Preschoolers across the country are increasingly getting fillings and extractions for extensive dental decay, sometimes requiring surgery and general anesthesia in an operating room, pediatric dentists report.

The trend, seen in families both rich and poor, points to neglect driven by several factors. Despite decades of emphasis on eliminating tooth decay with fluoride toothpastes and frequent brushing, many parents aren't getting the message that dental care begins when a child's first tooth comes in, and that a child should be brushing with fluoride by age 2.

Parents of all income levels indulge young children in too many sugary snacks and sippy cups filled with sugar-laden fruit juices, dentists say. Too often, they put toddlers to bed with a bottle of juice or milk. Saliva levels go down overnight, making the mouth even more acidic and allowing sugars in the drinks to eat into tooth enamel for hours at a time.

As a result, dentists are fighting more aggressively to counter the resulting decay, often treating cavities in baby teeth before the bad bacteria can spread elsewhere in the body or  harm the adult teeth forming below them in the jaw.

"The myth has been for years, these are just baby teeth, they're just going to fall out anyway," said Dr. Amr Moursi, chairman of pediatric dentistry at NYU's College of Dentistry. Moursi said the need for dental operating rooms at NYU exceeds the supply, forcing dentists to compete with cardiac surgeons and neurosurgeons for operating room time, and forcing patients to wait three to six months to have their dental surgeries scheduled. In addition, he said, it's hard to find  pediatric dentists with operating room privileges, which further squeezes the ability to treat children in need.

"There's not enough operating rooms in the country equipped to do dental work," he said.

Severe neglect of a child's oral health most often occurs among poor families "trying to make ends meet, pay the rent; it's not a high priority," Moursi said. However, dentists also are seeing a troublesome trend of lax parenting among more well-off mothers and fathers who don't enforce brushing-after-meals rules.

As parenting styles have shifted, there has been evidence of changes that "sometimes include a de-emphasis on oral health or anything that the child doesn't necessarily want, whether that's bath time, or practicing the piano, or eating their vegetables," Moursi said. "That's when we have the conversation: You're the parent and it's in their best interest. We give them some techniques to make it easier."

Just this morning, Dr. Jonathan D. Shenkin, a pediatric dentist in Augusta, Maine, found six small cavities between the teeth of a 4-year-old girl during her first-ever appointment with a dentist, who should have been seen by her first birthday. The girl's mother was at a loss to account for all the decay in her daughter's mouth, telling Shenkin that she thought she had her children doing everything right: "We don't drink soda. They brush their teeth twice a day."

But when he asked if the family uses fluoride toothpaste, she responded that they had just started to use it.

"Brushing with fluoride toothpaste is the most important thing you can do," he said. Next, parents must pay attention to what their children eat and drink. Numerous well-intentioned parents tell him they only give their children "all natural" products, thinking those somehow are better for their dental health. However, many fruit juices contain just as much sugar as sodas, he said.

Although dentists prefer to spend their time on prevention, a parent's decision to wait until a child is in pre-school before making a dental appointment is too late to prevent tooth decay that already may have begun, Shenkin said. "The kids coming into our offices at this age already have it at this point. There's no way to turn back."

"The goal should always be to treat in the office if possible," Shenkin said. "The last resort should be going into the operating room under general anesthesia."

By and large, the children going to the operating room tend to be lower-income children, he said. "When we talk about tooth decay, 80 percent of the disease is in 20 percent of the population … usually the lowest income population. The need for anesthesia disproportionately affects the Medicaid population."

Overall, he said, "we're seeing younger high-risk kids."

Although there aren't good statistics establishing the extent of pre-schoolers requiring extensive dental work, Moursi said he's seen a dramatic rise in the number of children with "really severe decay" warranting operating room treatment.

During an interview, he said he'd just received a phone call from an NYU pediatric dental resident who had examined a 4-year-old with several cavities, including one that had caused major facial swelling. "The infection had gone through the tooth, down into the surrounding bone of the jaw and spread up into the face under the eye," Moursi said.

The child was going to be treated with powerful antibiotics, but might still require a trip to the operating room to extract the tooth, he said. In rare cases, such dental infections can spread to the brain, or into the heart and lungs, he said.

"When you have a 6-month wait to get into the O.R. and they're all 3-year-olds, we know we have a problem," Moursi said.