Cyn i'r Cynllun Gwên gael ei lansio yn 2009, roedd gan hanner y plant pum mlwydd oed yng Nghymru bydredd dannedd ond, ers iddo gael ei lansio, mae hyn wedi gostwng i draean – ac mae pydredd dannedd yn effeithio ar tua 4,000 yn llai o blant pum mlwydd oed.
Before Designed to Smile launched in 2009 half of 5 year olds in Wales had tooth decay, since its introduction this has been reduced to a third – around 4,000 fewer 5 year olds having decay.