Health statistics from U.S. national health survey, series. B-14. Dental care, interval and frequency of visits. United States, July 1957-June 1959, statistics on time interval since last dental visit and frequency of dental visits during year by age, sex, residence, region, race, income, and education, based on data collected in household interviews during July 1957-June 1959; [prepared by Jane W. Bergsten].