SYDNEY, Aug. 26 (Xinhua) -- Millions of cases of tooth decay could be prevented if Australia introduced a 20 percent tax on sugar, according to new research from Australia's Griffith University. The study estimated that such a tax could prevent 3.7 million cases of tooth decay, 191,000 cases of gum disease and 115,000 cases of complete tooth loss, Professor Lennert Veerman from Griffith's School of Medicine and