title: Letter: On the P/O index.
mesh_terms: D004245:DMF Index; D003818:Dentition, Mixed; D006801:Humans; D008310:Malocclusion / Q000145:classification / Q000453:epidemiology* / Q000628:therapy; D009970:Orthodontics / Q000600:supply & distribution*; D010512:Periodontal Index