Effectiveness of Toothpaste Containing REFIX Technology against Dentin Hypersensitivity: A Randomized Clinical Study.

AIM: This clinical study aimed to evaluate the efficacy of a toothpaste containing a proprietary REFIX technology (Regenerador + Sensitive DentalClean, Rabbit Corp) against dentin hypersensitivity. MATERIALS AND METHODS: Fifty-three volunteers who fulfilled the inclusion criteria and signed the consent form were included. They were examined for dentin hypersensitivity. The participants received a 1-second blast of air, and the tooth sensitivity, from 0 to 10, was immediately evaluated using a visual analog scale (VAS). Then, the participants brushed their teeth with the multifunctional toothpaste, and dentin hypersensitivity was tested a second time using the same scale. The participants continued to use the toothpaste three times a day for 1 week, after which dentin hypersensitivity was recorded for the third time. Data were statistically analyzed using analysis of variance (ANOVA) and Tukey's test (α = 0.05). RESULTS: The mean patient age was 40 years, and 70% of the 53 subjects were female. There was a significant reduction in dentin hypersensitivity immediately after using the toothpaste and after 1 week. The baseline mean patient-reported pain score was severe (6.5 ± 2.4). Immediately after the first use of the toothpaste, the mean reported pain significantly decreased to mild pain (2.5 ± 2.5) (p < 0.05). After 1 week of consistent use of the toothpaste, the pain score reduced significantly (0.7 ± 1.2) (p < 0.05), and most participants reported no pain, demonstrating the effectiveness of the REFIX technology against dentin hypersensitivity. CONCLUSION: This clinical trial shows that the use of the phosphate-based desensitizing toothpaste containing REFIX technology significantly reduces dentin hypersensitivity after 1 week of consistent use. CLINICAL SIGNIFICANCE: The absence of pain, a desired clinical condition in patients with dentin hypersensitivity, was reached with the use of desensitizing toothpaste containing REFIX technology after 1 week of use. Such condition positively impacts quality of life, providing a healthier daily routine for patients.

Effect of two processing techniques used to manufacture lithium disilicate ceramics on the degree of conversion and microshear bond strength of resin cement.

The aim of the current study was to compare the effect of two lithium disilicate ceramic processing techniques (pressing and CAD/CAM) on the degree of conversion of resin cement when it is photoactivated and the microshear bond strength of resin cement to ceramics. Two ceramic discs were manufactured: one by the Press technique and another by CAD/CAM technique. Five Variolink Veneer resin cement samples were photoactivated through each ceramic disc and subjected to attenuated total reflectance Fourier transform infrared spectroscopy to evaluate their degree of conversion. To evaluate microshear bond strength, 20 ceramic bars were prepared: 10 using the Press technique and 10 using the CAD/CAM technique. The bars were air abraded with 50-µm Al2O3 particles, treated with 10% hydrofluoric acid for 20 s and subjected to RelyX Ceramic Primer application. Adper Scotchbond Multi-Purpose Adhesive was applied to the bars and cured for 10 s. Two 1-mm-height plastic tubes were placed on each bar and filled with Variolink Veneer resin cement. Each cylinder was cured for 20 s. Then the plastic tubes were removed and the microshear bond strength of each cylinder was tested. Data for degree of conversion (%) and microshear bond strength (MPa) were subjected to Student's t-test (α = 0.05). Both degree of conversion of resin cement photoactivated through ceramic and microshear bond strength of resin cement to ceramic were statistically higher in the group in which ceramic was prepared by CAD/CAM technique (44.74% and 22.18 MPa) than in the group in which the ceramic was prepared by the Press technique (25.71% and 19.83 MPa). The lithium disilicate ceramic processing techniques affected the degree of conversion of resin cement when it is photoactivated through the ceramics and the microshear bond strength of resin cement to ceramics.

O objetivo do presente estudo foi comparar o efeito de duas técnicas de processamento da cerâmica de dissilicato de lítio (prensada e CAD/CAM) no grau de conversão do cimento resinoso quando fotoativado e na resistência de união ao microcisalhamento do cimento resinoso às cerâmicas. Foram fabricados dois discos de cerâmica: um pela técnica prensada e outro pela técnica CAD/CAM. Cinco amostras de cimento resinoso Variolink Veneer foram fotoativadas através de cada disco cerâmico e submetidas à espectroscopia no infravermelho por transformada de Fourier com reflectância total para avaliar seu grau de conversão. Para avaliar a resistência de união ao microcisalhamento, foram preparadas 20 barras de cerâmicas: 10 utilizando a técnica prensada e 10 utilizando a técnica CAD/CAM. As barras foram tratadas com partículas de Al2O3 (50 µm), com ácido fluorídrico a 10% por 20 s e submetidas à aplicação do RelyX Ceramic Primer. Em seguida, o adesivo multiuso Adper Scotchbond foi aplicado nas barras e fotoativado por 10 s. Dois tubos de plástico de 1 mm de comprimento foram colocados em cada barra e preenchidos com cimento resinoso Variolink Veneer. Cada cilindro foi fotoativado por 20 s. Os tubos de plástico foram removidos e a resistência de união ao microcisalhamento de cada cilindro foi testada. Os dados de grau de conversão (%) e resistência de união ao microcisalhamento (MPa) foram submetidos ao teste t de Student (α = 0,05). Tanto o grau de conversão do cimento resinoso fotoativado através da cerâmica quanto a resistência de união do cimento resinoso à cerâmica foram estatisticamente maiores no grupo em que a cerâmica foi confeccionada pela técnica CAD/CAM (44,74% e 22,18 MPa) do que no grupo em que a cerâmica foi confeccionada pela técnica prensada (25,71% e 19,83 MPa). As técnicas de processamento de cerâmica dissilicada de lítio afetaram o grau de conversão do cimento resinoso quando fotoativado através das cerâmicas e a resistência de união do microcisalhamento do cimento resinoso às cerâmicas.