Modificações na forma e na textura para efeitos ópticos em dentes anteriores / Shape and texture modifications for optical effects in anterior teeth

Para se estabelecer corretamente os efeitos de forma, luz, reflexão, absorção, entre outros, nos dentes incisivos, é necessário compreendermos as características anatômicas gerais das coroas de dentes anteriores, suas linhas ópticas e como cada uma delas comanda o brilho e a reflexão. De acordo com as inclinações e ângulos formados entre as faces (vestibular, Mesial, Distal e Incisal) conseguimos trabalhar em cera ou em cerâmica as áreas ópticas com seus efeitos desejados. Este artigo aborda alguns conceitos e dicas práticas para a aquisição de áreas de sombra e luz e um resultado estético e harmonioso nos dentes anteriores.

In order to correctly establish the effects of shape, light, reflection, absorption, among others in the incisor teeth, it is necessary to understand the general anatomical characteristics of anterior tooth crowns, their optical lines and how each one rules brightness and reflection. According to the slopes and angles formed between the faces (Vestibular, Mesial, Distal and Incisal), we can work the optical areas with their desired effects with wax or ceramic. This article discusses some concepts and practical tips for acquiring shadow and light areas and an aesthetic and harmonious result in the anterior teeth.

Conceitos importantes sobre o dente canino / Important aspects of canine tooth

A Odontologia Restauradora é fundamentada numa tríade: função, biologia e estética. Muitas vezes, durante o planejamento estético, nos preocupamos com a forma, harmonia, coesão facial, cor e posição principalmente dos dentes Incisivos centrais e laterais. O canino é um dente muito importante também para todos esses efeitos e responsável pela curvatura do sorriso, dando o início do efeito paralaxe do corredor bucal. O mau posicionamento desse dente no arco pode comprometer a estética e função, afetando principalmente a guia canina. É importante lembrar que esse dente protege mutualmente o arco dentário anterior e posterior e alguns conceitos são importantes para estabelecer sua forma correta e sua posição ideal na arcada.

Restorative dentistry is based on the triad: function, aesthetics, and biology. During treatment planning, we often care about shape, facial harmony, color and position, especially when it comes to central and lateral incisors. however the canine teeth is also very important since impact all these factors. In addition canine teeth are also responsible for the curvature of the smile, initiating the buccal corridor. Poor positioning of the canines may compromise both aesthetic and function, with great impact over canine guidance. It is important to notice that this tooth protects the maxillary and mandibular arches, and some aspects must be observed in order to achieve its proper shape and position.

Técnica de injeção / Injection technique

Este trabalho mostra uma técnica de enceramento dental para posterior injeção de pastilha cerâmica. O enceramento é realizado diretamente sobre revestimento refratário, o qual é cortado em troquéis e levado ao anel para inclusão de mais revestimento. O objetivo desta técnica é realizar a injeção de estruturas muito delgadas, mantendo uma excelente adaptação uma vez que o revestimento promove esta fidelidade.

This study presents a dental wax-up technique for posterior injection of ceramic tablet. Wax-up is usually performed directly on a refractory, cutted into dies and and then coated. The aim of this technique is to perform the injection of very slim structures to achieve excellent fitting since coating enables this accuracy.

Ilusão / Ilusion

A Odontologia Restauradora e a Protése devem satisfazer as exigências estéticas do paciente e contribuir para a saúde gengival e articular (oclusão). Para tanto, muitas vezes nos deparamos com desproporções dentoalveolares, maus posicionamentos, desvios de longo-eixo, inclinações axiais desfavoráveis, presenças de diastemas, etc. Para criar a percepção ilusória de dimensões e rotações diferentes das reais, podem ser utilizados artifícios ópticos dentro dos limites de tolerância visual. Esses artifícios vão desde o trabalho com a estratificação das cores utilizadas na restauração/prótese ao planejamento adequado da área plana (ou reflexiva), ângulos incisais, área de transição, linhas de brilho, textura, pontos de con-tatos proximais, etc. Este artigo aborda alguns princípios que podemos utilizar para alterar a percepção ilusória de um dente, aproveitando-se de fenômenos ópticos na superfície do esmalte.

Restorative dentistry and dental prosthesis must meet patients' aesthetic expectations and preserve gingival and articular health. In such circumstances it is common to observe dentoalveolar disproportion, poorly positioned teeth, large, deviations of the long axis, unfa-vorable axial inclination, diastema, etc. In order to create the illusion of different dimension and rotations, optical resources can be applied respecting visual tolerance limits. These resources range from the stratification of the colors used on the restoration/prostheses to proper planning of reflexive area, incisal angles, transition areas, texture, brightness, texture and proximal contact points. The present study approaches some principles that may be used in order to improve dental appearance through optical resources over enamel surface

Bonding performance of a self-adhering flowable composite to indirect restorative materials

Introduction: Simplified restorative materials may be a logical next step for dental manufacturers. Objective: The aim of this study was to evaluate the shear bond strength of a self-adhering flowable composite to four substrates used in indirect technique. Material and methods: Twenty-four samples (5 mm wide, 15 mm length and 2 mm thick / six blocks each substrate) were prepared in the dental prosthetic laboratory. The following materials were used: ceromer (SR Adoro/AD, Ivoclar Vivadent), leucite ceramic (IPS Empress Esthetic/EE, Ivoclar Vivadent), zirconia ceramic (ZirCAD/ZI, Ivoclar Vivadent); metal ceramic alloy (Fit Cast SB/ME, Talladium do Brasil). Samples of each substrate were divided into two groups (n = 3). Two flowable composites (Control/FF - Filtek Z350 XT Flow/3M ESPE, and the self-adhering/DF - Dyad Flow/Kerr) were bonded to the four substrates. Four Tygon tubings were positioned over each sample, which were filled in with the composites FF and DF, and visible light-cured for 20 s. The tubings were removed to expose the specimens (12 per group) in format of cylinders and samples were stored in distilled water at 37±2°C for one week. After this period, each sample was attached to testing machine and the specimens were submitted to the shear bond strength test at speed of 1.0 mm/min, until failure. The results were analyzed by two-way ANOVA and Tukey test (p < 0.05). Results: The means (SD) were (in MPa): AD + FF = 34.4 ± 4.9; AD + DF = 28.2 ± 4.2; EE + FF = 29.7 ± 5.8; EE + DF = 32.3 ± 6.9; ZI + FF = 23.2 ± 5.4; ZI + DF = 8.5 ± 1.5; ME + FF = 28.9 ± 4.2; ME + DF = 31.7 ± 4.5. Conclusion: The efficacy of flowable composites is material-dependent. The self-adhering composite provided lower bond strength only to zirconia ceramic. Comparing with the control group, Dyad Flow showed lower bond strength to the ceromer and zirconia ceramic.

Bonding performance of a self-adhering flowable composite to substrates used in direct technique

Introduction: Simplified restorative materials may be a logical next step for dental manufacturers. Objective: The aim of this study was to evaluate the shear bond strength of a self-adhering flowable composite to four substrates used in direct technique. Material and methods: Eighteen samples (5 mm wide, 15 mm length and 2 mm thick) of bovine teeth - uncut enamel/UE, cut enamel/CE, median dentin/MD (6 samples each) - and blocks (also 6 samples) of the nanocomposite/NC Filtek Z350 XT (3M ESPE) were used, and samples of each substrate were divided into two groups (n = 3). Two flowable composites (Control/FF - Filtek Z350 XT Flow/3M ESPE, and the self-adhering/DF - Dyad Flow/Kerr) were bonded to the four substrates. For all groups and in each sample, four Tygon tubings were positioned over the sample, which were filled in with the composites FF and DF, and visible light-cured for 20 s. The tubings were removed to expose the cylinder-shape specimens (12 per group) and samples were stored in relative humidity at 37±2°C for one week. After this period, each sample was attached to testing machine and the specimens were submitted to the shear bond strength test at speed of 1.0 mm/min, until failure. The results were analyzed by two-way ANOVA and Tukey test (p < 0.05). Results: The means (SD) were (in MPa): UE + FF = 20.8 ± 1.0; UE + DF = 23.9 ± 3.1; CE + FF = 22.7 ± 1.8; CE + DF = 29.6 ± 5.4; MD + FF = 24.8 ± 4.5; MD + DF = 20.8 ± 3.2; NC + FF = 25.9 ± 6.2; NC + DF = 28.4 ± 5.1. Conclusion: The efficacy of flowable composites is material-dependent. The self-adhering composite provided higher bond strength on both cut enamel and nanocomposite. Comparing to the control group, Dyad Flow showed lower bond strength to median dentin, however higher bond strength to cut enamel.

Bond strength of resin cements to leucite-reinforced ceramics

Objective:The aim of this study was to evaluate the shear bond strength (SBS) of two resin cements to four leucite-reinforced ceramics. Material and methods: Forty ceramic blocks (4 mm wide, 14 mm length and 2 mm thick) were used and the samples abraded with aluminum oxide (90 µm). The samples were divided into eight groups (n = 5). Two resin cements (conventional RelyX ARC and self-adhesive RelyX U100 - 3M ESPE) were bonded to Creapress (CRE-Creation/Klema), Finesse All-Ceramic (FIN-Dentsply/ Ceramco), IPS Empress Esthetic (IEE-Ivoclar Vivadent) and Vita PM9 (PM9-Vita). For all groups and in each ceramic block, after application of 10% hydrofluoric acid and silanation, three Tygon tubings were positioned over the ceramics, which were filled in with the resin cements (light-cure for 40 s). The tubings were removed to expose the specimens in format of cylinders (area: 0.38 mm2) and samples were stored in relative humidity at 24±2 °C for one week. After this period, each sample was attached to testing machine and the specimens were submitted to shear bond test (applied at the base of the specimen/cement cylinder with a thin wire/0.2 mm) at speed of 0.5 mm/ min, until failure. The results were analyzed by two-wayANOVA (resin cements and ceramic systems) and Tukey test (p<0.05). Results: The means (SD) were (in MPa): ARC + CRE = 32.1±4.3; ARC + FIN = 28.3±3.7; ARC + IEE = 25.9±4.4; ARC + PM9 = 22.2±2.1; U100 + CRE = 38.0±5.2; U100 + FIN = 36.9±2.8; U100 + IEE = 38.4±2.9; U100 + PM9 = 34.3 ±7.3. U100 showed higher SBS to ceramics than ARC. U100 had higher SBS when applied on IEE ceramic than on PM9. For ARC, SBS obtained with CRE was higher than with IEE and PM9. Conclusion: RelyX U100 can provide higher SBS to leucite-reinforced ceramics than conventional resin cement. The resin cements applied on the PM9 ceramic surface resulted in lower SBS.