Search

This study was undertaken in order to describe the occurrence of dental caries in Chinese schoolchildren and to highlight the oral health behaviour situation. Clinical examinations of grade 1 children (age 6, n = 381) and grade 6 children (age 12, n = 413) were performed. At age 6, 86 per cent of the children were affected by dental caries and at age 12 the mean DMFT index was 1.0. Personal interviews with the mothers (n = 691) showed that dental care habits of children were poor; 22 per cent of all children brushed their teeth twice a day and 20 per cent had seen the dentist within the past 12 months. Very few children (4 per cent) had practical support from their parents in daily toothcleaning. Self-administered questionnaires for schoolteachers (n = 138) revealed that most (85 per cent) are positive towards oral health education of children. Systematic school-based programmes should be implemented to promote oral health.

Objective: To explore the DNA damage of brain cells of rat after formaldehyde exposure. Methods: Rat brain cells were exposed to different concentrations of liquid formaldehyde (0.005, 0.025, 0.125 and 0.625 mmol/L) for lh. Single cell gel electrophoresis technique (comet assay) was used to test the DNA damage of the brain cells. Result: Formaldehyde could significantly cause DNA strands breakage at concentrations of 0.005 and 0.025 mmol/L while crosslinks were induced at concentrations of 0.125 and 0.625 mmol/L. Conclusions: Formaldehyde is the both a DNA strands breaker and crosslink agent to the brain in vivo.