A two-year-old Latina child's mouth was aching and she was quietly crying herself to sleep. But the pain, disease and enormous costs of treatment for her tooth decay were all preventable, according to scientists at the University of California, San Francisco School of Dentistry.

In a recent study published in The Journal of Clinical Pediatric Dentistry, clinicians and researchers teamed together to study bacterial, behavioral and environmental factors associated with Early Childhood Caries (ECC or baby bottle tooth decay). They found that ECC is a preventable condition characterized by decay of primary (baby) teeth which may begin as an infant's teeth erupt, long before her first year. What is also significant is that the two-year-old was probably infected by her own mother's mouth bacteria due to lack of dental health care in underserved and poor communities, the study found.

ECC is five times more common than asthma and seven times more common than hay fever, but researchers are just beginning to understand its complexity.

In the UCSF study, researchers assessed salivary levels of the bacteria mutans streptococci (MS) and lactobacilli (LB) in underserved, predominantly Hispanic children. One hundred forty-six infants and toddlers aged three to 55 months with dental decay were identified and examined. The study demonstrated significant association between relatively low cariogenic bacterial levels and dental caries in infants and toddlers. The same bacteria strain (MS or LB) of the mother or caretaker was found in the infants and toddlers. The study also showed that ECC correlates significantly with the child's age and lack of dental insurance of the children and that ECC also correlates with both low family income and the less education of the mother of the child.

Francisco Ramos-Gomez, DDS, MSc, MPH, UCSF associate professor of pediatric dentistry in the department of growth and development and director of the Pediatric Dental Services at San Francisco General Hospital Medical Center, is lead author of the study. "This population needs help from all of us; from policy makers, health care providers and from those serving the children," Ramos-Gomez said. "The cost of a full mouth rehabilitation under general anesthesia of a two year old is about $10,000. If we can make an impact on the population by teaching them directly how to care for their infants before the damage is done, we can save the children from the pain and society from the costs of repairing the decay."

Most people don't realize the importance of baby teeth, Ramos-Gomez said. They affect the oral health of an adult by

- Guiding permanent teeth and preventing decay and malocclusions

- Chewing food, which could affect adults through eating disorders and gastrointestinal problems - Speech development patterns

- Passing bacteria to permanent teeth

Oral health also affects the children when they are sleeping, during daily play and learning as well as having self-esteem.

Study subjects were recruited from three sites based at the SFGH Medical Center (the Family Dental Center; the Women, Infant and Children Program (WIC), and the Well Child Clinic). All of these sites serve primarily low-income Hispanic and African-American families.

The population studied included the following demographics:

- All of the children were from San Francisco

- 45 percent were female; 55 percent were male

- The median age was 30 months (range from 3 months to 55 months)

- 137 were of Hispanic origin (Mexican, Mexican-American, Central American or from Puerto Rico)

- Two were African American and four were non-Hispanic whites

- 15 percent of the children were from single-parent families

- 95 percent of caregivers were mothers; 4 percent were fathers and 1 percent were other relatives

- Median age of the mothers was 27 years

- Median age of the fathers was 28 years

- 73 percent of parents had less than a high school education

- 71 percent of families earned less than $15,000 annually

The majority of parents (55 percent) had not seen a dentist in the previous two years, but 79 percent reported they currently had tooth decay.

Dental caries in preschool children remain a significant health problem in the United States. The prevalence of caries is especially high among low-income children, particularly Native Americans, Mexican-Americans and African Americans. "

There was a statistically significant correlation between ECC and lack of dental insurance of the children," Ramos-Gomez said. Children without dental insurance were more than twice as likely to have EDCC as children with dental insurance.

"The most striking finding of our study was the low levels of MS bacteria associated with ECC in very young children," Ramos-Gomez said. "This finding may put these infants and toddlers at higher risk than previously thought." In these young children, threshold levels of both bacteria associated with caries were lower than in older children and adults, meaning that infants and toddlers are more at risk.

Efforts to reduce ECC should include improving dental education and access to dental care for adult caregivers. The UCSF research suggests that these two factors could significantly reduce transmission of MS from adult to child.

"Our study has been validated recently by two papers which confirmed that baby' s mouths can be colonized with cariogenic (decay causing) bacteria before their teeth emerge," John D.B. Featherstone, PhD, said. Featherstone, UCSF professor and chair of the department of preventive and restorative dental sciences, added that the UCSF study found that the levels of bacteria for infants that cause the beginnings of decay are very low compared to older children and adults. "Unfortunately," he said, "the lack of oral health of the mother or caregiver seems to perpetuate itself with these youngsters."

Co-authors of the study include Jane A. Weintraub, DDS, MPH and Stuart A. Gansky, DDS, both UCSF professors of preventative and restorative dental sciences; Charles I. Hoover, PhD, UCSF assistant professor of stomatology; and John D.B. Featherstone, PhD, UCSF professor and chair, preventive and restorative dental sciences. This study was funded by a grant from the National Institute of Dental and Craniofacial Research.