprised at thenumber of patients who report tous for re-treatment of cases be-cause of mildly red or purple gin-

giva (Fig. 3). Such requests areevidence that non-ideal tissueresponses impact patient accep-tance of cases much more thandentists would have thought. Wemay be underestimating the im-portance of pink esthetics tooverall treatment success.

Numerous studies have shownthat gingival and subgingivalmarginal discrepancies greaterthan 50 microns cause untowardtissue response with increased

crevicular fluid flow, alteredbacterial flora, and poor esthet-ics.2-5 Carr has demonstratedthat the unaided human eye

FIGURE 1Microscope Enhanced EstheticDentistry. Perfect gingival health andesthetics become a reality with micro-scopically adapted and highly polishedporcelain.

FIGURE 2Equa-gingival finish line withMicroscope Assisted Precision. Pressedceramics by Peggy J. Parker C.D.T. ofDTI / Twin Lakes. Post-operative photo-graph shows optimum tissue health. Suchesthetic results were rare until we incor-porated microscopic visualization forpreparation, impression, temporization,sculpting of finish lines, and seating.

Optimizing Gingival Esthetics:A Microscopic PerspectiveDavid J. Clark, DDS and Jihyon Kim, DDS


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FIGURE 9Unacceptable margin esthet-ics. Dentists who experience these typesof postoperative results often becamegun-shy and either stop providingesthetic treatment or start burying fin-ish lines deep in the sulcus. The bettersolution is Microscope Assisted Pre-cision in esthetics.

FIGURES 10A & BDepict the pre and post-operative full view of the case shown athigh magnification in Figures 1 and 2.

FIGURE 3Although the two porcelaincrowns on the central incisors violate theGolden Rule of proportion, this patientpresented for re-treatment because ofpoor gingival esthetics, not because ofporcelain esthetics. A very large percentof esthetic treatments done with low orno magnification create similar tissueresponses.

FIGURE 4Oculars (loupes) rely on con-vergent vision that essentially requiresan overlap of two images. This form ofmagnification creates increasing prob-lems and eye strain as power increases.The clinical microscope utilizes a morerefined optical system.

FIGURE 5Features 8x convergent mag-nification with loupes and a representa-tion of the two images that your brainreceives as you begin to focus.

FIGURE 6Shows a common occurrenceof incomplete merging of images. Bothimages demonstrate the visual noise orblurry periphery of loupes optics.

FIGURE 7Represents 24x Infinity Cor-rected or parallel optics. There is no eyestrain and no visual noise. Loupes magni-fication at 8x and above becomes excru-ciating for most clinicians, the microscopeis a superior and healthier choice.

FIGURE 8Typical undulating CEJ con-tour on a mandibular canine. There is astark difference in the appearance ofenamel and dentin at 10x magnifica-tion that coupled with an appreciationof dental anatomy, will guide moreappropriate margin placement.

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April 2005 oralhealth 117


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cannot distinguish two discretelines closer than 200 microns.6

Not surprisingly many restora-tive margins have average dis-

crepancies of 200 microns andsadly we often see gross dis-crepancies much greater in fail-ing restorations.

Carr has also demonstratedthat 4x magnification is re-quired for the human eye to dis-tinguish two black lines 50microns apart. However, 4xloupes may not be sufficient inconsideration of three impor-tant issues.

1) Less visual contrast is avail-able to distinguish a tooth col-ored restorative margin from a

tooth finish line than twoblack lines separated by white.Therefore 4x magnificationmay be insufficient in porce-lain or resin restorations. Infact many clinicians who takeour microscope courses com-ment that they need at least10x magnification to discernthe marginal integrity of por-

celain laminates.

2) Magnification of 4x or greaterrequire better quality light be-yond what can be provided by atraditional operatory light. Athigher magnifications a micro-scope makes more sense thanadding a headlamp to loupesthat have insufficient power.

3) Magnification needs can rou-tinely escalate to 16x or 24x

FIGURE 12An extracted tooth is fea-tured in figures 12-14. The tooth wasremoved because of hopeless endo-restorative failure after one year. In fig-ure 12, magnification at 24x revealscomposite cement that was left nearcrown margin. The discoloration createsthe illusion that the material is calculus,not cement. The composite cement waslikely a different color one year earlier(when the crown was seated by the pre-vious dentist). The new compositecements have more natural color,increased translucency, and higherbond strengths than previous cements.This has generated a new problem ofwidespread residual cement causingpoor tissue health and esthetics.

FIGURE 13Shows a plus margin inprofile. This very common situation willnearly always result in extremely poorgingival health and esthetics. Most clini-cians and technicians are in absolutedisbelief that their porcelain contourscould look like this, but the reality is thatthis problem is present on most porce-lain restorations in select marginalareas. High magnification and therolling profile technique for analysisshed light on the dilemma.

FIGURE 14Shows a different area ofthe same tooth with a different set ofproblems. The tooth has been sectioned

to highlight both a sub and shortporcelain margin. The finish line wasalso placed on composite, not toothstructure. This is a common problem. Allresin buildup materials (tooth colored ornot) in deep subgingival areas demandextremely high levels of magnificationand illumination to prepare adequately.

FIGURE 11Depicted here is a co-obser-vation tube allowing us to simultaneous-ly view the nuances of a case. Involvingthe ceramist more directly in patientcare leads to better communication ofinformation and a passionate commit-ment of the technical team. We foundthat monetary compensation was lesseffective than pride in generating the

commitment required for microscopeenhanced dentistry.


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when working with challengingcircumstances such as posteri-or areas, difficult isolation, orindirect vision.

Thus in order to achieve mar-ginal precision with consistencyin porcelain or resin restorations,magnification of 8x or higher isrecommended. Such magnifica-tion and light requirements are

difficult to attain with loupes anda separate light source.

FUNDAMENTALS OFCLINICAL MAGNIFICATIONThe operating microscope offersnot just higher magnificationthan oculars (loupes) but bettermagnification. Oculars havebeen very helpful and mayalways have a role in dentistry,but the optics is crude when com-pared to the Infinity Corrected

Optics of a stereoscopic micro-scope (Figs. 4-7). When combinedwith the shadowless coaxial lightsource, they transform the clini-cians potential for accuracy innearly every aspect in the differ-ent disciplines in dentistry.

Most importantly, increasinglevels of magnification produce asquared, not linear relationship to

visual acuity. In other words, 10xmagnification allows the humanretina to acquire 100 times moreinformation and 20x allows 400times the visual information.

PRINCIPLES OF TOOTH PREPARATIONAND PORCELAIN MARGINS FORGINGIVAL ESTHETICSThe enormous advantage theoperating microscope offers isability for acute visual inspec-tion. This precision along with

skill and recognition enables usto readily identify the cemento-

enamel junction (CEJ), createmore appropriate finish lines forthe rigors of porcelain adapta-tion, and eliminate noxious tis-sue irritants.

One of the most common offens-es to delicate gingival architectureis when the clinician fails to followthe undulating contour (Fig. 8) ofthe CEJ and instead creates a flatmargin from facial to lingual. Thisis often exacerbated or initiated

by rubber dam placement, whichflattens the papillae and leads tomisinterpretation of the appropri-ate placement for the interproxi-mal finish line.

Thus begins a series of mis-takes. The interproximal marginis cut too deep, followed by ag-gressive tissue retraction. Whentwo approximating teeth are pre-pared in this manner and the tis-sue is subsequently retracted

FIGURE 16We utilize a brownie pointin a high-speed handpiece at 24x totrim finish lines with less than 0.75 mmof apical impression profile. Othermodalities can cause chunks of the mar-ginal stone to break away with theexcess stone.

Table 1

Microscope protocol for porcelain margin evaluation

Sub PlusShort Long

Under-Contoured Emergence Profile Rounded Emergence Profile

Table 2

Parameters to be combined with factors from Table 1to maximize the total potential for tissue health

1) Residual cement and calculus apical to finish lines

2) Root roughness from errant bur movements

3) Micro-roughness and porosities of porcelain

4) Microleakage

FIGURES 15A & BMicroscopic visualization affords the ability to achieve consistentyet delicate tissue retraction. Heavy, aggressive retraction (A) can give way to amore refined approach (B).


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with cord, electrosurgery or abla-tion, the papilla is often obliterat-ed. The papilla sometimes returnsbut sometimes not.

In a classic study, two interden-tal papillae were excised from16dental students.7 Of the 32 speci-mens,22 papillae did not return tothe original shape. This 69 percentattrition rate should serve as awakeup call. The dreaded blacktriangle usually ensues, whichcan be both an esthetic and func-tional nightmare. Exotic regenera-tive techniques or bulky porcelaincontours are a poor substitute forconservative tooth preparation

and delicate micro-manipulationof tissues.

With the benefit of high-levelmagnification, a series of delicateand physiologically appropriatesteps can occur.

MICROSCOPE ASSISTED PRECISIONAND ENAMEL FINISH LINESThe fear of marginal esthetics(Fig. 9) has driven clinicians tobury their margins, creating a

whole new set of problems,which include pulpal, periodon-tal and microleakage issues.

Whenever possible a porce-lain-enamel marginal inter-face is the goal in bondedporcelain restoration (Figs. 1& 2). This will place the finish

line either slightly supragingi-val, equa-gingival or slightlysubgingival. In cases of gingivalrecession, it is preferable to coverexposed dentin with gingiva (in

lieu of porcelain or composite)via procedures such as connec-tive tissue grafts.

Periodontists using high-levelmagnification have demonstratedpredictable and breathtaking rootcoverage. Afterwards, a porcelainmargin can be placed on enamel,nestled neatly near robust gingiva.

The Contact Lens Effect hasbecome a popular term. One

interpretation relates to the abili-ty to create invisible porcelainmargins that need not be hidden.We see that the optimal combina-tion is 1) translucent porcelain, 2)a translucent luting agent, and 3)translucent tooth structure, pre-ferably enamel. Once the finishline for a porcelain laminate isplaced on dentin, the contact lenseffect loses some of its magicbecause dentin is more opaquethan enamel.

Dentin margins pose other diffi-culties as draw becomes more of aproblem, the pulp is further trau-matized, and a strong enamel bondis sacrificed for a tenuous dentinbond.Maintaining a minimum of a750 micron distance from the CEJduring preparation requires highlevels of magnification.

MARGINAL PRECISIONOF PORCELAIN

Volumes of information arebandied about when debating

which porcelain has the best mar-ginal accuracy. In the end, most ofthese arguments are moot be-cause other factors create discrep-ancies that are significantly morecritical. A poll done by CRA re-

vealed that 90 percent of impres-sions received in U.S. laboratoriescontained portions that did notcapture the finish lines. In thesecases we will see gross inaccura-cies that will lead to micro leak-age and poor tissue response.

Additionally, microscopic in-spection reveals that many res-torations are not fully seated dur-ing cementation. The culprit isoften improper contacts, hardly amicroscopic issue, but floss aloneis not enough to make a properassessment. High magnificationprovides complete visual informa-tion required to trouble shoot allcauses of incomplete seating,including a lifting contact. Once

FIGURES 18A, B & CIn (A) the porcelain laminate is not fully seated. Dehydration andmagnification (B) reveal residual luting composite that was used to retain the inter-im laminates. After discovery and removal of the obstacle, full seating of the lami-nate to within 25 microns is observed (C).

FIGURE 17The rolling profile techniquefor evaluation and sculpting of porce-lain interfaces. Coaching our ceramiststo see and think in a three dimensionalmicroscopic way required more than aquick phone call. Hands on teaching inour office with microscopes and a videofeed to monitors have proven invalu-able. In addition to the dramaticimprovement in the accuracy of theceramists work, we continue to do achairside microscopic analysis andsculpting of porcelain before seating.


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is reduced postoperative discomfort for patients.10

TECHNICIANS CAN BE THE MISSING LINKMicroscope dentists, enjoying newfound precisionwith preparations and impressions, may wellbecome frustrated with ceramists whose workbecomes the weak link in precision. We tried many

labs and toiled with ceramists who, though theyhad lab microscopes, were unwilling to treat ourcases with special care. Many labs have micro-scopes with poor optics, dim light, filthy lenses,and are in such a state of neglect that they arenearly worthless.

One of the most challenging steps in the questfor precision in porcelain is the visual challenge ofminimal contrast. In addition to the stark colorcontrast it offers, gold casts a useful shadow when

viewed directly on the tooth or die. Unfortunately,most technicians use the visual approach thatworks well with gold when analyzing porcelain.While gold may be analyzed by looking directly atthe margin/die interface, we have found thatporcelain must be evaluated in profile.

Together with our ceramists we have created aprotocol to consistently produce porcelain andporcelain fused to metal restorations that hold upto the scrutiny of 16x magnification. One compo-nent of the system is the three die protocol thatgives us a virgin die for evaluation and final sculpt-ing of the finish lines. In order to implement this

new protocol, Chuck Rickabaugh at Twin Lakes/DTI actually created a lab within a lab. With theright team, it can be done!

GINGIVAL PORCELAIN FINISHING BURS AREUNNECESSARY IN A MICROSCOPE-CENTERED APPROACHMainstream dentistry is moving toward the cre-ation of two margins, a porcelain and a compositemargin. Porcelain that is several hundred micronsoff in both horizontal and vertical axis are theoret-ically sealed by the new super viscous compositecements. Margins that are accessible are some-times dressed down with finishing burs. These

protocols are the standard of care but when viewedunder the microscope we see the following:

The high luster of porcelain cannot be fully re-established near the sulcus with the dressingdown of porcelain margins. Additionally the rootis often scarred and the gingiva mutilated,

The cement margin is chalky and becomes evencoarser over time,

The composite margins are prone to micro-leakage,

The new super viscous cements are creating everwidening marginal gaps as the crown or veneercannot be wrestled fully to place.

The concept is different with the microscope-cen-tered approach taught at Precision Esthetics North-west and Newport Coast Oral Facial Institute. No

gingival finishing burs are used. Instead with micro-scope precision, the excess luting cement is scis-sored away cleanly as the ultra-precise laminate isseated. A surgical #12 blade in a Hartzell roundscalpel handle cleaves away excess luting composite.There is only one margin, a laboratory or chair sidepre-sculpted and pre-polished porcelain margin.

CHAIRSIDE MARGIN RECONTOURINGAND MICROSCOPE ENHANCED SEATINGThe final leg of our quest for microscopically idealesthetics demands another step. While waiting foranesthesia, we evaluate the three parameters ofmarginal integrity. The marginal interface andemergence angles are evaluated at 12x to 24x in pro-file while slowly rolling the die and porcelainrestoration 360 forwards and backward. Plus mar-gins and overly rounded emergence profiles are care-fully and quickly sculpted with a Brasseler #0301


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medium grit silicone polishingwheel (Fig. 19).

If the integrity of a die is in ques-tion, the patient is present for

verification. This versatile and in-expensive wheel appears to melt

the porcelain away without thechattering and potential micro-fractures from burs. Incredibly, italso leaves a very smooth finish.

Try-in, luting, and cement re-moval under the microscope is a

joyful experience. The microscopeenables us to visualize problemsinvisible under low or no magnifi-cation (Figs. 20-22). Better yet, arich array of clues will lead tosolutions so that the case can pro-ceed to success instead of startingover or compromising the finalresult.

CONCLUSIONReasonable restorative outcomescan be achieved with amalgamand gold with low or no magnifi-cation. In contrast, tooth coloredmaterials require much higherlevels of magnification for consis-tent success. Common clinical

magnification simply has not keptpace with dramatic changes inrestorative materials and patientexpectations. In spite of otheradvances in dentistry, marginalintegrity, emergence profile, andresistance to microleakage haveall taken a giant step backward.

Certainly, gifted clinicians ex-

ist who operate with little or nomagnification and do breathtak-ing esthetic dentistry. The micro-scope does not make one dentistbetter than another. Nonethe-less, many accomplished restora-tive dentists have embraced the

use of the microscope because itbrings greater predictability and

joy to their dentistry. Excellencein dentistry is a choice, and mag-nification can be a powerful assetin achieving it.

The testimony of doctors whouse the microscope daily in theirpractices confirms its value. Anoverwhelming majority affirmthat it has improved their clini-cal skill. The microscope, withinstantaneous magnificationfrom 2.5x to 24x, no visual noise,and shadowless coaxial light,offers the best means for achiev-ing complete visual informationin dentistry. It can nurture greatconfidence, healthier posture,and better and surer hands forthe clinician. In the end, theexcellent visual information themicroscope offers can help thedoctor to create more precise,

more healthful, and more esthet-ically pleasing dentistry. OH

Dr. David Clark founded the Acad-

emy of Microscope Enhanced Dent-

istry, an international association

formed to advance the science and

practice of microendodontics, micro-

periodontics, microprosthodontics and

microdentistry. He is a course director

at the Newport Coast Oral Facial Ins-

titute in Newport Beach, CA. He is co-

director of Precision Aesthetics North-

west in Tacoma WA. Dr. Clark main-

tains a microscope-centered restora-

tive practice in Tacoma, Washington

USA.

Dr. Jihyon Kim is a 1999 graduate

of the University of Washington

School of Dentistry. She is one of the

founding members of the Academy of

Miroscope Enhanced Dentistry.

Oral Health welcomes this original

article.

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Periodontal Aspects of cementation: materials, tech-

niques and their biologic reactions. Rev Belge Med

Dent. 1998;53(4):181-92.

3. Sorensen Se, Larsen IB, Jorgensen KD. Gingival and

alveolar bone reaction to marginal fit of subgingival

crown margins. Scand J Dent Res. 1986 Apr;

94(2):109-114.

4. Sorenson JA. A rationale for comparison of plaque-

retaining properties of crown systems. J Prosthet

Dent. 1989 Sep; 62(3); 264-9.

5. Lang NP, Kiel RA, Anderhalden K. Clinical and micro-

biological effects of subgingival restorations with over-

hanging or clinically perfect margins. J Clin Perio-

dontol. 1983 Nov; 10(6): 563-78.

6. Carr GB, Magnification and illumination in endodon-

tics. In: Hardin JF. Clarks Clinical Dentistry. Vol 4.New York, NY: Mosby:1998: 1-14.

7. Holmes CH. Morphology of the interdental papillae. J

Periodontol 1965;36:455-60.

8. Clark DJ. Microscope enhanced esthetic dentistry.

Dent Today; 2004 Nov; 23(11) 96-101

9. Clark DJ, Sheets CG, Paquette JM. Definitive diagno-

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