FRIDAY, Sept. 5, 2014 (HealthDay News) -- Parents and children in troubled families, where violence and verbal aggression are a common part of the daily landscape, tend to have more cavities and missing teeth, a new study suggests.

New York University researchers found that parents with worse oral health often had partners who were more verbally or physically hostile to them. And children whose mothers were emotionally aggressive to their fathers also had more decayed, missing or filled teeth.

Family oral health may suffer because "noxious" behaviors such as hitting, kicking, insults and threats create an emotional environment that undermines organized routines such as regular tooth brushing or promotes stress eating, according to the study, published in the September issue of the Journal of the American Dental Association.

"There's a pretty good history in the [medical] literature of lousy family environments being associated with bad health, so I guess our findings aren't surprising in that regard," said study author Michael Lorber. He's director of developmental research for the Family Translational Research Group at NYU's College of Dentistry.

"We had a really consistent set of findings that the more your partner is nasty to you, the more lesions are on your teeth," Lorber added.

Aggression is shockingly common in American families, with 90 percent of families in a 2005 study reporting parent-to-child aggression, couple aggression or both, the study authors said.

For the new study, Lorber and his colleagues analyzed 135 married or cohabiting heterosexual couples and their elementary school-aged children. They were mostly white, with an average annual income of $100,000.

Dental hygienists determined the number of decayed, missing or filled teeth through oral examinations, and subjective oral health was measured through questionnaires completed by both parents and children.

Parents also completed questionnaires about physical and emotional aggression between partners and between parents and children, along with harsh discipline. Additionally, observers rated the couples' hostile behavior in laboratory interactions.

On average, women had 3.5 additional dental cavities and men had 5.3 additional cavities for every above-average statistical increase in their partners' noxious behavior toward them, the investigators found. Children had an average of 1.9 additional cavities for every above-average increase in their mothers' emotional aggression toward their partners.

Lorber noted that in addition to disrupting healthy eating and oral health routines, noxious family environments may also impact the immune system, potentially leading to greater tooth decay.

"Maybe if you're fighting like cats and dogs, you're neglecting your teeth ... or eating more sugar and carbs," he said. "Certainly the immune system is also known not to function as well in hostile families. It's another way the family environment might impact oral health."

However, the study authors pointed out that their findings do not prove that toxic family behaviors cause poor oral health.

Dr. Jane Gillette, a dental researcher and dentist in private practice in Bozeman, Mont., said dentists could view poor oral health among their patients as a sign of a dysfunctional family dynamic.

"There are lots of ways we can intervene as health practitioners. We can recommend that families brush their teeth twice a day ... and eat healthy foods and floss," said Gillette, who is also a spokeswoman for the American Dental Association.

"But if you understand the family dynamic going on that might also be giving parents or children poor oral health, you can intervene that way, too," she added, "and connect them with appropriate resources in the community."

Lorber agreed.

"Dentists are kind of an underutilized point of contact for people, because a lot of people go to their dentists pretty regularly," Lorber said. "They're in a position to screen for a lot of things that might not otherwise get caught. We actually envision a future where a dentist would ask those kinds of questions."

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