The prevalence of tooth decay is improving at a population level but still affects one third of all five-year-old children in Wales as noted by Public Health Wales.
Mae nifer yr achosion o bydredd dannedd yn gwella ar lefel y boblogaeth ond mae'n dal i effeithio ar draean o'r holl blant pump oed yng Nghymru fel nodwyd ar wefan Iechyd Cyhoeddus Cymru.