Teeth grinding turns out to be no more common in children with Down syndrome than it is in other children and it reduces with age. These are reassuring findings as teeth grinding can be quite an annoying problem at home and at school.
Buckley, S. (2007) Teeth grinding. Down Syndrome Research and Practice, 12(1), 16-16. doi:10.3104/updates.2048
Many children and adults grind their teeth and different studies report very different rates (from 7% - 88% for children) as Lopez-Perez and his colleagues note in a paper in this issue  . Teeth grinding can occur during the day and at night therefore parents and teachers are familiar with and may complain about this behavior. The research team report on the prevalence of teeth grinding (the technical term is bruxism) among children with Down syndrome in Mexico City. They report on the numbers of children who engage in teeth grinding and also ask if the numbers change with age, are different for boys or girls or vary with degree of intellectual disability. They also compare their findings with published studies to see if the pattern of teeth grinding in children with Down syndrome is the same as that reported for typically developing children.
They collected information for 57 children with Down syndrome, ranging in age from three to 14 years (34 boys and 23 girls). They examined the children's teeth and studied dental casts of their teeth to identify wear signs which indicate teeth grinding. They also asked parents to complete a questionnaire which asked about teeth grinding and other medical and health information. The children's degree of intellectual disability was taken from the records of the Center that they attended (The John Langdon Down Foundation).
They found that 42% of the whole group of children did grind their teeth. There was no difference in the rates for girls or boys and there was no evidence that rates varied with degree of disability (i.e. there was not more teeth grinding among the more disabled children). However, there was a link with age with the highest rate reported for the 6 years to 8 years 11 months group. The authors identify that this also seems to be the case for typically developing children and indicate that this is the age range for mixed dentition (having both first and second teeth). In the study reported and in other studies, the frequency of teeth grinding was less in preschool years and reduced as children got older than 9 years of age. Overall, the rates and the age pattern of teeth grinding seen in the children with Down syndrome was no different from those see in the typically developing children.
Parents, teachers and carers will be pleased to know that this behavior does reduce as children get older as it can be quite irritating when it is a daytime behavior. One further finding was that the eleven children with mosaic Down syndrome were significantly more likely to be teeth grinders than those with either standard trisomy or translocation forms. The authors do not speculate on why this might be the case.