New Fluoride Technique May Reverse Some Cavities

A new way of applying fluoride to teeth could reverse small cavities, the American Dental Association has announced.

The new technique, which is being readied for tests on humans, makes the tooth enamel better able to react with and absorb fluoride, which prevents cavities.

It could be applied the same way fluoride is applied today -- in toothpaste, mouth rinses and gels, according to chemist Laurence C. Chow of the ADA's Paffenbarger Research Center in Chicago.

The new process uses calcium phosphate, which reacts with tooth enamel to form a natural mineral called dicalcium phosphate dihydrate. This in turn reacts with the fluoride, which bonds to the teeth in a form resistant to the wear and tear of saliva. When small cavities have begun to form, it can halt and reverse the process, the researchers said.

The process has worked on animals, and now Chow and his colleagues are waiting federal approval for a three-year study on humans. 8 Hours in Hospital Urged After Removal of Tonsils

Children who have their tonsils and adenoids out should stay in the hospital after the operation at least eight hours and sometimes even overnight, an Ohio surgeon recommends.

Hemorrhage can occur in up to 3.2 percent of cases, says Dr. Jeffrey S. Carithers, who reviewed the results of 2,944 such operations performed at Columbus Children's Hospital.

Such bleeding is easily handled in the hospital, but in patients who had been discharged, 19 percent required transfusions, he told a recent meeting of the Triological Society, an organization of ear, nose and throat doctors.

Many children also suffer recurrent vomiting, he said, which may lead to dehydration and require special nursing care to ensure the consumption of liquids. In the study, 15 percent of the patients needed this special care during their hospitalization.

More than 340,000 tonsillectomies and adenoidectomies are performed annually in the United States. Carithers says there is increasing pressure to cut costs and get patients home as quickly as possible. High Maternal Fever Suspected In Infants' Heart Defects

Eight out of 1,000 human babies are born with heart defects, and in 95 percent of the cases the cause is unknown. New research on chicken eggs provides a clue.

The eggs were placed in hot water, simulating a human fever, at various times before birth. Of those embryos that survived the heat, between 61 percent and 100 percent suffered heart defects, depending on how long they were submerged.

The experiment simulated human fevers of 105 degrees for periods of 19 to 27 hours in the first four weeks of pregnancy, Dr. Rene Arcilla of the University of Chicago told a recent meeting of the American Pediatric Society.

"Such high fevers are uncommon but not unheard of," he said. Further research may show whether lower fevers also can cause heart defects.

Chicken hearts develop in much the same way as human hearts, so they are commonly used as a model for study of the human heart. Researchers Update Photos Of Missing Children

If a 3- or 4-year-old child is abducted, what are the chances of recognizing the child years later from an old snapshot on a milk carton?

Not very good, says a Texas biomedical illustration expert who is using statistical growth data to bring old snapshots up to date.

Of 30 missing children sketched by Lewis Sadler of the University of Texas Health Science Center at Dallas and his associates, eight have been found. All had been abducted by one of their parents in a custody dispute.

The updated sketches are based on the growth patterns from data Sadler collected over five years. Forty-three points on the face -- and the distances between them -- are considered.

In two tests of the process on children who are not missing, the actual measurements matches the predictions 70 to 80 percent of the time, Sadler said -- close enough for a good visual match. "When you delve into the psychology of it, it actually turns out that we use just a small fraction of the information available" to recognize a face, he said. On the Pulse

The Food and Drug Administration has approved a new drug, Digibind, as an antidote for the commonly prescribed heart medicine digoxin, which can be lethal if an overdose is taken. About 175 deaths a year occur from accidental or intentional overdoses of digoxin, the FDA said, accounting for about half of all poisoning deaths in people over 60. Thousands of the 4 million people on digoxin suffer minor poisoning from the drug, which is derived from the poisonous digitalis plant . . . A shortage of bathrooms can lead to family stress, Psychology Today reports. In a survey of 200 Indiana households, half of those with only one bathroom said they suffered stress from a lack of privacy, compared with only 14 percent of those with two bathrooms. For comparison purposes, the households were matched for family size and number of rooms . . .