ABSTRACT
OBJECTIVES: This study aimed to assess the effect of an optical whitening toothpaste on color stability of microhybrid, nanofilled, and microfilled composite resins and resin-modified glass ionomer (RMGI) cement in comparison of two other toothpastes. MATERIALS AND METHODS: In this experimental study, disc-shaped composite samples were fabricated. The samples were then polished using silicon carbide papers. Twenty-seven samples of each material were fabricated and subjected to colorimetry using a spectrophotometer. Each group of material was then divided into three subgroups for the application of conventional whitening and whitening containing blue covarine toothpastes. One operator brushed the samples with an electric soft toothbrush with circular motion twice a day, each time for 30 seconds. Colorimetry was performed at 0, 1, 7, 30, and 90 days. STATISTICAL ANALYSIS: Two-way analysis of variance (ANOVA), one-way ANOVA, and Tukey's honestly significant difference (HSD) test were used for statistical analysis. RESULTS: The interaction effect of type of restorative material and time on ∆E was not significant at baseline or 1 day (p > 0.05). The effect of type of toothpaste on ∆E was not significant at baseline or 1 day (p = 0.78) but the effect of type of material was significant (p < 0.05). The toothpastes had significantly different effects on ∆E of Z250 at all time points (p < 0.05) except for ∆E0-30 (p = 0.106). The toothpastes had significantly different effects on ∆E of Z350 and Gradia at all time points (p < 0.05). The same was true for RMGI except for ∆E0-7 (p = 0.43) and ∆E0-90 (p = 0.52). The majority of color changes caused by toothpastes were not clinically perceivable (∆E < 3.3), except for ∆E0-90 by the whitening toothpaste (∆E = 9), ∆E0-90 by the conventional toothpaste for Z350 (∆E = 3.9), and ∆E0-1 by the whitening toothpaste for RMGI (∆E = 3.7). CONCLUSION: The color change of all composite samples was not clinically perceivable (<3.3) at all time points, which shows that the tested toothpastes do not cause a significant change in color of composite materials.
ABSTRACT
The purpose of research was comparing the ultrasound (US) features and fine-needle aspiration cytology (FNAC) in detecting the thyroid nodules in clinical practice. A cross-sectional analytical study retrospectively reviewed the US and FNAC findings for a total of 170 thyroid nodules. The US features that we compared included echogenicity, calcifications, shape, halo and Doppler, between 2017 and 2018. Totally, 170 nodules of thyroid were studied, which contained 72 (42.4%) benign and 98 (57.6%) malignant thyroid nodules. The sonographic features were significantly associated with malignancy such as microcalcification (97.0%), hyperechogenicity (91.5%), wider than taller shape (98.0%), absent halo (90.9%) and positive Doppler (78.0%) (P < 0.01). The altogether accuracies of calcification, echogenicity, shape, halo, and Doppler were 0.96, 0.92, 0.97,0.82 and 0.82, respectively. Our data suggest that US features could be a good sonographic criterion for recommending FNA cytology with follow-up thyroid sonography and FNA.
