Abstract Introduction Composite resins are subject to challenges in the oral cavity that are related to patients' habits, which can compromise the restorations’ integrity and longevity. Therefore, it is necessary to study how consuming beverages and smoking cigarettes affects professional prophylaxis. Objective The aim of this study was to evaluate how the sodium bicarbonate air-polishing affects the mass change (sorption and solubility) of a composite resin exposed to cigarette smoke, red wine, or coffee solution. Material and method Eighty composite resin samples (FiltekZ350 XT - 3M/ESPE) were prepared and distributed into 8 groups (n=10): G1 (air-polishing + distilled water), G2 (air-polishing + coffee), G3 (air-polishing + red wine), G4 (air-polishing + cigarette smoke), G5 (distilled water), G6 (coffee), G7 (red wine), or G8 (cigarette smoke). The composite resin samples were weighed in triplicate to obtain M1 (initial mass), M2 (mass after 30 days of storage in the tested solutions), and M3 (after desiccation) values. The sorption and solubility values were calculated and analyzed using 2-way ANOVA and Tukey’s test (5%). Result The experimental groups had higher sorption and solubility values than the control groups, regardless of whether air-polishing was used. There was no statistically significant difference in the sorption between the air-polished and non-air-polished groups; however, the solubility was higher in the air-polished groups. Conclusion Air-polishing using sodium bicarbonate powder was able to intensify the solubility process of the tested resins but did not significantly increase the sorption values.

Resumo Introdução As resinas compostas estão sujeitas à desafios na cavidade oral relacionados aos hábitos dos pacientes, que podem comprometer a integridade e longevidade das restaurações. As consequências da associação do consumo de bebidas e o uso de cigarros à profilaxia profissional precisam ser estudadas. Objetivo O objetivo desse estudo foi avaliar como o jateamento com bicarbonato de sódio afeta a mudança de massa (sorção e solubilidade) de uma resina composta exposta à fumaça de cigarro, vinho tinto e café. Material e método Oitenta corpos-de-prova de resina composta (FiltekZ350 XT - 3M/ESPE) foram preparados e distribuídos em 8 grupos (n=10): G1 (jateamento + água destilada), G2 (jateamento + café), G3 (jateamento + vinho tinto), G4 (jateamento + fumaça de cigarro), G5 (água destilada), G6 (café), G7 (vinho tinto) e G8 (fumaça de cigarro). Os corpos-de-prova de resina composta foram pesados em três tempos diferentes para obter M1 (massa inicial), M2 (massa após 30 dias de armazenamento nas soluções testadas e exposição ao agente) e M3 (após dessecação). Os valores de sorção e solubilidade foram calculados e analisados usando ANOVA 2-fatores e teste Tukey (5%). Resultado Os grupos experimentais tiveram maior sorção e solubilidade comparado ao grupo controle, independentemente do uso do jateamento. Não houve diferença estatística na sorção para o fator jateamento. Porém, a solubilidade foi maior nos grupos jateados. Conclusão: O jateamento com bicarbonato de sódio foi capaz de intensificar a solubilidade da resina testada, embora não tenha aumentado significativamente os valores de sorção.

Abstract The aim of this study was to analyze the efficiency of experimental light-curing resin cements (ERCs) with a ternary photo-initiator system containing diphenyliodonium hexafluorphosphate (DPI) and different amines on retention of glass-fiber posts to dentin (GFP). ERCs formulations: a 1:1 mass ratio of 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenylpropane and triethyleneglycol dimethacrylate. Camphorquinone was used as initiator. Six experimental groups were established according to the amine used: [ethyl-4-(dimethylamino)benzoate-EDMAB or 2-(dimethylamino)ethyl methacrylate-DMAEMA] and the concentration of DPI (0, 0.5 mol%, 1 mol%). The resin cements Variolink II (dual- and light-cured versions) were used as commercial reference. Eighty recently extracted bovine incisors (n = 10) were selected for this study. The roots were prepared and the fiber posts were cemented with the resin cement specified for each experimental group. Specimens from coronal, middle, and apical thirds of the root were subjected to push-out bond strength test 24 hours after bonding. Data were subjected to split-plot ANOVA and the Tukey test (p = 0.05). ERCs containing DPI showed statistically significant higher bond strengths compared with ERCs without DPI. ERCs containing DPI were statistically similar to VARIOLINK II – dual-cured and superior to VARIOLINK II – light-cured (except for EDMAB – 1DPI in the medium third and DMAEMA – 1DPI in the coronal third). Different amines did not influence post retention. The apical root region showed the lowest bond strength for the groups EDAB-0DPI, DMAEMA-0DPI and VARIOLINK II light-cured. Light-cured ERCs containing DPI were efficient for GFP retention to radicular dentin, with similar behaviour to that of dual-curing commercial resin cement.

AIM: This in vitro study evaluated the effect of using a dental hypersensitivity treatment on the bond strength to dentin of etch-and-rinse and self-etching simplified adhesive systems. METHODS: 40 healthy molars were used. The crowns of teeth were removed at the dentinoenamel junction, and remaining roots were sectioned in the mesiodistal direction along their long axis, separating the buccal and lingual/palatal halves. The segments obtained were ground, keeping the buccal or lingual/palatal face turned downwards in order to flatten the surface and produce a standardized smear layer. Prepared specimens were randomly distributed into 4 groups (n=10), according to the combination of surface treatment with the desensitizing dentifrice Colgate Sensitive Pro-Relief (Colgate Palmolive®) (test group - with dentifrice and control group - without dentifrice) and type of simplified bonding agent (etch-and-rinse and self-etching agents). Resin composite blocks were fabricated on the dentin surfaces, after application of bonding agents, and specimens were sectioned into rectangular stick-shaped specimens with cross-sectional area of approximately 0.8mm². For microtensile bond strength tests, 4 sticks were randomly selected from the central region of specimens, and fixed to a universal test machine. Data were analyzed statistically by the Mann-Whitney U test (a=0.05). RESULTS: The bond strength obtained in the group without desensitizer (control) + etch-and-rinse agent was significantly higher compared with the other groups. Under both experimental conditions, the self-etching agent showed weak bond strength to dentin. CONCLUSIONS: Change in the dentin substrate by obliteration of tubules in the process of relieving dentinal sensitivity could reduce the bond strength of simplified etch-and-rinse and self-etching bonding agents.

The aim of this study was to evaluate the degree of conversion (DC) of two composite resins with different shades that were light cured by light-emitting diodes (LEDs) of different irradiances. Specimens (5 mm ' 2 mm) were prepared with a nanofilled (Filtek Supreme - A2E, A2D, and WE) or microhybrid resin (Opallis - A2E, A2D, and EBleach Low) and were randomly divided into 12 groups (n = 5 each) according to the composite resin and light-curing unit (Elipar FreeLight 2, 1250 mW/cm²; Ultralume 5, 850 mW/cm²). After 24 h, the DC was measured on two surfaces (top and bottom) with Fourier Transform infrared spectroscopy (FTIR). Data were statistically analyzed with two-way ANOVA and Tukey test (a = 0.05). Statistical differences among the surfaces were observed in all experimental conditions, with higher values on the top surface. The microhybrid resin presented the highest DCs for shades A2E and A2D on the top surface. The LED with higher irradiance promoted better DCs. Taken together, the data indicate that the shade of a composite resin and the irradiance of the light source affect the monomeric conversion of the restorative material.

OBJECTIVES: The aim of the present study was to assess the effect of the exposure to food-simulating liquids prior to brushing simulation on the surface roughness of five composite materials (Quixfil, Filtek Supreme, Esthet-X, Filtek Z250, Tetric Ceram). Material and METHODS: Twenty cylinders (5 mm diameter and 4 mm height) of each composite were randomly allocated to 4 groups (n=5), according to the food-simulating liquid in which they were immersed for 7 days at 37°C: artificial saliva, heptane, citric acid, and ethanol. After this period, the top surface of composite cylinders was submitted to 7,500 brushing cycles (200 g load). Measurements of the surface roughness (Ra, ¼m) were carried out before and after the exposure to the chemicals/brushing simulation. Changes on the morphology of composite surfaces were observed through scanning electron microscopy (SEM). RESULTS: The statistical analysis (ANOVA with cofactor / Tukey's test, α=5%) detected a significant interaction between solutions and composite resins. Esthet-X, Filtek Z250 and Tetric Ceram were not affected by the food-simulating liquids/toothbrushing. Citric acid and ethanol increased the surface roughness of Quixfil and Filtek Supreme, respectively. SEM images corroborate the surface roughness findings, demonstrating the negative effect from chemical solutions and mechanical abrasion. CONCLUSIONS: The surface roughness of composite resin materials are differently affected by the food-simulating solutions, depending on the immersion media.

Statistical analysis interpretation is a critical field in scientifc research. When there is more than one main variable being studied in a research, the effect of the interaction between those variables is fundamental on experiments discussion. However, some doubts can occur when the p-value of the interaction is greater than the signifcance level. OBJECTIVE: To determine the most adequate interpretation for factorial experiments with p-values of the interaction nearly higher than the signifcance level. MATERIALS AND METHODS: The p-values of the interactions found in two restorative dentistry experiments (0.053 and 0.068) were interpreted in two distinct ways: considering the interaction as not signifcant and as signifcant. RESULTS: Different findings were observed between the two analyses, and studies results became more coherent when the signifcant interaction was used. CONCLUSION: The p-value of the interaction between main variables must be analyzed with caution because it can change the outcomes of research studies. Researchers are strongly advised to interpret carefully the results of their statistical analysis in order to discuss the findings of their experiments properly.

O objetivo do presente estudo foi avaliar o efeito de diferentes sistemas adesivos sobre a microinfiltração na interface de reparos em resina composta. Corpos-de-prova do compósito Filtek Z250 (3M-ESPE) foram divididos aleatoriamente em cinco grupos (n=20) de acordo com a forma de confecção do reparo: C - controle - condicionamento com ácido fosfórico a 35%; SB1 - condicionamento ácido e aplicação de uma camada do agente de união Single Bond (3M-ESPE); SB2 - condicionamento ácido e aplicação de duas camadas de Single Bond; SMP1 - condicionamento ácido, aplicação do primer e do adesivo do sistema Scotchbond Multipurpose Plus (3M-ESPE) e SMP2 - condicionamento ácido e aplicação apenas do adesivo do ultimo sistema. O reparo foi finalizado com a inserção de nova camada do compósito restaurador. As amostras foram termocicladas (500 ciclos / 5-55°C [±2]) e imersas por 4h em solução tamponada de azul de metileno 2% (pH 7,0). A penetração do corante na interface do reparo foi avaliada em lupa estereoscópica (40x) por três examinadores utilizando quatro escores representativos. A análise estatística não encontrou diferenças entre os grupos experimentais (Kruskal-Wallis / p > 0.05). Dessa maneira, os diferentes sistemas adesivos mostraram comportamento semelhante sobre a microinfiltração na interface do reparo.

The purpose of the present study was to evaluate the microleakage at the composite-repair interface using different bonding systems. Composite resin specimens (Filtek Z250 - 3M-ESPE) were divided into five groups (n=20) according to the following bonding mechanism: C - control - etching with 35% phosphoric acid; SB1 - etching and application of one coat of Single Bond (3M-ESPE); SB2 - etching and application of two coats of Single Bond (3M-ESPE); SMP1 - etching, application of Scotchbond Multi-Purpose primer (3M-ESPE) followed by the adhesive and, SMP2 - etching, application of Scotchbond Multi-Purpose adhesive (3M-ESPE) without the primer. Thereafter, all groups received new resin application. Samples were thermocycled (500 cycles / 5ºC - 55ºC [±2]) and immersed for 4h in 2% methylene blue buffered dye solution (7.0 pH). Three examiners measured the extent of microleakage in a stereoscope microscope, using four representative scores. For all experimental groups, no significant difference in microleakage at the repair was identified by Kruskal-Wallis test (p > 0.05). Therefore, different types of bonding systems presented the same effect on the dye penetration along the repair interface.