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//-->Clinical Dentistry�½Porcelain laminate veneersChoice of ceramic for use in treatments with porcelain laminate veneersAntonio Fons Font1, Mª Fernanda Solá Ruíz2, María Granell Ruíz2, Carlos Labaig Rueda1, Amparo Martínez González2(1) Assistant Professor(2) Associate Professor. Prosthodontics and Occlusion Teaching Unit. Department of Stomatology. Valencia University Medical andDental School. Valencia (Spain)Correspondence:Pof. Antonio Fons FontClínica OdontológicaC/ Gascó Oliag, 146010 ValenciaE-mail: Antonio.Fons@uv.esReceived: 10-11-2005Accepted: 12-1-2006Fons-Font, A, Solá-Ruíz MF, Granell-Ruíz M, Labaig -Rueda C, Martí-nez-González A. Choice of ceramic for use in treatments with porcelainlaminate veneers. Med Oral Patol Oral Cir Bucal 2006;11:E297-302.© Medicina Oral S. L. C.I.F. B 96689336 - ISSN 1698-6946Click here to view theIndexed in:-Index Medicus / MEDLINE / PubMed-EMBASE, Excerpta Medica-Indice Médico Español-IBECSarticle in SpanishABSTRACTPorcelain laminate veneers (PLVs) have been used for over two decades to treat esthetic and/or functional problems, par-ticularly in the anterior sector (1-3). A range of dental ceramic materials are presently available on the market for thesetreatments, though with very different characteristics in terms of the composition, optic properties and manufacturingprocesses involved. As a result, selection of the material best suited for the management of each individual patient mayprove complicated.The present study proposes a simple system for selecting the most appropriate ceramic material, based on the two varia-bles that most influence the esthetic outcome: the intrinsic characteristics of the substrate tooth, and the characteristicsof the ceramic material in terms of resistance and optic properties.Key words:Dental ceramics, porcelain classification, porcelain laminate veneers, esthetic.RESUMENEl tratamiento mediante Frentes Laminados de Porcelana (FLP) se utiliza desde hace más de dos décadas para el trata-miento de problemas estéticos y/o funcionales, particularmente en el grupo anterior de las arcadas dentarias (1,2,3). Laactual oferta en el mercado de cerámicas dentales aptas para este tipo de tratamiento, pero muy distintas en cuanto acomposición, características ópticas y sistema de elaboración, hace complicada la selección del material más adecuadoa cada paciente en particular.Proponemos un sistema sencillo de elección de la cerámica teniendo en cuenta las dos variables que más influirán en elresultado estético final: de un lado las características propias del diente (sustrato en el que nos apoyamos), y de otro lascaracterísticas propias del material cerámico en cuanto a resistencia y propiedades ópticas.Palabras clave:Cerámica dental, estética, clasificación porcelana, frentes laminados.E297Med Oral Patol Oral Cir Bucal 2006;11:E297-302.�½Porcelain laminate veneersINTRODUCTIONPorcelain laminate veneers (PLVs), also known as porce-lain facets, Horn-type facets or ceramic facets, were firstintroduced in 1938 by Charles Pincus (4), who developedporcelain facets that temporarily adhered to the vestibularsurface of the anterior teeth. The development of enameladhesion techniques in the fifties, comprising the use ofenamel etching by Buonocuore and the introduction ofbonding resins by Bowen (5), soon made it possible to applysuch PLVs to teeth on a permanent basis. Finally, in 1983,Horn (6) proposed the use of porcelain facets to cover thevestibular surface of the anterior teeth as a definitive res-toration technique.Since then the indications of this procedure have continuedto expand to the point where the use of PLVs is now com-mon practice in dental clinics. In effect, evolution of the te-chnique and materials used has led to gradual modificationsin the indications of PLVs. Thus, while in the eighties theindications were limited to the restoration of slight altera-tions in tooth shape and/or color, the present broad rangeof indications of PLVs in the anterior sector to some degreereflects the reliability of such treatment (7-11):- Correction of alterations in tooth shape or position- Changes in morphology in patients with microdontia ortooth transposition- Sealing of slight to moderate diastemas- Fractures of the incisal third- Extensive anterior dental restoration- Abrasions of parafunctional origin- Enamel alterations- Alterations in tooth color- Anterior guide rehabilitation- Repair of crown or bridge fracturesHowever, this broad range of treatment possibilities givesrise to a problem, which the present studies attempts toresolve. In effect, when dealing with this great variety ofclinical situations, not all ceramics behave as required. Asan example, a material designed to resolve slight alterationsin the color of an incisor will be of little help in the case ofanterior guide restoration in a parafunctional patient.In order to resolve the problem of which porcelain materialto use in each concrete clinical case, we propose the metho-dology used in our Prosthodontics and Occlusion TeachingUnit (Valencia University Medical and Dental School, Va-lencia – Spain), based on the characteristics of the differentceramic materials and on the needs of the specific clinicalproblem involved.A brief review is required of the classification of ceramicmaterials in order to define the best option for each concretetype of patient. Of the three possible ceramic classifications,based on sinterization temperature, composition and themanufacturing technique involved, we will focus exclusi-vely on the composition of the material, since it offers allthe information needed to resolve the problem of correctceramic choice.DENTAL CERAMICS CLASSIFICATION AC-CORDING TO COMPOSITIONDental ceramics comprise a large family of inorganic non-metal materials (12-15), and are commonly divided into twogroups: silicate ceramics and oxide ceramics.1.- SILICATE CERAMICSThe common characteristic of silicate ceramics is the pre-sence of quartz, feldspate and kaolin – the basic componentbeing silica dioxide. These are heterogeneous materials com-posed of crystals surrounded by a vitreous phase (16,17).Depending on the proportions of the different componentsand on the raw substance grain size, a broad spectrum ofceramic materials can be produced – including gres ceramics,porcelain and glass.Based on their composition, silicate porcelains can be clas-sified as feldspates or alumina porcelains.1.1.- FeldspatesThe predominant element in this case is silica oxide or quartzin a proportion of 46-66% versus 11-17% of alumina. Thefeldspate porcelains in turn are subclassified as follows:- Conventional feldspate porcelains. These offer very goodesthetic effects but the main problem is that they are fra-gile (low fracture resistance: 56.5 MPa). Examples included-SING, Vintage, Luxor, Duceram, Flexoceram, VivodentPE, IPS Classic, Empress esthetic.- High resistance feldspate porcelains. In this case we havethe following materials:(a) Feldspate porcelain reinforced with leucite crystals. Thechemical composition in this case comprises quartz (68%)and aluminum oxide (18%). As a result of the pressing pro-cess used to manufacture these materials, porosity is reducedand adequate and reproducible fit precision is achieved. Theperfect distribution of the leucite crystals within the glassmatrix, observable during the cooling phase and after pres-sing, contributes to increase resistance without significantlydiminishing translucency. The resistance to flexion is 160-300 MPa (19,20). Examples of this type of porcelain includeIPS-Empress I, Optec HSP, Mirage, Finesse, Cergogold.(b) Feldspate porcelain reinforced with lithium oxide. Thechemical composition in this case comprises quartz (57-80%), lithium oxide (11-19%) and aluminum oxide (0-5%).The incorporation of these crystalline particles increasesthe flexion resistance to 320-450 MPa, thanks to their im-portant volume (60%), homogeneous interlocking structureof densely distributed elongated crystals, and the increasein crystal size after pressing – thereby yielding a more ho-mogeneous microstructure. These porcelains are only usedto manufacture the inner coping of the restorations; thelatter are in turn covered with fluor-apatite ceramics (21).Examples of this type of porcelain include IPS Empress II,Style-Press (figure 1).1.2.- Alumina porcelainsThese porcelains contain an increased proportion of alumi-na (40-85%), while the silica oxide concentration is reducedfrom 60% to 15% (22). This group is the same as the Con-E298© Medicina Oral S.L. Email: medicina@medicinaoral.comClinical Dentistry�½Porcelain laminate veneersventional alumina porcelains. The proportion of aluminumoxide in this case does not exceed 50%. These materials areindicated for the preparation of complete crowns and forporcelain coating with aluminum oxide and metal – thoughfacets can also be manufactured. Examples of this type ofporcelain include Vitadur N, Alpha Vitadur, NBK 1000,Vita Omega 900.The internal copings are formed by a mass of compactedand practically fused crystals – thus giving rise to a nearabsence of porosities thanks to the core processing appliedin the dental laboratory, based on CAD-CAM techniques(25-27) (figure 3).An example of this ceramic is DC-Zircon (DCS), pertainingto the CDS-Precident system and composed of 95% zirco-nium oxide and 5% yttrium oxide. The zirconium moreoverreinforces the porcelain thanks to its great fracture modulus(900 MPa) and hardness (1200 Vickers units). Other availa-ble products are Lava and Everest.BCFig. 1.Specimen IPS-Empres 2 at 1000 X1: Internal coping.2: Interface.3: Overlay ceramic.AD2.- OXIDE CERAMICSThe oxide ceramics comprise both simple oxides such asaluminum oxide, zirconium dioxide and titanium dioxide, aswell as complex oxides such as spinelle, ferrite, etc. Strictlyspeaking, oxide ceramics contain only oxidant components,though the same term is commonly used in reference toceramics with blended oxide components (16). These arepolycrystalline materials with little or no vitreous phase– the latter representing the weak point of porcelain. Dueto their great opacity, they are used as internal copings inceramic restorations.2.1.- Aluminum oxide ceramicsExamples of this type of porcelain include: (a) In-CeramAlumina (85% aluminum oxide particles measuring 2-5 mmin diameter). This high alumina content affords a resistanceto flexion of 400-600 MPa; (b) In-Ceram Spinelle, wherethe substitution of alumina with mixed magnesium andaluminum oxide affords increased porcelain coping trans-lucency. This is attributable both to the crystalline origin ofthe spinelle, which confers isotropic optic properties, and tothe low refraction index of the crystals; (c) In-Ceram Zirco-nium, comprising 67% aluminum oxide and 33% zirconiumoxide and yielding a resistance to flexion of up to 600-800MPa (23); and (d) Procera All-Ceram, developed in 1993by Andersson and Odén (24). This material contains 99.9%aluminum oxides, with a fracture resistance of 680 MPa,and is in turn coated with conventional alumina ceramic(figure 2).2.2.- Zirconium oxide ceramicsZirconium oxide is a polycrystalline material with a tetrago-nal structure partially stabilized with yttrium oxideFig. 2.Specimen Procera All-ceram. Detail of the interfaceat 5000 X.A: Compact mass. B: Isolated particle. C: Prosity. D: Irre-gularity.Fig. 3.Specimen DC-Zircon at 2000 X.1: Núcleous. 2: Interface. 3: Overlay porcelain.CHOICE OF CERAMIC MATERIAL FOR MANU-FACTURING PORCELAIN LAMINATE VENEERSACCORDING TO CLINICAL INDICATIONFor correct ceramic choice, we first divide the patients interms of the PLVs once placed in the mouth, and accordingto whether they are to be subjected to functional loadingor not: (a) Type I patients: in these cases the facets are notexposed to functional loading, and are referred to as simpleesthetic facets; (b) Type II patients: in these cases the facetsare exposed to functional loading, and are referred to asfunctional esthetic facets.In this context, type I patients are candidates for conventio-nal ceramics, while type II patients require high resistanceE299Med Oral Patol Oral Cir Bucal 2006;11:E297-302.�½Porcelain laminate veneersceramics. However, this first division is incomplete, sinceit only contemplates aspects relating to resistance of theceramic material – without considering the optic characte-ristics, which are so important for ensuring good estheticresults. Type I patients are therefore in turn classified intotwo subgroups according to the background color charac-teristics of the treated teeth: (a) Type I-A patients: these aresubjects programmed to receive simple esthetic facets wherethe substrate teeth present no color alterations. The onlyobjective in this case is to apply PLVs for shape modifyingpurposes; (b) Type I-B patients: these patients are likewiseprogrammed to receive simple esthetic facets, though in thiscase the substrate teeth present color alterations. Therefore,and independently of the need for shape modifications, theselected ceramic material must be able to hide the underlyingsubstrate color.Once the patients programmed for porcelain facet treat-ment have been classified, we only need to select the dentalporcelain material best suited to the physical and opticrequirements of each case, based on the above describedmaterial classification.Type I-A patientsSince these are patients with facets that will not be subjectedto functional loading and present a clear substrate, the mate-rial used only aims to solve problems relating to tooth shape.These are consequently favorable cases, since moreover onlya small ceramic material thickness is required.In these situations we therefore recommend the use ofconventional feldspate ceramics, in view of their excellentoptic characteristics that afford optimum esthetic results.The absence of occlusal stress in these cases, and the use ofthe currently available adhesion techniques (which improveresistance to fracture of these ceramics) contribute to ensureprolonged restoration survival (figures 4a y 4b).The exception to the above is represented by cases in whichthe problem is medium or large (over 2 mm) interincisaldiastemas in the presence of a clear dental substrate. In thissetting it must be taken into account that as the porcelainextends beyond the adhesion zone, it loses the “protective”increase in elastic modulus afforded by the adhesion andcomposite resin. In these patients we therefore recommendthe use of high resistance feldspate ceramics – since theirgood esthetic qualities combine with adequate resistanceto fracture.Type I-B patientsThese patients present facets that will not bear functionalloading but which show moderate to severe alterations indental color that must be effectively masked by the res-toration. In these situations both the porcelain and cementmust present various degrees of opacity in order to hidethe color alterations, and this in turn implies problems tosecure the desired optic effects in terms of translucencyand reflectance, and consequently also esthetic outcome(figures 5a and 5b).Fig. 4a.Clinic case with multiple diastemas.Fig. 4b.Diastemas restoration with PLVs of conventionalfeldspate ceramic.Fig. 5a.Central incisor with endodontic treatment decoloration.Fig. 5b.Incisor (2.1) restoration with Empress I ceramic withopacity grade 2.E300© Medicina Oral S.L. Email: medicina@medicinaoral.comClinical Dentistry�½Porcelain laminate veneersOther characteristics to be taken into account in these casesrefers to dental preparation, which will be more aggressive(0.8-1 mm), and to the finishing line – which should beslightly subgingival and involving a curved chamfer in or-der to increase the ceramic thickness and prevent an overlynotorious tooth-restoration transition zone (figure 6).The materials indicated in such cases are ceramics offeringthe possibility of selecting the opacity of the base material,regardless of the degree of resistance.Type II patientsIn these cases the existence of functional loading in boththe mandibular static position and during excursive move-ments requires the use of a material with great resistanceto fracture. Accordingly, feldspate or alumina ceramics ofhigh resistance, and oxide ceramics are indicated.Consequently, we recommend the use of high resistanceceramics with the lost-wax casting technique (IPS EmpressII, Style Press, IPS Empress I, Optec HSP, Mirage, Finesse,Cergogold y Empress esthetic), because of its esthetic pro-perties and predictability, in long term studies, in the oralrehabilitation of the anterior guide (figures 7a and 7b).CONCLUSIONSThe use of porcelain facets to solve esthetic and/or functio-nal problems in the anterior sector has been shown to be avalid management option. Years of experience with boththe technique and the materials employed offer satisfactory,predictable and lasting results.The simple ceramic classification and definition of the typesof patients amenable to ceramic facet application proposedin the present study will help the clinician to resolve theproblem of selecting the ceramic material best suited toeach individual case.Fig. 6.Tooth preparation for a PLVs.REFERENCESFig. 7a.Clínic case with lost anterior guide because of bruxism.Fig. 7b.Restoration of the anterior guide with PLVs of highresistance feldspate porcelain.1.Torrella F, Gascón F, Castañar F. Frentes Laminados de porcelana. AVOdontoestomatol 1987;3:5-15.2. Calamia JR. Restauraciones de porcelana adherida de alta resistencia:anteriores y posteriores. Quintessence Int 1990;3:541-58.3. Karlsson S, Landahl I, Stegersjo G, Milleding P. A clinical evaluationof ceramic laminate veneers. Int J Prosthodont 1992;5:447-51.4. Pincus CR. Building mouth personality. J South Calif Dent Assoc1938;14:125-9.5. Bowen RL. Adhesive bonding of various materials to hard tooth tissues.II. Bonding to dentin promoted by a surface-active comonomer. J DentRes 1965;44:895.6. Horn HR. Porcelain laminate veneer bonded to etched enamel. DentClin North Am 1983;27:671-84.7. Haga M, Nakazawa A. Estética dental. Carillas de porcelana. Caracas:Actualidades MédicoOdontológicas LatinoAmericanas 1991.8. Cuthbirth S. Técnica indirecta de veneers de porcelana para la restaura-ción de dientes con tinción intrínseca. J Esther Dent 1993;3:2-12.9. Schmidseder J. Atlas de Odontología Estética. Barcelona: MASSON,S.A.;1999. p. 206-24.10. Dumfahrt H. Facetas de porcelana. Evaluación retrospectiva despuésde 1-10 años de servicio: Parte I-Procedimiento clínico.Rev Int PrótesisEstomatol 2000;2:103-11.11. Beltrán M, Bustos JL, González R, Solá MF. Facetas de porcelana.Revisión y actualización. Soprodent 1996;12:133-40.12.Leinfelder KF, Lemons JE. Porcelain. Clinical Restorative Materialsand Techniques. Philadelphia: Lea& Febiger; 1988.13. Mclean JW. The Science and Arto of Dental Ceramics Vol II. Chicago:Quintessece Publ Inc; 1980.14. Anglada JM, Salsench J, Nogueras J, Samsó J. Análisis de la composi-ción de algunas cerámicas dentales. Arch Odontoest 1992;8:221-4.15. Puchades O, Solá MF, Martínez A, Labaig C, Fons A, Amigó V. Estu-dio de la composición y estructura de las coronas completas de cerámica.Revista Internacional de Prótesis Estomatológica 2004;6:330-8.16. Pröbster L. El desarrollo de las restauraciones completamente cerámi-cas. Un compendio histórico (I). Quintessence (ed. Esp.) 1998;11:515-9.17. Tinschert J, Natt G., Mautsch W., Augthum M., Spiekermann HFracture resistance of lithium disilicate, alumina and zirconia basedE301
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