We aimed to evaluate the color stability of bulk-fill and conventional composite resin with respect to thickness and storage media. Twenty specimens of a conventional composite resin (6 mm diameter and 2 mm thick) and 40 specimens of the bulk-fill Tetric EvoCeram composite resin at two different thicknesses (6 mm diameter and 2 mm thick or 4 mm thick, n = 20) were prepared. The specimens were stored in distilled water during the study period (28 d). Half of the specimens were remained in distilled water and the other half were immersed in coffee solution 20 min/d and kept in distilled water between the cycles. Color changes (ΔE) were measured using the CIE L ⁎ a ⁎ b ⁎ color space and a digital imaging system at 1, 7, 14, and 28 days of storage. Data were analyzed using Two-way ANOVA and Tukey's HSD post hoc test (P < 0.05). Composite resins showed significant increase in color changes by time (bulk-fill > conventional; P < 0.001). Coffee exhibited significantly more staining susceptibility than that of distilled water (P < 0.001). There was greater color changes with increasing the increment thickness, which was significant at 14 (P < 0.001) and 28 d (P < 0.01). Color change of bulk-fill composite resin was greater than that of the conventional one after coffee staining and is also a function of increment thicknesses.

In late December 2019, a new type of coronavirus, called novel coronavirus disease 2019 (COVID-19), caused a major outbreak of severe pneumonia in Wuhan (Huanan seafood market) and then, across China. As of 31 March 2020, COVID-19 has spread in 200 countries, including Iran, and imposed serious health-related threats to the public worldwide. Fever, dry (non-productive) cough, myalgia, and pneumonia seem to be the symptoms of COVID-19 disease. To date, and despite various studies and investigations, except for chloroquine and hydroxychloroquine, which have recently been temporarily approved by FDA, no other vaccines and/or antiviral agents have been clinically endorsed for the treatment of COVID-19 disease. Nevertheless, prevention of the disease and control of the infection is deemed a top priority for the general public. Owing to the characteristics of different dental treatments and settings, the risk of virus transmission can be considered high between patients and dental practitioners. Therefore, the need for strict and tough effective infection control protocols in dental practice is of great importance, namely for the dental centers in the potentially affected areas with COVID-19. This study, based on relevant evidence, aimed to review the basic knowledge of COVID-19 and address the recommended protocols of infection control for the dental practitioners and treatments in hypothetically stricken areas.

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When compared to placebo, preemptive oral analgesics are superior in achieving anesthetic success in inflamed pulp.