Poor oral health, dental disease, and tooth pain can put kids at a serious disadvantage in school, according to a new Ostrow School of Dentistry of USC study.

"The Impact of Oral Health on the Academic Performance of Disadvantaged Children," appearing in the September 2012 issue of the American Journal of Public Health, examined nearly 1500 socioeconomically disadvantaged elementary and high school children in the Los Angeles Unified School District, matching their oral health status to their academic achievement and attendance records.

Ostrow researchers had previously documented that 73 percent of disadvantaged kids in Los Angeles have dental caries, the disease responsible for cavities in teeth. The new study shines light on the specific connection between oral health and performance in school for this population, said Roseann Mulligan, chair of the school's Division of Dental Public Health and Pediatric Dentistry and corresponding author of the study.

Children who reported having recent tooth pain were four times more likely to have a low grade point average - below the median GPA of 2.8 - when compared to children without oral pain, according to study results.

Poor oral health doesn't just appear to be connected to lower grades, Mulligan said, adding that dental problems also seem to cause more absences from school for kids and more missed work for parents.

"On average, elementary children missed a total of 6 days per year, and high school children missed 2.6 days. For elementary students, 2.1 days of missed school were due to dental problems, and high school students missed 2.3 days due to dental issues," she said. "That shows oral health problems are a very significant factor in school absences. Also, parents missed an average of 2.5 days of work per year to care for children with dental problems."

A factor in whether children miss school due to dental health issues was the accessibility of dental care. Eleven percent of children who had limited access to dental care - whether due to lack of insurance, lack of transportation, or other barriers - missed school due to their poor oral health, as opposed to only four percent of children who had easier access to dental care.