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Dental X-ray exposure in a group of New Zealand children.

The New Zealand School Dental Service provides dental care for children 2 1/2-13 yr of age, without using routine diagnostic radiographs. This study investigated the pattern of dental X-ray exposure in groups of New Zealand children. One group consisted of 100 children who had all treatment before the age of 13 years with the School Dental Service. The other group consisted of 82 children who were treated in the University of Otago School of Dentistry paedodontic programme. Children in both groups turned 13 years of age between 1977 and 1982. From age 13 years these children were cared for by contracting dentists. Radiographic histories were recorded from School of Dentistry charts, and from the area Principal Dental Officer. Cumulative radiation doses were calculated. Surfaces restored at age 13 were noted from Department of Health records. Results show that by age 13 children enrolled in the School of Dentistry paedodontic programme received a mean cumulative skin dose of 23.03 mSv. Thyroid dose was 0.242 mSv. Children treated in the School Dental Service received a mean cumulative skin dose of 1.01 mSv and a thyroid dose of 0.006 mSv. Cumulative radiation dose for both groups was low. There was no significant difference in the mean number of restorations placed at age 13 years despite an extremely low level of diagnostic radiography in the School Dental Service group.