TY - BOOK ED - United States. Department of Health, Education, and Welfare. Public Health Service TI - Periodontal Disease and Oral Hygiene Among Children. United States T2 - Vital and Health Statistics.Series 11: Data from the National Health Survey, no. 117 PY - 1972/// CY - Rockville,Md. PB - National Center for Health Statistics N1 - Includes bibliographic references ER -