Dental caries is a widespread oral health issue in Asia, affecting an estimated 30% to 90% of children and adults. Many caries cases remain untreated, resulting in pain and infection. In response, the Asian Academy of Preventive Dentistry (AAPD) emphasises comprehensive caries management and organised a fluoride workshop at the 15th International Conference of the AAPD in 2023. The AAPD invited a group of experts to form a fluoride working group to review existing literature and develop fluoride recommendations for stakeholders across Asian countries and regions. The working group assessed caries risk and identified commonly used topical fluoride products for home care, professional, and community settings in Asia. The working group concluded that fluoride is a safe and highly effective strategy to reduce caries prevalence and incidence. The working group provided key recommendations based on successful regional caries management practices: (1) use topical fluoride for prevention and control of dental caries; (2) encourage the use of fluoride toothpaste with a concentration of at least 1,000 ppm for effective caries reduction; (3) advise a 0.05% fluoride mouth rinse as soon as children can spit it out to prevent early childhood caries; (4) deliver professionally administered fluoride, such as 5% sodium fluoride varnish, 2% fluoride gel, or 1.23% acidulated phosphate fluoride preparations, to decrease dental caries in at-risk individuals; and (5) apply 38% silver diamine fluoride to arrest cavitated caries. These recommendations aim to help practitioners, health care providers, and parents/caregivers make informed decisions about fluoride use as part of comprehensive oral health care in the region.
The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation1,2. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole3. Here we report images of M87 obtained in 2018, at a wavelength of 3.5 mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of [Formula: see text] Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3 mm. The outer edge at 3.5 mm is also larger than that at 1.3 mm. This larger and thicker ring indicates a substantial contribution from the accretion flow with absorption effects, in addition to the gravitationally lensed ring-like emission. The images show that the edge-brightened jet connects to the accretion flow of the black hole. Close to the black hole, the emission profile of the jet-launching region is wider than the expected profile of a black-hole-driven jet, suggesting the possible presence of a wind associated with the accretion flow.