Color changes of dental zirconia immersed in food and beverage containing water-soluble/lipid-soluble pigments

The present study examined color changes in the tooth-colored restorative materials, zirconia (3Y-TZP), resin composite, and porcelain. The colors (CIELab) of these materials were measured using a spectrophotometer. Specimens were immersed in black tea or curry for 1 and 7 days, after which colors were re-assessed. Color differences (∆E^*ab) before and after immersion were calculated. Specimens after the 7-day immersion were ultrasonically cleaned, and colors were measured again to assess the color recovery rate. The surface free energy, roughness, and water sorption/solubility of each material were also evaluated. Specimens were observed under a scanning electron microscope. The ∆E^*ab of 3Y-TZP was the smallest with both immersions. Resin composite had the smallest recovery rate. The surface free energy and roughness of 3Y-TZP were smaller than those of porcelain. 3Y-TZP and porcelain showed almost no sorption during the 7-day period. The present results revealed that 3Y-TZP exhibited the strongest resistance to discoloration.

Health benefits of 4,4-dimethyl phytosterols: an exploration beyond 4-desmethyl phytosterols

4,4-Dimethyl phytosterols possess two methyl groups at the carbon-4 atom of the aliphatic A-ring. The methyl groups are crucial for the molecular recognition of endogenous and exogenous bioactive compounds. Phytosterols have received worldwide attention owing to their recognized health benefits. However, 4,4-dimethyl phytosterols are less appreciated. Recent research studies revealed that 4,4-dimethyl phytosterols exert numerous beneficial effects on disease prevention, and are particularly involved in the endogenous cannabinoid system (ECS). The purpose of this review is to summarize and highlight the currently available information regarding the structures and sources of 4,4-dimethyl phytosterols, and to provide detailed preclinical studies performed to evaluate their potential for treating various diseases. Future research on 4,4-dimethyl phytosterols is warranted to confirm their relationship with the ECS, and to elucidate the mechanism directly toward clinical trials.

Nonglyceride Components of Edible Oils and Fats. 2. Nutritional and Health Significance

Edible oils and fats, which consist primarily of triglycerides of different fatty acids, also contain 1% to 10% of fat-soluble phytochemicals derived from oil-bearing seeds or fruits, collectively called the nonglyceride fraction. They belong to different classes of chemicals, each with a number of different chemical compounds. These chemicals are also present in the unsaponifiable fraction of oils and fats, some of them in a modified form. Several of these chemicals have been shown during the past two decades to have health-promoting functions, with vitamin, hypolipidemic, and antioxidant activities. Studies in experimental animals and humans have shown that they can have a preventive role in noncommunicable diseases, such as cancer, cardiovascular disease, and cataract. They also serve as a source of vitamin E and provitamin A. Thus, oils and fats in the nonglyceride fraction not only are sources of energy and essential fatty acids, but also have a disease-preventing and health-promoting role and can serve as a source of some fat-soluble vitamins. Certain edible oils, such as palm oil, rice bran oil, and sesame oil, are particularly rich in the health-promoting chemicals present in their nonglyceride fraction. Some of the edible unconventional oils have high levels of the nonglyceride fraction (8%–10%), and they may have important disease-preventing potential.