Case report: Vertical preparation protocol for veneers.

The biologically oriented preparation technique (BOPT) consists of a vertical preparation of the tooth that involves a reduction to zero of the emergence anatomy, the creation of a new finish area, and immediate temporization, so that the gingiva is supported by a suitable prosthetic restoration. To this effect, it is not the restoration that adapts to the gingiva, but the gingiva that adapts to the restoration. This technique not only allows the gingiva around the tooth to stabilise, but over time it will also facilitate the achievement of a predictable coronal migration of the gingival margin. The present paper describes the protocol from dental preparation to the cementation of the BOPT veneers, highlighting the differences with the established protocol for full coverage crowns and the protocol we have followed for many years for veneers with finish lines. Key words:Veneers, vertical preparation, BOPT.

Brain morphology correlates of learning and cognitive flexibility in a fish species (Poecilia reticulata).

Determining how variation in brain morphology affects cognitive abilities is important to understand inter-individual variation in cognition and, ultimately, cognitive evolution. Yet, despite many decades of research in this area, there is surprisingly little experimental data available from assays that quantify cognitive abilities and brain morphology in the same individuals. Here, we tested female guppies (Poecilia reticulata) in two tasks, colour discrimination and reversal learning, to evaluate their learning abilities and cognitive flexibility. We then estimated the size of five brain regions (telencephalon, optic tectum, hypothalamus, cerebellum and dorsal medulla), in addition to relative brain size. We found that optic tectum relative size, in relation to the rest of the brain, correlated positively with discrimination learning performance, while relative telencephalon size correlated positively with reversal learning performance. The other brain measures were not associated with performance in either task. By evaluating how fast learning occurs and how fast an animal adjusts its learning rules to changing conditions, we find support for that different brain regions have distinct functional correlations at the individual level. Importantly, telencephalon size emerges as an important neural correlate of higher executive functions such as cognitive flexibility. This is rare evidence supporting the theory that more neural tissue in key brain regions confers cognitive benefits.

Influence of bruxism on survival of porcelain laminate veneers

OBJECTIVE: This study aims to determine whether bruxism and the use of occlusal splints affect the survival of porcelain laminate veneers in patients treated with this technique. MATERIAL AND METHODS: Restorations were made in 70 patients, including 30 patients with some type of parafunctional habit. A total of 323 veneers were placed, 170 in patients with bruxism activity, and the remaining 153 in patients without it. A clinical examination determined the presence or absence of ceramic failure (cracks, fractures and debonding) of the restorations; these incidents were analyzed for association with bruxism and the use of splints. RESULTS: Analysis of the ceramic failures showed that of the 13 fractures and 29 debonding that were present in our study, 8 fractures and 22 debonding were related to the presence of bruxism. CONCLUSIONS: Porcelain laminate veneers are a predictable treatment option that provides excellent results, recognizing a higher risk of failure in patients with bruxism activity. The use of occlusal splints reduces the risk of fractures

Influence of bruxism on survival of porcelain laminate veneers.

OBJECTIVE: This study aims to determine whether bruxism and the use of occlusal splints affect the survival of porcelain laminate veneers in patients treated with this technique. MATERIAL AND METHODS: Restorations were made in 70 patients, including 30 patients with some type of parafunctional habit. A total of 323 veneers were placed, 170 in patients with bruxism activity, and the remaining 153 in patients without it. A clinical examination determined the presence or absence of ceramic failure (cracks, fractures and debonding) of the restorations; these incidents were analyzed for association with bruxism and the use of splints. RESULTS: Analysis of the ceramic failures showed that of the 13 fractures and 29 debonding that were present in our study, 8 fractures and 22 debonding were related to the presence of bruxism. CONCLUSIONS: Porcelain laminate veneers are a predictable treatment option that provides excellent results, recognizing a higher risk of failure in patients with bruxism activity. The use of occlusal splints reduces the risk of fractures.

Survival rates of a lithium disilicate-based core ceramic for three-unit esthetic fixed partial dentures: a 10-year prospective study.

PURPOSE: The aim of this prospective study was to evaluate the clinical efficacy and long-term survival rate of three-unit fixed partial dentures (FPDs) made from lithium disilicate-based core ceramic. MATERIALS AND METHODS: Twenty-one three-unit FPDs were placed in 19 patients to replace single lost teeth in the esthetic area, following a study protocol that took clinical, esthetic, and radiologic aspects into consideration. Each case was reviewed at 1 week following placement, at 6 months, and then annually for 10 years. Statistical analysis was performed using Kaplan-Meier survival analysis. RESULTS: Out of the 19 patients, 14.3% presented reversible postoperative sensitivity. Recession was observed in 24% of dental posts, and 7.1% presented marginal discoloration. Treatment did not increase either Bleeding or Plaque Index scores at prepared teeth; secondary caries did not appear either. The restorations' survival rate at the 10-year follow-up was 71.4%; six FPDs had fractured and one debonded. CONCLUSIONS: Fracture failure rate was 28.6% after 10 years; a high percentage corresponded to connector fractures and occurred during the first 5 years. Lithium disilicate glass-ceramic FPDs present a higher risk of fracture than standard therapies (metal-ceramic) or other more recently developed ceramic materials. The prognosis for survival improves for Class I occlusion and nonparafunctional patients.

Bond strength of selected composite resin-cements to zirconium-oxide ceramic

Objectives: The aim of this study was to evaluate bond strengths of zirconium-oxide (zirconia) ceramic and a selection of different composite resin cements. Study Design: 130 Lava TM cylinders were fabricated. The cylinders were sandblasted with 80 µm aluminium oxide or silica coated with CoJet Sand. Silane, and bonding agent and/or Clearfil Ceramic Primer were applied. One hundred thirty composite cement cylinders, comprising two dual-polymerizing (Variolink II and Panavia F) and two autopolymerizing (Rely X and Multilink) resins were bonded to the ceramic samples. A shear test was conducted, followed by an optical microscopy study to identify the location and type of failure, an electron microscopy study (SEM and TEM) and statistical analysis using the Kruskal-Wallis test or more than two independent samples and Mann-Whitney for two independent samples. Given the large number of combinations, Bonferroni correction was applied (alfa=0.001). Results: Dual-polymerizing cements provided better adhesion values (11.7 MPa) than the autopolymerizing (7.47 MPa) (p-value M-W<0.001). The worst techniques were Lava TM + sandblasting + Silane + Rely X; Lava TM + sandblasting + Silane + Multilink and Lava TM + CoJet + silane + Multilink. Adhesive failure (separation of cement and ceramic) was produced at a lesser force than cohesive failure (fracture of cement) (p-value M-W<0.001). Electron microscopy confirmed that the surface treatments modified the zirconium-oxide ceramic, creating a more rough and retentive surface, thus providing an improved micromechanical interlocking between the cement and the ceramic. Conclusions: Best results were provided by dual-polymerizing cements associated with sandblasting or silica coating and a bonding agent containing MDP (AU)

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Fractographic study of the behavior of different ceramic veneers on full coverage crowns in relation to supporting core materials.

OBJECTIVES: To observe porcelain veneer behavior of zirconia and metal-ceramic full coverage crowns when subjected to compression testing, comparing zirconia cores to metal cores. STUDY DESIGN: The porcelain fracture surfaces of 120 full coverage crowns (60 with a metal core and 60 with a zirconia core) subjected to static load (compression) testing were analyzed. Image analysis was performed using macroscopic processing with 8x and 12x enlargement. Five samples from each group were prepared and underwent scanning electron microscope (SEM) analysis in order to make a fractographic study of fracture propagation in the contact area and composition analysis in the most significant areas of the specimen. RESULTS: Statistically significant differences in fracture type (cohesive or adhesive) were found between the metal-ceramic and zirconia groups: the incidence of adhesive fracture was seen to be greater in metal-ceramic groups (92%) and cohesive fracture was more frequent in zirconium oxide groups (72%). The fracture propagation pattern was on the periphery of the contact area in the full coverage crown restorations selected for fractographic study. CONCLUSIONS: The greater frequency of cohesive fracture in restorations with zirconia cores indicates that their behavior is inadequate compared to metal-ceramic restorations and that further research is needed to improve their clinical performance. Key words:Zirconia, zirconium oxide, fractography, composition, porcelain veneers, fracture, cohesive, adhesive.

Bond strength of selected composite resin-cements to zirconium-oxide ceramic.

OBJECTIVES: The aim of this study was to evaluate bond strengths of zirconium-oxide (zirconia) ceramic and a selection of different composite resin cements. STUDY DESIGN: 130 Lava TM cylinders were fabricated. The cylinders were sandblasted with 80 µm aluminium oxide or silica coated with CoJet Sand. Silane, and bonding agent and/or Clearfil Ceramic Primer were applied. One hundred thirty composite cement cylinders, comprising two dual-polymerizing (Variolink II and Panavia F) and two autopolymerizing (Rely X and Multilink) resins were bonded to the ceramic samples. A shear test was conducted, followed by an optical microscopy study to identify the location and type of failure, an electron microscopy study (SEM and TEM) and statistical analysis using the Kruskal-Wallis test for more than two independent samples and Mann-Whitney for two independent samples. Given the large number of combinations, Bonferroni correction was applied (α=0.001). RESULTS: Dual-polymerizing cements provided better adhesion values (11.7 MPa) than the autopolymerizing (7.47 MPa) (p-value M-W<0.001). The worst techniques were Lava TM + sandblasting + Silane + Rely X; Lava TM + sandblasting + Silane + Multilink and Lava TM + CoJet + silane + Multilink. Adhesive failure (separation of cement and ceramic) was produced at a lesser force than cohesive failure (fracture of cement) (p-value M-W<0.001). Electron microscopy confirmed that the surface treatments modified the zirconium-oxide ceramic, creating a more rough and retentive surface, thus providing an improved micromechanical interlocking between the cement and the ceramic. CONCLUSIONS: Best results were provided by dual-polymerizing cements associated with sandblasting or silica coating and a bonding agent containing MDP.

Zirconia versus metal: a preliminary comparative analysis of ceramic veneer behavior.

PURPOSE: Clinical studies have revealed a high rate of fracture for porcelain-veneered zirconia-based restorations that varies between 6% and 15% over a 3- to 5-year period. These are high values compared to the 4% fracture rate shown by conventional metal-ceramic restorations over 10 years. To date, little in vitro research has been carried out on the fracture resistance of the new generation of ceramic crowns. The aims of this study were to develop preliminary research on the mechanical failure behavior of three types of porcelain-veneered crowns with zirconia cores when subjected to static compressive loading and to analyze fracture characteristics using scanning electron microscopy (SEM). MATERIALS AND METHODS: Eighty individual full-coverage crowns were studied: 60 crowns with a zirconia core and 20 with a metal core (control). RESULTS: Values obtained in compressive testing were as follows: ZirPress: 1,818.01 N, ZirCAD: 1,773.92 N, Lava: 2,210.95 N, and metal-ceramic (control): 2,310.49 N. SEM analysis revealed that 71.66% of zirconia-based restoration mechanical failures were cohesive, while 100% of mechanical failures for metal-ceramic restorations were adhesive. CONCLUSIONS: The mechanical behavior of the porcelain veneering on a zirconia core is more fragile than that on metal-ceramic crowns, and when load forces exerted on these restorations lead to mechanical failure, this will occur in the interior of the porcelain veneering.

Full maxillary rehabilitation with an all-ceramic system

With the appearance of all-ceramic systems, providing a choice of framework porcelains and allowing the samematerial to be used for the veneer, it is now possible to select the ideal structure in terms of both function andesthetics. Silicate ceramics allow porcelain laminate veneers and crowns to be used in the anterior region, providingexcellent esthetics; while for the posterior area, where function takes precedence, oxide ceramics, specificallyzirconium oxide, are preferred. The IPS e.max ceramic system, heir apparent to the IPS Empress 2 system,combines the advantages of zirconium oxide ceramics (IPS e.max Zircad) with the excellent esthetic qualities ofsilicate ceramics (IPS e.max Press).This paper presents a clinical case requiring complete maxillary rehabilitation for esthetic purposes. An overviewof some of the porcelains used in this system, analyzed from both the clinical and laboratory perspective is provided.The esthetic advantages of a single ceramic veneer, the need to select appropriate ceramics for anterior andposterior regions, and cementation and surface treatments are discussed (AU)

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A clinical longitudinal study 323 porcelain laminate veneers. Period of study from 3 to 11 years

Objective: The objective of this study was to evaluate the clinical results of 323 porcelain laminate veneers overa period of 3 to 11 years.Material and Methods: This study included 70 patients, aged between 18 and 74 years. Of the 323 total veneers,124 were of a simple design and 199 were of a functional design. The condition of the soft tissues and hygiene, inaddition to the condition of the abutment teeth, the restorations and patient satisfaction were all clinically examined.In carrying out the statistical analysis, a descriptive approach was taken in analyzing the data. The KaplanMeier method was used for statistically analyzing the survival rates of the porcelain laminate veneers.Results: Analysis of the soft tissue revealed marginal recession in 7.7% of the cases, and in 21.6% of the cases,bleeding was detected on probing. Analysis of the condition of the abutment teeth revealed secondary caries andhypersensitivity in 3.1% of the cases, and changes in pulp vitality were observed in 2.8% of the cases. In studyingthe condition of the restorations, marginal integrity was observed to be excellent in 98% of the cases, slight marginalpigmentation was present in 39.3% of the cases, fractures were present in 4% of the cases and decementationin 9% of the cases. The degree of patient satisfaction was considered to be excellent in 97.1% of the cases.Conclusions: Porcelain laminate veneers are a predicable treatment option that offer excellent results (AU)

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In vitro experimental study of bonding between aluminium oxide ceramicsand resin cements

To evaluate bond strengths of different resin cements to two aluminum oxide-based ceramics. Methods: Onehundred ten ceramic cylinders were produced and given four different surface treatments. Resin cement cylinderswere then bonded to the ceramic cylinders using different resin cements and the bond strength was determinedby shear testing to the breaking point. We were thus able to obtain results for the different combinations of porcelain,surface treatments and cements. All data was analyzed using the Kruskal-Wallis test for more than twoindependent samples and the Bonferroni correction applied (a=0.01). An optical microscopy study was carriedout to analyze the type of failure, and an electronic microscopy examination was carried out in order to evaluatethe changes produced in the ceramic by the different surface treatments. Results: The best values correspondedto the control group, composed of silicate ceramics combined with Variolink II resin cement. In-Ceram Aluminashowed no significant differences with respect to the type of cement applied. Procera AllCeram obtained the bestvalues when silica coated using the CoJet System and applying Variolink II, or when sandblasted and applyingClearfil SE Bond + Porcelain Bond Activator and Panavia F cement. Significance: Surface treatment modifies theceramic surface and influences the bond strength, as does the type of cement used. Silica coating is recommendedto improve adhesion to Procera AllCeram, applying Variolink II, or sandblasting plus resin cement containingMDP (Panavia F) (AU)

No disponible

A clinical longitudinal study 323 porcelain laminate veneers. Period of study from 3 to 11 years.

OBJECTIVE: The objective of this study was to evaluate the clinical results of 323 porcelain laminate veneers over a period of 3 to 11 years. MATERIAL AND METHOD: This study included 70 patients, aged between 18 and 74 years. Of the 323 total veneers, 124 were of a simple design and 199 were of a functional design. The condition of the soft tissues and hygiene, in addition to the condition of the abutment teeth, the restorations and patient satisfaction were all clinically examined. In carrying out the statistical analysis, a descriptive approach was taken in analyzing the data. The Kaplan Meier method was used for statistically analyzing the survival rates of the porcelain laminate veneers. RESULTS: Analysis of the soft tissue revealed marginal recession in 7.7% of the cases, and in 21.6% of the cases, bleeding was detected on probing. Analysis of the condition of the abutment teeth revealed secondary caries and hypersensitivity in 3.1% of the cases, and changes in pulp vitality were observed in 2.8% of the cases. In studying the condition of the restorations, marginal integrity was observed to be excellent in 98% of the cases, slight marginal pigmentation was present in 39.3% of the cases, fractures were present in 4% of the cases and decementation in 9% of the cases. The degree of patient satisfaction was considered to be excellent in 97.1% of the cases. CONCLUSIONS: Porcelain laminate veneers are a predicable treatment option that offer excellent results.

Full maxillary rehabilitation with an all-ceramic system.

With the appearance of all-ceramic systems, providing a choice of framework porcelains and allowing the same material to be used for the veneer, it is now possible to select the ideal structure in terms of both function and aesthetics. Silicate ceramics allow porcelain laminate veneers and crowns to be used in the anterior region, providing excellent aesthetics; while for the posterior area, where function takes precedence, oxide ceramics, specifically zirconium oxide, are preferred. The IPS e.max ceramic system, heir-apparent to the IPS Empress 2 system, combines the advantages of zirconium oxide ceramics (IPS e.max Zircad) with the excellent aesthetic qualities of silicate ceramics (IPS e.max Press). This paper presents a clinical case requiring complete maxillary rehabilitation for aesthetic purposes. An overview of some of the porcelains used in this system, analyzed from both the clinical and laboratory perspective is provided. The aesthetic advantages of a single ceramic veneer, the need to select appropriate ceramics for anterior and posterior regions, and cementation and surface treatments are discussed.

In vitro experimental study of bonding between aluminium oxide ceramics and resin cements.

UNLABELLED: To evaluate bond strengths of different resin cements to two aluminum oxide-based ceramics. METHODS: One hundred ten ceramic cylinders were produced and given four different surface treatments. Resin cement cylinders were then bonded to the ceramic cylinders using different resin cements and the bond strength was determined by shear testing to the breaking point. We were thus able to obtain results for the different combinations of porcelain, surface treatments and cements. All data was analyzed using the Kruskal-Wallis test for more than two independent samples and the Bonferroni correction applied (a=0.01). An optical microscopy study was carried out to analyze the type of failure, and an electronic microscopy examination was carried out in order to evaluate the changes produced in the ceramic by the different surface treatments. RESULTS: The best values corresponded to the control group, composed of silicate ceramics combined with Variolink II resin cement. In-Ceram Alumina showed no significant differences with respect to the type of cement applied. Procera AllCeram obtained the best values when silica coated using the CoJet System and applying Variolink II, or when sandblasted and applying Clearfil SE Bond + Porcelain Bond Activator and Panavia F cement. SIGNIFICANCE: Surface treatment modifies the ceramic surface and influences the bond strength, as does the type of cement used. Silica coating is recommended to improve adhesion to Procera AllCeram, applying Variolink II, or sandblasting plus resin cement containing MDP (Panavia F).

Choice of ceramic for use in treatments with porcelain laminate veneers.

Porcelain laminate veneers (PLVs) have been used for over two decades to treat esthetic and/or functional problems, particularly in the anterior sector. A range of dental ceramic materials are presently available on the market for these treatments, though with very different characteristics in terms of the composition, optic properties and manufacturing processes involved. As a result, selection of the material best suited for the management of each individual patient may prove complicated. The present study proposes a simple system for selecting the most appropriate ceramic material, based on the two variables that most influence the esthetic outcome: the intrinsic characteristics of the substrate tooth, and the characteristics of the ceramic material in terms of resistance and optic properties.

Selección de la ceramica a utilizar en tratamientos mediante frentes laminados de porcelana / Choice of ceramic for use in treatments with porcelain laminate veneers

El tratamiento mediante Frentes Laminados de Porcelana (FLP) se utiliza desde hace más de dos décadas para el tratamiento de problemas estéticos y/o funcionales, particularmente en el grupo anterior de las arcadas dentarias (1,2,3). La actual oferta en el mercado de cerámicas dentales aptas para este tipo de tratamiento, pero muy distintas en cuanto a composición, características ópticas y sistema de elaboración, hace complicada la selección del material más adecuado a cada paciente en particular. Proponemos un sistema sencillo de elección de la cerámica teniendo en cuenta las dos variables que más influirán en el resultado estético final: de un lado las características propias del diente (sustrato en el que nos apoyamos), y de otro las características propias del material cerámico en cuanto a resistencia y propiedades ópticas

Porcelain laminate veneers (PLVs) have been used for over two decades to treat esthetic and/or functional problems, particularly in the anterior sector (1-3). A range of dental ceramic materials are presently available on the market for these treatments, though with very different characteristics in terms of the composition, optic properties and manufacturing processes involved. As a result, selection of the material best suited for the management of each individual patient may prove complicated. The present study proposes a simple system for selecting the most appropriate ceramic material, based on the two variables that most influence the esthetic outcome: the intrinsic characteristics of the substrate tooth, and the characteristics of the ceramic material in terms of resistance and optic properties

Frentes laminados de porcelana: discusión de los procedimientos clínicos y de laboratorio / Porcelain Laminate Veneers: Discussion of clinical and technical procedures

Introducción: En nuestra experiencia de 14 años realizando este tipo de restauraciones en la Unidad Docente de Prostodoncia y Oclusión de la Universidad de Valencia, a lo largo de los cuales hemos tratado 150 pacientes para un total de 450 carillas. Ello nos ha conducido a una serie de modificaciones en los parámetros propuestos en la literatura de los últimos años, para poder adaptarnos a las necesidades específicas de los pacientes en función de la indicación inicial y el diagnóstico preciso de cada caso. Material y método: analizamos y discutimos los procedimientos clínicos empleados desde la reducción de tallado según la indicación, hasta la técnica de cementado y cemento utilizado, pasando por la toma de impresiones, técnica de confección de laboratorio, elección del tipo de cerámica y pruebas clínicas de ajuste y comprobación del color. Resultados en nuestro estudio longitudinal realizado sobre una muestra parcial de 160 restauraciones, observamos unos resultados favorables en el 81 por ciento de los casos. El 9 por ciento de fracasos se distribuyeron de la siguiente manera: 4 fracturas, 5 descementados inmediatos y 5 descementados tardíos. Conclusión los frentes laminados de porcelana nos ofrecen una alternativa prostodóncica con resultado estético y resistencia mecánica óptimos (AU)