Caracterizações física e química de cimentos experimentais autoadesivos à base de cálcio / Physical and chemical characterizations of calcium-based self-adhesive experimental cements

Objetivo: Avaliar a Resistência de União (RU), Grau de Conversão (GC), Liberação de Cálcio (LC), Resistência Flexural (RF), Módulo de Elasticidade (ME) e Viscosidade (VS) de cimentos experimentais à base de cálcio autocondicionantes e autoadesivos. Três cimentos experimentais: A (CONTROLE) ­ sem fonte de cálcio, B (HIDROCAL) ­ com hidróxido de cálcio, C (CLORECAL) ­ com cloreto de cálcio foram sintetizados e avaliados juntamente a um cimento comercial D (ULTRAPLUS) (Ultra-Blend Plus®). Metodologia: Para a RU, foi utilizado o teste de cisalhamento, cujas amostras (1,3mm de diâmetro com 2mm de altura) foram aderidas à dentina bovina (n=10) e tensionadas em máquina de ensaios (1 mm/min) até́ ocorrer o deslocamento. Para o GC (n=3), foi utilizada a Espectroscopia Infravermelha com transformada de Fourier (FTIR). Na determinação da LC (n=3) foram utilizadas amostras circulares (1,0 mm x 0,4 mm) e a leitura foi realizada através de um espectrofotômetro de absorção atômica nos tempos de 3h, 24h e 72h. Para RF/ME (n=10), amostras em formato de barra (7mm x 2mm x 1mm) foram confeccionadas e avaliadas por meio de uma Máquina de Ensaios Universal no teste de flexão de três pontos. Para a VS (n=30), a variação da taxa de deformação foi determinada por um reômetro rotacional de cilindros concêntricos. Os dados foram analisados por ANOVA 1 e 2 fatores seguido pelo pós teste de tukey (p<0,05). Resultados: Para RU todos os materiais experimentais apresentaram valores estatisticamente maiores que o comercial (p<0,01). Para o GC os cimentos CONTROLE e HIDROCAL apresentaram valores estatisticamente maiores que os demais (p<0,01). Frente à LC o CLORECAL e ULTRAPLUS apresentaram valores estatisticamente superiores após 72h (p<0,01). O ULTRAPLUS apresentou estatisticamente a maior RF e o menor ME (p<0,05). Os cimentos HIDROCAL e CLORECAL apresentaram valores de VS estatisticamente superiores aos demais (p<0,01). Conclusão: De maneira geral, o cimento experimental à base de cloreto de cálcio mostrou-se mais promissor (AU).

Objective: To evaluate the Bond Strength (BS), Degree of Conversion (DC), Calcium Release (CR), Flexural Strength (FS), Elastic Modulus (EM) and Viscosity (VS) of experimentally calcium based cements self-etching and self-adhesive. Three experimental cements: A (CONTROL), B (HYDROCAL), C (CLORECAL) were synthesized and evaluated with a commercial cement D (ULTRAPLUS) (Ultra-Blend Plus®- South Jordan, Utah, USA). Methodology: For the BS, the shear test was used, whose samples 1.3mm in diameter and 2mm in height) were adhered to the bovine dentin (n=10) and tensioned in a testing machine (1mm/min) until occurring the displacement. For the DC (n=3), Infrared Spectroscopy with Fourier transform (FTIR) was used. In determining the CR (n = 3) circular samples (1.0mmx0.4 mm) were used and the reading was performed through an atomic absorption spectrophotometer at 3h, 24h and 72h. For FS/ ME (n= 0), bar-shaped samples (7mmx 2mmx1mm) were made and evaluated using a Universal Testing Machine in the three-point flexion test. For VS (n = 30), the variation in the strain rate was determined by a rotational concentric cylinder rheometer. Results: For BS, all experimental materials showed statistically higher values than the commercial material (p <0.01). For the DC, the CONTROL and HIDROCAL cements showed statistically higher values than the others (p <0.01). In relation to CR, CLORECAL and ULTRAPLUS showed statistically higher values after 72 hours (p <0.01). ULTRAPLUS showed statistically the highest FS and the lowest EM (p <0.05). The HIDROCAL and CLORECAL cements showed VS values statistically higher than the others (p <0.01) Conclusion: In general, the experimental cement based on calcium chloride proved to be more promising (AU).

Interfacial properties and bottom/top hardness ratio produced by bulk fill composites in dentin cavities

Abstract The aim of this study was to evaluate the bond strength, bottom/top hardness ratio, marginal adaptation, and interfacial nanoleakage of regular viscosity bulk fill composites (RVBFC) and regular viscosity traditional composites (RVTC). Two RVBFC (Filtek Bulk Fill and Aura Bulk Fill) and two RVTC (Filtek Z250XT and Aura) were assessed. Forty conical cavities (4.8×2.8×4.0) were prepared in bovine dentin and restored with composites (n=10). After 24h in water, marginal adaptation was evaluated by staining with a caries detector. The top and bottom surfaces of the conical restorations were stained for five seconds and the gap percentage in the composite/dentin interface was determined using digital images on a measurement program (ImageTool). The Vickers microhardness was measured and the bottom/top microhardness ratio (B/T) was determined. Push-out bond strength test was performed in a universal testing machine (0.5mm/min) and failure modes were evaluated in a stereomicroscope (20×). Other specimens (n=3) were produced for interfacial nanoleakage evaluation. Data were analyzed using one and two-way ANOVA and Tukey's test (α=0.05). The gap percentage was higher in the bottom compared to the top. The B/T ratio of the Aura Bulk Fill was statistically lower than other composites. Push-out bond strength were similar among composites. The RVBFC presented lower nanoleakage than the RVTC in the bottom of the conical restoration and there was no difference among the materials in the top surfaces. In conclusion, Filtek Bulk Fill performed better than Aura Bulk Fill regarding the analyzed properties.

Resumo O objetivo deste estudo foi avaliar a resistência de união, razão base/topo de microdureza, adaptação marginal e nanoinfiltração interfacial de resinas compostas bulk fill (BF) e tradicional (RT) de viscosidade regular.: Duas BF (Filtek Bulk Fill e Aura Bulk Fill) e duas RT (Filtek Z250XT e Aura) foram testados. Quarenta cavidades cônicas (4,8×2,8×4,0) foram preparadas em dentina bovina e restauradas com os compósitos (n=10). Depois de 24 h em água, a adaptação marginal foi avaliada por meio do corante com detector de cárie. As faces de topo e base das restaurações cônicas foram coradas por cinco segundos e a porcentagem de fendas na interface compósito/dentina foi determinada utilizando-se imagens analisadas num programa (ImageTool). A microdureza Vickers foi mensurada e a razção base/topo de microdureza (B/T) foi determinada. A resistência de união por push-out foi executada numa máquina de ensaios universal (0,5mm/min) e o padrão de fratura avaliado num estereomicroscópio (20x). Espécimes adicionais (n=3) foram confeccionados para avaliação da nanoinfiltração interfacial. Os dados foram analisados por meio de ANOVA a dois fatores e teste de Tukey (a=0,05). A porcentagem de fendas foi maior na base que no topo. A B/T da Aura Bulk Fill foi estatisticamente menor que os demais compósitos. A resistência de união por push-out foi similar entre os compósitos. As BF apresentaram menos nanoinfiltração que as RT na base das restaurações cônicas e não houve diferenças entre os materiais no topo. Conclui-se que a Filtek Bulk Fill comportou-se melhor que a Aura Bulk Fill considerando-se as propriedades analisadas.

Polymerization capability of simplified dental adhesives with camphorquinone, phenyl-propanedione and bis-alkyl phosphine photoinitiators

Aim: this study aimed to evaluate the degree of conversion (DC) exhibited by novel formulations of dental adhesive systems including camphorquinone (CQ), phenyl-propanedione (PPD), and bis-alkyl phosphine oxide (BAPO) when cured by mono- or polywave light emitting diodes (LEDs). Methods: an adhesive model was formulated by mixing hydroxyethyl methacrylate (HEMA, 40 wt%) and bisphenol A glycidyl dimethacrylate (BisGMA, 60 wt%) in ethanol (30 wt%). Five materials were then formulated by adding the following photoinitiators: CQ (1 mol%), CQ/PPD (0.5/0.5 mol%), CQ/BAPO (0.5/0.5 mol%), PPD (1 mol%), and BAPO (1 mol%). The DC for each material was measured with Fourier transform infrared spectroscopy. Analysis of variance and Tukey's post-hoc test were used to analyze the data (p < 0.05). Results: Except for CQ, the photoinitiators provided a significantly higher DC in the adhesive systems following photoactivation with a polywave LED. Conclusion: The use of alternative photoinitiators and a polywave LED improved the DC of the adhesive systems examined

Shear Bond Strength and Adhesive Remnant of Three Protocols used for Bonding Orthodontic Brackets

Objective: To test the shear bond strength and the amount of adhesive remnant on the enamel after debonding of a conventional orthodontic composite system, a flowable composite resin, and a self-adhesive resin cement. Material and Methods: Thirty extracted bovine incisors were allocated in three groups, according to the type of adhesive: Group XT (Transbond XT), Group FL (Flow Z350), and Group RX (RelyX U100). All groups had etching with phosphoric acid. Groups XT and FL received primer before adhesive. Stainless steel metal brackets were bonded using the respective adhesive. Teeth were submitted to shear bond strength (SBS) test, followed by measurement of adhesive remnant. Intergroup comparison of SBS values were performed by one-way Anova and Tukey post-hoc test. Kruskal-Wallis test and the Mann-Whitney U-test were used to compare adhesive remnant. Results: Transbond XT presented higher bond strength than RelyX U100 and Flow Z350; all adhesives exhibited bond failure within the adhesive. All groups showed bond failure occurring within the adhesive. Transbond XT and RelyX U100 left significantly more adhesive remnant on the tooth surface than Flow Z350. Conclusion: All three adhesive systems had bond strength above the minimum for clinical routine use. As regards to bond strength, Transbond XT performed better than the resin cement and the flowable resin. Bond failure occurred within the adhesive in all groups.

A proporção áurea como complemento na determinação da dimensão vertical / The golden proportion as a method for the determination of complementary vertical dimension

O objetivo deste estudo foi avaliar se as medidas faciais utilizadas em métodos tradicionais para determinação da Dimensão Vertical de Oclusão estão em Proporção Áurea (1: 1,618) e, por conseguinte, se podem ser utilizadas como método complementar para determinação desta dimensão. Foram selecionados aleatoriamente pacientes entre 20 e 30 anos, da clínica de Odontologia da Universidade Estadual da Paraíba. A amostra foi composta por 30 indivíduos, sendo 15 do gênero masculino e 15 do gênero feminino. Através da análise de fotografias frontais destes indivíduos, e traçados que trespassam pontos cefalométricos, foi possível elucidar novas abordagens nos tratamentos de reabilitação oral. Em relação ao grau da DTM dos pacientes pesquisados, 63,3% (n = 19) apresentavam algum grau de DTM, sendo que 50% (n = 15) apresentavam DTM leve, 10% (n = 3) apresentavam DTM moderada e apenas 3,3% apresentavam DTM severa. O restante, 36,7% (n = 11), não apresentava sinais ou sintomas de disfunções de ATM. Podemos afirmar, através deste estudo, que em pacientes sem DTM tanto os métodos de mensuração facial como os métodos fisiológicos, como o de Litle modificado por Tamaki, são eficientes na determinação da Dimensão Vertical. Porém, em pacientes com disfunções, os métodos se mostraram imprecisos.

The purpose of this study was to evaluate whether the facial measures used in traditional methods of determination of the Occlusion Vertical Dimension are in Divine Proportion (1:1,618) and, subsequently, whether this Proportion can be used as a complementary method for determination of the dimension. For that, 20 to 30 year-old patients were selected at random from Odontology Clinics of the Paraíba State University. The sample was composed by 30 individuals, 15 of male gender and 15 female gender. Through the analysis of frontal photographs of these individuals, and the designs that trespass cephalometric points, it was possível to elucidate new approches on treatements of oral reabilitation. With regard to the degree of the Temple-mandible Disfunction, 63,3% (n=19) of the patients showed some degree of TMD, of whom 50% (n=15) showed mild TMD, 10% (n = 3) showed moderate TMD and only 3.3% showed severe TMD. The rest, 36.7% (n=11), did not show any signs or symptoms of TMA disfunctions. We can state that in patients without TMD, both the methods of facial measures and physiologic methods, such as Litle's Method modified by Tamaki, are efficient in the determination of the Vertical Dimension. However, in patients with TMD the physiologic methods were imprecise.

Incisivos Laterais Conóides: Otimização Estética Através do Uso de Resina Composta Direta / Connoid lateral incisors: esthetics optimization using direct composite resin

Na odontologia est�tica moderna, a realiza��o de reanatomiza��es de dentes con�ides apresenta-se como op��o de t�cnica para obten��o de um sorriso harm�nico. Nesse contexto, o avan�o dos materiais odontol�gicos diretos, como as resinas compostas e sistemas adesivos, permite a realiza��o desse procedimento de maneira simples e eficaz, quando comparado a outras t�cnicas dispon�veis. O presente trabalho mostra, atrav�s de um caso cl�nico, a possibilidade da realiza��o de um correto diagn�stico, planejamento e tratamento restaurador est�tico conservador, utilizando a resina composta como material restaurador direto, solucionando as anomalias de maneira simples, r�pida e econ�mica para o paciente.

In modern esthetic dentistry, recontouring peg-shaped teeth is an alternative technique for obtaining a harmonious smile. In this context, the advancement of direct dental materials, such as resin composites and adhesive systems, allows this procedure to be performed simply and efficiently, when compared with other available techniques. Through a clinic case, this study shows the possibility of achieving a correct diagnosis, planning and conservative aesthetic restorative treatment using composite resin as direct restorative material, thus solving quickly and cost effectively the teeth anomalies.