porcelain laminate veneers

8/18/2019 Porcelain Laminate Veneers

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Porcelain laminate veneersA. W. G. Walls, J. G. Steele and R. W. Wassell

British Dental Journal 2002;193:73–82


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Introduction

• Veneer : (GPT-8)- a thin sheet of material usually used as a finish

-a protective or ornamental facing-a superficial or attractive display in multiple layers,freuently termed a laminate veneer!

• Porcelain laminate veneer(GPT-8) - a thin "onded ceramic restoration that restores the

facial surface and part of the pro#imal surfaces ofteeth reuiring esthetic restoration


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Porcelain veneers are resin-"onded to the underlyingtooth and provide a conservative method of

improving appearance or modifying contour, $ithout resorting to a full coverage cro$n


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History

• Porcelain laminate veneers (P%V) $ere introducedinto dentistry as &olly$ood veneers "y Pincus('8)

• *ith the advent of efficient "onding of resins toenamel and dentine and the use of etched, coupledporcelain surfaces that aesthetically pleasing,dura"le and successful restorations can "e made


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• +ustom-made acrylic resin veneers naccepta"le levels of failure and marginal stain!

• .irect or indirect composite resin materials! .egradation of surface features and accretion of

surface stain $ith time


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• Porcelain veneers traditionally "een made fromaluminous or reinforced feldspathic porcelains /intered Porcelains Glass 0nfused +eramics +ast Glass +eramics &ot Pressed, 0n1ection 2oulded +eramics

2achined Glass +eramics 2achined .ensely /intered +eramics


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Indications

• 0mprove e#treme discolorations such as tetracyclinestaining, flourosis 3 devitali4ed teeth!

• 5epair chipped or fractured teeth!

• +losing of diastemas "et$een teeth!• To lengthen anterior teeth!

• 0mprove the appearance of rotated or malalignedteeth


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Contraindications

• 0f little or no enamel is present, full cro$n should "econsidered!

• +ertain tooth-to-tooth ha"its li6e "ru#ing orclenching, or other para-functional ha"its such aspencil che$ing or ice crushing!

• Teeth that e#hi"it severe cro$ding!• +ertain types of occlusal pro"lems such as +lass 000

3 end-to-end "ites


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Risk factors for veneer failure• 7onding onto pre-e#isting composite restorations• Placement "y an ine#perienced operator

• sing veneers to restore $orn or fractured teeth $here a com"ination of parafunction, large areas ofe#posed dentine and insufficient tooth tissue e#ist!

• Thermal changes and polymerisation contractionstresses $ill cause crac6ing of the veneer $hen theporcelain is thin and the luting composite thic6


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• 2inor chipping and crac6ing may "e smoothed or

repaired $ithout the need to remove the $hole veneer• .unne and 2illar reported that the incidence of

such repaira"le defects (8) $as similar to the

num"er of veneers reuiring total replacement('')

• This data is helpful in e#plaining to patients a"outthe longevity of the veneers

• 9lthough most patients remain satisfied a"outesthetics (8-') veneers are prone to staining atthe margins!


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Causes of staining of veneers

• 2icro lea6age at the cervical margin, especially $here located in aprismatic enamel or dentine

• *ear and su"margination of the luting composite,especially $ith an open margin

• 2arginal e#cess of luting composite


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Clinical Technique


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Aims of toot !re!aration• Provide some space into $hich the technician can "uild porcelain $ithout over-contouring the tooth

• Provide a finished preparation that is smooth and hasno sharp internal line-angles $hich $ould give areasof high stress concentration in the restoration

• 2aintain the preparation $ithin enamel $heneverpossi"le

• .efine a finish line to $hich the technician can $or6!


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"se of local anaestetic

• 2ay "e possi"le to prepare veneer preparations $ithout local anaesthetic

• /u"-gingival margin placement, inadvertent dentinee#posure and the unpleasant coldness from the $ater spray and aspirator usually ma6e its useadvisa"le


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#e!t of !re!aration

• Preparation should remain $ithin enamel• ;namel thic6ness varies from incisal edge to the

cervical margin

• Preparation depth $ill need to vary over the length ofthe tooth to avoid dentine e#posure

• !-!< mm at the facial gingival third, upto !=-'! mm

at the middle third and '!->!' mm at the incisal third!

• +lose to the gingival margin-!?mm• @or the "ul6 of the preparation- !A mm


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A 1 mm round diamond bur

being used to create deth mar!s on

the buccal sur"ace o" #$1 %11&

• .epth grooves tendency for the "ur to catch andrun into the groove, accentuating the groove

• .epth pits prepared on the surface of the tooth

using a 1mm diameter round "ur sun6 to half itsdiameter

• 5eduction should mimic natural curvature of toothto provide an even thic6ness of porcelain

• /hould "e done in at least t$o planes


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Incisal edge reduction

• @our "asic preparation designs-

Window Feather

Bevel Incisal overlap


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Window preparation

Ad'antage • 5etention of natural enamel over the incisal edge

Disad'antage• 0ncisal edge enamel $ea6ened "y the preparation!• 2argins of the veneer $ould "ecome vulnera"le if

there is incisal edge $ear

• 0ncisal lute may "ecome difficult to hide

Veneer is taken close to "ut notup to the incisal edge


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• 9uthors $ould not recommend the "uccal $indo$,as it is very difficult to mas6 the incisal finish line of

the restoration! 9s this style of restoration is used toimprove the appearance of teeth, the introduction ofan aesthetic defect $ould "e inappropriate


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Feather preparation

Ad'antage

• guidance on natural tooth is maintained

Disad'antage

• veneer is lia"le to "e fragile at the incisal edge• peelBsheer forces during protrusive guidance

•Veneer is taken up to the height ofthe incisal edge "ut edge is notreduced!


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Bevel preparation

Ad'antage

• more control over the incisal aesthetics

• positive seat during try in and luting of the veneer!• 2argin not in a position that $ill "e su"1ected to

direct shear forces e#cept in protrusion!Disad'antage

• more e#tensive reduction of tooth tissue

• A bucco-palatal bevel is preparedacross the full $idth of thepreparation and some reduction of

the incisal length of the tooth!


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Incisal overlap

• Provide a positive seat for luting $hilst involvingmore e#tensive tooth preparation!

• *ill modify the path of insertion of the veneer $hich $ill have to "e seated from the "uccalBincisaldirection rather than the "uccal alone!

• Incisal edge is reduced and veneer preparation e#tended ontothe palatal aspect of the

preparation!


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Incisal overlap

• +are needs to "e ta6en to ensure that anypro#imal $rap around of the preparationto$ards the gingival margin does not produce anundercut to the desired path of insertion for the veneer!

• 0t may "e necessary to rotate such veneers intoplace "y locating the incisal edge first thenrotating the cervical margin into position


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Ho$ to coose an incisal edge !re!aration

design%

• Hui et al demonstrated that veneers in $indo$preparations $ere "est a"le to resist incisal edge loading

and that an overlap design fractured at the lo$est loads!

• &o$ever, the magnitude of loading at $hich the overlapdesign veneers failed $as much greater than that

encountered clinically for such teeth

Hui K, Williams B, avis !, Holt "# A comparative assessment o$ thestrengths o$ porcelain veneers $or incisor teeth dependent on their designcharacteristics#

Br ent % &''&( 171: 51-55.


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• 9 clinical study "y 2ei1ering 9 + et al $as una"le todistinguish any difference in failure rate "et$een incisal

preparation designs after t$o and a half years of service

• 0f the operator intends to either improve the incisal edgeaesthetics or to increase the length of a tooth then either anoverlap or "evel design $ould "e the preparation of choice

2ei1ering 9 +, +reugers C &, 5oeters @ D, 2ulder D! /urvival of threetypes of veneer restorations in a clinical trial: a >!


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• 0f it $ere not necessary to e#tend the incisal edges,then it may "e possi"le to use featheredge design• Eperator has less control of incisal edge aesthetics

$ith this approach!

• Cord"o et al# report no $ailures but *+ incisalchipping at -years for veneers placed using afeather-edge design and ! to !< mm "uccal tooth

reduction!

Cord"o &, 5ygh-Thoresen C, &enaug T! linical per$ormanceo$ porcelain laminate veneers without incisal overlapping .-

/ear results! % ent &''0( 22: 342-345.


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• 0f the incisal edge is to "e modified then the lengthshould "e reduced "y some !


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Axial tooth reduction• .iamond "urs using an airotor or a speed

accelerating handpiece $ith a conventional motor!

• Parallel sided or tapered "ur $ith straight sidesrather than a flame shaped "ur

• 9 torpedo shaped "ur can "e used to produce "oththe a#ial reduction and the gingival finish line

• 9 round end taper "ur also can "e used to ma6e the

gingival finish line


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Torpedo "ur "eing used to create agingival finish line


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• .iamond "urs

rough surface• /mall particle si4e diamond "ur or a multi-fluted

tungsten car"ide finishing "ursmoothening ofsurface and finishing of margins

• Gingival protection- plastic instrument or gingivalretraction cord


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Proximal finish lines• +ontact point $ith ad1acent teeth should "e

maintained

• Preparation through contact point $ould reuireprovisional restoration to prevent inadvertent toothmovement "et$een tooth preparation and fitting ofthe veneers

• +ervically preparation e#tended to gingivalem"rasure to mas6 discoloured tooth su"stance inpro#imal 4one immediately a"ove the interdentalpapilla (undercut)


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• Trim pro#imal finish line $ith a chisel to avoid thesharp lip of enamel that often results from "eing

una"le to ta6e the "ur to the very edge of thepreparation

• /maller diameter "ur to prepare the pro#imal

margins of a single tooth "eing veneered


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Cervical finish lines• +hamfer $ith a"out a !? mm ma#imum depth• 5ounded internal line angle, $ill reduce stresses in

the margin of veneer• Porcelain adapts more readily to this shape during

manufacture• @inish line should lie 1ust at the crest of the free

gingival margin, unless the veneers are "eing usedto mas6 severe staining


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Coping with pre-existing restorations

• Bond to a prepared composite resin sur$ace isdi fficult, particularly if the composite restoration

has "een in place for any length of time!

• *ater sorption, e#posed un-silanated surfaces offiller particles and limited opportunities for further

polymerisation of the resin of the set materialreduced "ond strength


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Coping with pre-existing restorations

"eplace the restoration#• .one at the visit $hen the veneer is luted to the

tooth so the ne$ composite has the "est chance of

"onding to the porcelain veneer as $ell as the toothtissue• Eld restoration removed "efore the veneer is

attached

• Veneer luted in place using the reuisite "ondingsystem• +omposite resin restoration replaced in the same

manner as $hen placing a conventional +lass 000 or

0V composite filling


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• Ene of the causes for failure that .unne and 2illar identified $as that veneers $ere attached to

pre-e#isting restorations! • 0t $ould seem sensi"le to replace such restorations

at the time of veneer placement to reduce this as apossi"le cause of early failure of the veneer!

• 0f there are e#tensive restorations present it may "emore sensi"le to provide a cro$n!


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Recording an impression• /hort sections of retraction cord around the

margins of the preparations to facilitate the capture

of "oth the finishing edge of the preparation andthe ad1acent area of unprepared tooth!

• ;lectro-surgery is "est avoided "ecause of the ris6of gingival recession revealing the veneer margin!

• 9n impression of the opposing arch isindispensa"le if the incisal edges of the veneers areinvolved in guidance


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Laboratory prescription and manufacture

• /hade selection, modify colour of the tooth• /pace for the luting resin using die spacer• diagnostic $a#-up to demonstrate a modification in

anterior aesthetics• /tudy cast of the teeth prior to preparation to

preserve the original tooth form

• ;tching of venner surface $ith hydroflouric acid• /ilane-coupling agent-1ust prior to luting• Too early application or contamination can reduce

"ond strength


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Provisional restorations• Eften "est simply to leave the teeth in their prepared

state providing the patient is a$are a"out it and the

teeth are not sensitive

• .irectly placed composite resin veneers• Transparent matri# from a thermoplastic material to

allo$ multiple composite veneers to "e madesimultaneously • /pot etched onto enamel surface at the centre of

preparation leaving out the margin•

Co gingival e#cess


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• seful $hen planning to alter tooth position using veneers

• .iagnostic $a#-up can "e used to prepare a

thermoplastic matri# $hich is then used to ma6ecomposite resin veneers directly in the mouth

• &elp patient e#perience the planned changes to

their teeth at first hand and to approve the change intheir appearance "efore the definitive restorationsare made


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Trial placement• 5eturned from the la"oratory in a foam-lined "o#

• ;tched veneers should never "e put "ac6 on stonedies

• +ontact "et$een etched porcelain surface anddental stone $ill result in a"rasion of stone modeland dust may get entrapped on the veneer surfaceleading to reduced "ond strength!


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• /$ift et al # conducted a stud/ to show the e$$ecto$ contaminants and cleaning regimens on the

bond strength o$ porcelain to composite#


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Handling !orcelain veneers• +ommercially availa"le devices,• in the form of a tiny suction cup

• 5od $ith a tac6y resin at one end

• Piece of ri""on $a# on the end of an amalgamplugger


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• Teeth cleaned $ith pumice and $ater

• uality of fit and gingival e#tension chec6ed

• 9ssess the colour match

• Everall colour for the final restoration comes fromthe tooth structure, so a colour-coupling agent isneeded "et$een the tooth and the veneer

• *ater ,luting agent or trial paste


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• *ater solu"le trial paste(easy to remove)

• 5esin "ased trial pastes (organic solvent )

• 9pplication of silane coupling agent


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(he ad'antages o" using acolour)couling agent are seen here*(he 'eneer at #+1%21& loo!srelati'el, translucent %tr,)in asteused& comared -ith the oa.ue#$1%11& %no tr,)in aste used&


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Luting the veneer • 5outine use of a dentine "onding agent

advised(dentine e#posure)

• 2oisture controlru""er dam Bgingival retractioncords

• 5esidual enamel cleaned $ith pumice and $ater

• ;tched $ashed and dried,enamel Bdentin "onding

agent applied


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• Venner $ith luting resin placed onto toothsurface• ;#cess unset resin around the periphery of the veneer removed using a metal instrument or a

"rush dipped in unfilled resin• 5esin may get pulled out from the periphery of

the lute space leaving su"-margination (dentalfloss)


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• +ured using visi"le light activation unit

• ;ven though most manufacturersH suggestF?s cure time this is found to "e inadeuate

• 5esearch suggest = sec of curing time


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#ual cure resin• Epaue veneer Bthic6nessI !Amm

• Cot to "e used for thinner veneers

• .o not polymerise as effectively as a visi"le-lightactivated

• /uscepti"le to colour change $ith time as a productof the residue of the chemical initiating system


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Post placement finishing• Ecclusal interferences should "e eliminated

• /mall particle si4e diamond "urs or multi-flutedtungsten car"ide "urs

• 9"rasive dis6s or polishing pastes• Gingival tissues should "e protected "y using a flat

plastic instrument• .etailed finishing until a su"seuent appointment

,easier to identify e#cess


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/inishing the gingi'al margino" the 'eneer -ith a small articlesie diamond bur in a seedaccelerating handiece* nce again

a "lat lastic instrument rotects thgingi'al tissues

/inal olishing o" the gingi'almargin o" the 'eneer using arubber

cu and diamond olishing aste


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NON-STANA! "#N##!S

Palatal veneers%ateral porcelain slips Veneers for mandi"ular incisors

Posterior occlusal onlays


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Palatal veneers• PalatalBlingual aspect ofteeth $hich have "een $orn or fractured

• Ecclusal ad1ustment possi"le only after veneer lutedin place

• @inish lines often e#tend onto "uccal surface andresin luting agent often vis"le at the 1unction


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• Give a $avy finish line!• ;#tend finish line onto the "uccal surface of the

tooth significantly!

• 0ncrease the uantity of translucent porcelain inthe overlapping section so that more colour isdra$n from the tooth and less from the veneer!This avoids sudden change in optical properties

"et$een tooth and porcelain restoration!

• se a luting agent that is colour neutral $ith thetooth so that it "lends as much as possi"le!


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Lateral porcelain slips• sed to o"literate diastema "et$een teeth• 9void a "ul6y gingival emergence profile

• Everhangsnot cleansa"le,plaue retention• Dunction "et$een porcelain and tooth should "e

disguised finish line $ithin the intermamelon groove closest

to the addition "lend tooth and porcelain "y gradually increasing

translucent porcelain


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Veneers for mandibular incisors• Preparation usually e#tended over incisal edge of tooth, particularly if the tooth is in functional

contact!

• /ufficient thic6ness of incisal

• 0ncisal edge reduction "y "et$een !A< and ' mm

• To prevent over eruption composite resin addedonto palatal surface of opposing teeth


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Posterior occlusal onlays

• 9lso called JshimsH

• sed for aesthetic reconstruction of occlusalsurfaces of $orn or "ro6en-do$n teeth

• .e"onding and fracture seen $ith aluminous or

feldspathic porcelain

• &igh strength ceramics more suita"le for this


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CONC$%SION• Porcelain veneers are a useful ad1unct in the

management of aesthetic pro"lems in patients, "oth

young and old in a conservative manner

• +are needs to "e ta6en during tooth preparation andparticularly during the luting phase to ensure

ma#imal results


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Revie$ of literature

• Catress et al ('


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• "odr1gue2 %3 et al456&*7 conducted a study to proposea resin cement cleaning protocol for use "eforerecementing a de"onded restoration!

• They concluded that if the restoration is placed in afurnace at =


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• 9"oush K;('8)conducted a study that used "ond

strength tests to e#amine the effect of salivarycontamination on composite luting material "ond toporcelain and evaluated the effectiveness of variousprocedures used (acetone, phosphoric acid) toovercome such contamination!

• /alivary contamination reduced "ond strength >!>2Pa to '! 2pa

• 9pply silane "efore and after try-in, the porcelain $astreated $ith phosphoric acid for = seconds and a fresh

layer of silane applied!• 7ond strength increased to ?

5emoving saliva contamination from porcelain veneers "efore "onding! Aboush @!#% 9rosthet ent# &'') ec( )64?7?0'-*.


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References

• .unne / 2, 2illar 7 D! 9 longitudinal study of the clinicalperformance of porcelain veneers! Br ent % &''.( 175: 'A->'

• &ui N, *illiams 7, .avis ;, &olt 5! 9 comparative assessment ofthe strengths of porcelain veneers for incisor teeth dependent on

their design characteristics! 7r .ent D ''O'A': : '=>: ?>-?


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• +leaning and retreatment protocol for a de"onded ceramicrestoration! 5omn-5odrQgue4 D%, 9lonso-PRre4-7aruero D,7ruguera-Slvare4 9, 9gustQn-Panadero 5, @ons-@ont 9!D +lin ;#p

.ent! >'< @e"O A('):e=->! ;pu" >'< @e" '• 5emoving saliva contamination from porcelain veneers "efore "onding! Aboush @!#% 9rosthet ent# &'') ec( )64?7?0'-*.

• /$ift 7, *alls 9 *, 2c+a"e D @! Porcelain veneers: the effects ofcontaminants and cleaning regimens on the "ond strength ofporcelain to composite! Br ent % &''*( 179: >->8!

• he cience and Art o$ Porcelain %aminate Veneers ! Galip Gurel


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porcelain laminate veneers

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