A 28 month study of 1,227 ten-year olds in Belize found that xylitol-sweetened chewing gum was highly effective in preventing cavities and reversed the early stages of tooth decay, according to dental researchers at the University of Michigan. Another study of male patients at an Ohio Veterans Hospital suggests the sweetener may be an encouraging treatment for periodontitis (the gum disorder that is the chief cause of tooth loss in adults. The sweetener is produced commercially from birch wood and is similar to Sorbitol and regular sugar, but is chemically different enough to be less likely to promote the growth of decay-causing bacteria.