Faculty of Dentistry National University of Singapore Founded 1905 Veneers

Faculty of Dentistry

National University of SingaporeFounded 1905

Veneers



Dr Charles Pincus

“ The development of dental aesthetics in the motion picture industry ”

Journal of the California Dental Association 1938



Veneers ( Pincus )• thin facings of air-

fired porcelain• temporarily held in

place with adhesive denture powder



Veneers

Direct Indirect(resin)

preformed custom lab (acrylic) fabricated

(resin, ceramic)

CAD - CAM



Direct resin bonding• advantages

can be completed in 1 visit under the control of the operator

• disadvantages susceptibility to staining poor wear and abrasion resistance time consuming prone to chipping



Indirect veneers

one-piece acrylic resin prefabricated veneer ( Faunce 1970)

laboratory formed microfill resin veneers

chemical primer applied to veneer composite resin to lute the veneer

to etched tooth



Indirect prefabricated acrylic and

lab formed resin veneers• display greater anatomical accuracy• less chairside time for dentist and patient• less polymerization shrinkage• better shading capabilities• more control of facial contours• more stain resistant



Indirect veneers

Prefabricated acrylic and laboratory formed microfill resin veneers poor resistance to abrasion tendency to delaminate at the

laminate/composite interface limited to cases not involving heavy

functional contacts



Indirect Veneers

Porcelain long history of use of porcelain 9th century Chinese 1700 France and England used

refined porcelain for dinner plates and artistic objects



Porcelain

• 18th century • Alexis Duchateau• Parisian apothecary• fabrication of denture

bases



Porcelain• Dubois de Chemant• patent to manufacture

porcelain denture teeth• 1449 – Dentist’s Supply

Company of New York process for vacuum-firing

porcelain teeth



Porcelain Veneers Technique

bonding of thin porcelain laminate to tooth surface using adhesive techniques and a luting composite to change colour, form and/or position of (anterior) tooth

Simonsen & Calamia 1983



Porcelain veneers Advantagesdimensional stabilityinsolubility in oral fluidsexcellent aestheticstissue tolerancehigh wear and abrasive resistancelongevity



Insolubility in oral fluids• more resistant to deleterious effects of

solvents eg alcohol, medications and cosmetics than resin veneers

Sheth and Jensen 1988

• much less absorption of fluids than any other veneering materials

Garber 1989



Excellent aesthetics natural and stable colour optical refractive properties similar to enamel can be intrinsically and extrinsically stained texture easily developed and maintained retains its glazed lustre over the life of the

restoration



Tissue tolerance• extremely good biocompatibility with

gingival tissues • less depository areas for plaque

accumulation Olsson et al 1992

• plaque removed more rapidly from porcelain surfaces Hahn et al 1993



Physical and mechanical properties

Acceptable tensile bond strength

resin lute – porcelain veneer 2600 – 3200 psiresin veneer – enamel 900 – 1400 psi

Calamia and Simonsen 1984



Physical and mechanical properties

Inherent porcelain strength allows reshaping porcelain veneers fragile, once cemented

develops high tensile and shear strengthCalamia

1983



Physical properties• exceptional resistance to wear and

abrasion still looks good after many years

• resistant to stain microscopic structure reveals few

voids and irregularities glazed surface



Disadvantages of porcelain veneers

• time • difficult to repair• technique - sensitive• colour• irreversible procedure



Disadvantages of porcelain veneers

• susceptibility to pitting• difficulty in resurfacing and

polishing glazed surface• fragility• cost



Indications for porcelain veneers

• discolorations eg tetracycline, devitalisation, fluorosis, aging, amalgam shine-thru’

• enamel defects eg. aging, cracks, trauma• diastemata - single or multiple• malpositioned teeth• malocclusion



Indications for porcelain veneers

• extensive anterior restorations• short teeth• agenesis of the lateral incisor• progressive wear patterns• anterior guide rehabilitations



ContraindicationsAvailable enamel not present should be enamel around the whole

periphery of the veneer –for adhesion and seal

optimal bond to enamel Troedson and Derand 1998



Contraindications

Bond of porcelain to dentine use of newest generation of DBA the bond strength of porcelain bonded to

enamel > porcelain bonded to dentine Van Meerbeek et al 1996, 1998



Contraindications

• ability to etch enamel excessive fluoridation

• oral habits bruxism, pencil chewing or ice-crushing

• occlusion class 3 or end-to-end bite



Porcelain veneers• shade selection• tooth preparation• impression• temporisation• laboratory procedures• placement • insertion• finishing• post insertion instructions and

maintenance



“ ….. patients may not always know just what they want, but they certainly know what they do not want ”



TOTAL TEAMWORK IN

AESTHETIC DENTISTRY



Shade selection

• select at the beginning of treatment• use colour corrected lighting and in

daylight• use of opaquer?• single / multiple teeth• refer to lecture on shade taking



Tooth preparation

To reduce or not to reduce

?



Tooth reduction• early concepts – minimal or no

preparation led to gingival irritation, overcontouring

and high failure rates Shaini et al 1997 Hahn et al 2000

• current beliefs support removalCalamia 1985Garber 1987

Nixon 1990

Friedman 1991



Tooth preparation – Rationale• adequate dimension for porcelain• remove convexities and provide path of

insertion• space for opaquing and resin cement• definite seating• receptive surface for etching• facilitate sulcular margin placement



Enamel reduction – contraindications

• size of pulp• patient’s psychological

state



Tooth reduction – how much?

• degree of discolouration• should remain within enamel wherever

possible and especially at the margins• relative teeth position• ceramist’s difficulty working with a thin

veneer



Tooth reduction

• 0.5 – 0.75 mm to allow for thickness of porcelain

Christensen 1991

• problem with cervical margin – usually encroaches onto the dentine

Ferrari et al 1992



Average thickness of enamel on central incisor



Tooth preparation

• labial• interproximal • sulcular• incisal/occlusal• lingual



Sulcular preparation

microleakage increases with• presence of aprismatic enamel

Peumans et al 1999, Tjan et al 1989

• prep encroaches on dentine Zaimoglu and Karaagaclioglu 1991



Incisal preparation

• window or intra-enamel• overlapped incisal edge• feathered incisal



Tooth preparation

• depth guide• hide margins in embrasure areas• place gingival margin

supragingival just into the gingival sulcus



Finish line configuration

• feather edge• rounded shoulder • chamfer -

able to accommodate adequate porcelain

proper seating and accuracy of fit



Impression

Tissue management use of retraction cord to displace

gingival tissues cord – haemostatic agent? healthy gingival tissues removal of cord? If yes, remove wet.



Impression

• polyvinylsiloxane – light and heavy/ medium viscosity

• insert from buccal oblique direction



Temporization

Unnecessary only enamel exposed minimal sensitivity and aesthetic

concerns may irritate gingiva



Temporaries – indications• reduction exposing dentine • problem of sensitivity• open contacts allowing movement of

teeth• mandibular teeth with incisal reduction• problem of aesthetics



Temporization – techniques• Direct techniques

composite veneer composite resin using vacuform matrix acrylic resin

• Indirect composite resin acrylic resin



Temporaries - attachment

• spot etchand/or unfilled bonding agent

• ensure that the periphery of the preparation is not involved or compromised by etching



Laboratory Procedures

• a good impression• bite registration• cast of opposing arch• shade selection• photograph ( optional )



Laboratory Techniques

• Refractory investment • Platinum foil



Refractory investment technique

• porcelain fired directly on a refractory die material

• preferred technique Wildgoose et al

1997



Platinum foil technique

• porcelain fired over a 0.001-inch thick platinum foil matrix

• uses individual removable dies on a master cast



Porcelain application• use of opaquer ?• built in layers

gingival third body incisal enamel

• finishing and contouring



Colour management characterization

• colour changes must be made in the porcelain itself

• communicate using photos• if colour not satisfactory during try-in ,

it is difficult to change



Etching of veneers (Lab)

etching inner surface with hydrofluoric acid and silanizing etched surface increases bond strength of a resin lute to etched enamel

Stangel et al 1987

Nicholls 1988



Hydrofluoric acid on porcelain

• dissolves glass components

• creates micropores and porosities

Peumans et al 1999Stangel et al 1987 Yen et al 1993



Etching of veneer

Using hydrofluoric acid amorphous micro-structure with

numerous porosities increase surface area for bonding micro-mechanical interlocking of the resin

compositeStangel & Nathanson 1987



SEM micrograph (magnification X 1000 )

unetched porcelain etched porcelain



Etching of veneer

• etching gel – 7.5% hydrofluoric acid• follow manufacturer’s directions

etching time concentration of etchant type of porcelain



Silane• chemical coupling agent

between resin and porcelain• improves wettability• increases adhesion• decreases microleakage

Jackson 1994



Placement

Try –in each

individual veneer

collective fit assess colour



Fit• clean teeth• veneers are extremely fragile• place a drop of glycerine or water• passive fit



Cementation

• veneer• tooth surface



Colour check

• colour dependent on tooth porcelain composite resin

• use of try-in pastes



tooth - RESIN - ceramic

• interface between veneer and tooth surface

• weak link in the system• allow for slight modification of

colour



Try in pastes

• avoid exposing resin to operating light• remove try-in paste by placing

veneers in a container of 95% alcohol, acetone or distilled water in an ultrasonic bath



Composite Resin Cements

• light curing• chemical curing• dual curing



Resin luting agents

• diacrylate resins• particle size : 0.5 - 15 microns• filler loading : 20 - 75 % inorganic

particles• particle type : silica or glass• mostly hybrids , some microfills



Composite resin cement for veneers

• a light curing composite resin is preferred longer working time better colour stability

• ensure adequate light transmittance thickness of veneer



Thickness of veneer

• thickness of 0.7 mm - resin lute does not reach its maximum hardness

Linden et al 1991

• use of dual curing resin



Insertion of veneers• tissue

management• lay out



Sequence of cementationveneer tooth(etching) prophylaxissilanation etched

primer

bonding agent cementation



Insertion of veneers• seating sequence – central incisors

first • rotate veneer into place with gentle

agitation• do not slide into place• check intimate contact with explorer



Polymerization• tack-cure for 5 - 8 secs• remove excess with brush moistened

with bonding resin• cure for at least 2 minutes each

use of 2 lights – buccal and lingual use of 13 mm diameter light tip



Finishing• after finishing of veneers, a

considerable amount of excess cement is still present

Harasani et al 1991• removes

marginal defects glaze of porcelain



Finishing and polishing

• finish equal or superior to glazed porcelain ( Haywood et al 1988) use of a series of finishing grit diamonds

(MFS) followed by a 30-fluted carbide bur diamond polishing paste

• polish under water spray (Haywood et al 1999)



Occlusal assessment

• ensure veneers do not make excessive contact with opposing arch

• use of a night-guard highly recommended



Directly milledceramic inlays and onlays

CAD-CAM systems

Computer-aided design /computer aided manufacture



CAD –CAM Systems

• Sopha Bioconcept Francois Duret

• DentiCAD Dianne Rekow• Cerec Mormannn and

Brandestini



Cerec System ( Siemens)• 1985• clinical track record• fabrication of inlays, onlays and

veneers, ¾, 7/8 and full crowns• Cerec, Cerec 2, Cerec 3



Cerec• preparation design• optical impression• computer-generated restoration

design• milling procedure• clinical placement



Celay System(Mikrona technologie AG,

Germany)• Stefan Eidenbenz 1994• tooth preparation• impression• pro-inlay fabricated• copied and reproduced in ceramic

in a milling machine



Celay system

2 aspects of the milling centreceramic block is centred in holder for manual scanning

rotary turbine with various cutting tools for cutting the replica of the plastic prototype



Maintenance

• immediate• long term



Post treatment care

First 72 -96 hours avoid hard foods, alcohol and some

medicated mouthwashes avoid extremes in temperatures maintain soft diet



Maintenance• routine cleanings

• avoid ultrasonic scaler and air abrasion systems

• use soft toothbrush with rounded bristles• floss• toothpaste – less abrasive • mouthrinses – avoid acidulated fluoride

rinses



Maintenance• avoid bad habits – pencil chewing , nail

biting• avoid biting hard foods

biting crab shells sugar cane ice chewing

• use mouth guard with any contact sports



Maintenance• avoid

staining foods and liquids eg tea, coffee

• intrinsic erosion – eating disorders

• extrinsic erosion – acidic juices and fruits



Failures• most common – fracture

modest 0 - 5% to 7 – 14%Peumans et al 2004Seymour et al 2001Friedman 1998

• marginal staining and leakageStrassler and Weiner 1998Pneumans et al 1998

composite – tooth interface due to lack of enamel caused by chromogenic bacteria and organic stains



Failures• unfavourable occlusion and articulation• significant parafunction• exposed and large dentine surfaces • partly bonded to underlying CR• Dunne & Miller

1993 Shiani et al 1997

• marginal defects – wearing out of CR lute



SUMMARY“ In vitro and in vivo studies indicate

porcelain veneers are strong and durable restorations in the medium to long term when enough intact tooth tissue to bond the porcelain veneer and articulation and occlusion are not pathological ”



Longevity• short to medium-term clinical studies • (1-5 yrs) report a low failure rate • (0-5%) due to loss of bonding and

fracture• higher failure rates ( 7 - 14%) for 3 -10

years Peumans et al 2000 (Review)

• 13 - yr study : 96.4% success Strassler 1989



Longevity

• 94.4 % at 12 yrsFradeni et al 2005

• 95 % at 5 - 6 yrs 93% at 10 -11 yrs 91% at 12- 13 yrs

Layton & Walton 2007



Co-variables for longevity studies

• design of preparation ?depthfinishing of incisal, proximal

• occlusion• presence of composite fillings• materials – type of luting resin, adhesive • method of fabrication ?• vitality



Failures

Esthetics 31%Mechanical complications 31%Periodontal support 12.5%Loss of retention 12.5%Caries 6%Tooth fracture 6%



“ ……….. All clinical studies confirm the maintenance of aesthetics of porcelain veneers in the short, medium to long term ”

Documents

Faculty of Dentistry National University of Singapore Founded 1905 Veneers