Japan’s health ministry will raise the government-set dental treatment remunerations that involve “silver” fillings containing palladium in May, as prices of the rare metal of which Russia is a major producer have soared following Moscow’s invasion of Ukraine, people familiar with the matter said Monday. The so-called silver fillings containing palladium and other metals are covered by the national health insurance, and remunerations dentists receive for treatment using them are reviewed four times a year — in January, April, July and October — due to fluctuating market prices for the materi…