The purpose of this study was to examine and compare color and translucency stability of three-dimensional (3D) printable dental materials for crown and bridge restorations. Five different materials were investigated, and twelve disc-shaped specimens of two different thicknesses (1 and 2 mm) were prepared using a digital light processing 3D printer. Color measurements were made according to the CIELAB color scale (L*, a*, and b*) using a spectrophotometer 1 h, 1 day, 1 week, one month, and six months after post-curing of the materials, and the translucency parameter (TP) was calculated. The L*, a*, b*, and TP values were compared among the different materials and storage periods using repeated measures analysis of variance. Color and translucency changes of the specimens after the different storage periods were compared with 1 h measurements to determine whether they exceeded clinically perceivable thresholds. The L*, a*, b*, and TP values showed significant differences according to the storage periods, as well as among the materials. Until one month, some materials demonstrated distinct color differences, while others showed small color differences below a clinically perceivable threshold. The translucency differences were not clinically perceivable for any specimen. After six months, all specimens demonstrated large color changes, whereas the changes in translucency were relatively small. In conclusion, the color of 3D printable dental materials changed with time, and the differences varied with the materials used. On the contrary, the changes in translucency were small. Overall, the materials became darker, more yellowish, and more opaque after six months of water storage.

SUMMARY: Objectives: The purpose of this study was to examine and compare the color and translucency of currently available resin-based composites (RBCs) with respect to the shade numbers within each product line. Methods and Materials: Four A-shades (A1, A2, A3, and A3.5) of nine RBC products (Beautifil II, Ceram-X One, Estelite Sigma Quick, Esthet-X HD, Filtek Z250, Filtek Z350 XT, Gradia Direct, Herculite Precis, and Tetric N-Ceram) were investigated. Ten disk-shaped specimens of two different thicknesses (1 and 2 mm) were prepared for each shade of the RBCs. The maximum blue light irradiance (Imax) through the specimen was recorded using a digital optometer. The color measurements were made according to the CIELAB color scale (quantifying L*, a*, and b*) using a colorimeter, and the translucency parameter (TP) was calculated. The L*, a*, b*, TP, and Imax values were compared among the different shades and thicknesses of each product using one-way analysis of variance followed by Tukey's post hoc test. Results: There were significant differences in the color and translucency among the shades and thicknesses within each product line (p<0.001). The L*, Imax, and TP of the 1-mm specimens were higher than those of the 2-mm specimens. The specimens showed equal or lower L* and Imax for higher shade numbers. The a* values differed only slightly among the shades, whereas the b* values were distributed over a relatively wide range. The TP values were independent of the order of shade numbers. Conclusions: Within the limitations of this study, the RBCs became darker and yellowish as the shade number increased. The blue light irradiance decreased in increasing order of the shade numbers. Changes in the translucency demonstrated different trends among the shades, depending on the product line.

Bacterial vaginosis (BV) is the most common disease in women of childbearing age and is caused by the growth of abnormal microbiota in the vagina. Probiotic consumption can be an effective alternative treatment to preserve or improve vaginal health. In the present study, MED-01, a complex of five strains of probiotic candidates isolated from the vagina of Korean women, was used. This study was designed as a 12-week, randomized, multicenter, double-blind, placebo-controlled clinical trial to evaluate the efficacy and safety of MED-01 on vaginal health. A total of 101 reproductive-aged women with a Nugent score of 4–6 took MED-01 (5.0 × 10⁹ CFU) or a placebo once a day, and 76 participants completed the procedure. MED-01 significantly reduced the Nugent score compared with the placebo. Quantitative PCR analysis confirmed that Lactobacillus plantarum was significantly increased in the vagina, whereas harmful bacteria such as Mobiluncus spp., Gardnerella vaginalis, and Atopobium vaginae were suppressed after 12 weeks of MED-01 ingestion. No adverse events to the test food supplements were observed in the participants. These results confirmed that MED-01 can be used as a probiotic for treating BV, as it improves the vaginal microbiota.