Scientists have found that combat veterans injured in certain brain regions are less likely to later develop post-traumatic stress disorder (PTSD). The findings suggest that PTSD might be treated by trying to reduce brain activity in these regions.

PTSD is a chronic anxiety disorder that affects millions of Americans. Many traumatic events can trigger it, including assault, rape, traffic accidents and military combat. People with PTSD relive their traumatic experiences through repeated nightmares and flashbacks that may seem real. They may become emotionally numb. They may startle easily and be constantly on guard.

NIH scientists and their colleagues studied how changes in the brain can affect PTSD. They analyzed brain scans from nearly 250 Vietnam War veterans who had been in combat. About 200 had received head wounds while fighting. The rest had no head injuries.

The researchers found that veterans rarely got PTSD if they had injuries in either of 2 brain regions. One region, the amygdala, plays a role in fear and anxiety. None of the 15 veterans with amygdala damage developed PTSD. The other brain region, a part of the prefrontal cortex, is involved in higher mental functions and planning. Only about 18% of veterans with damage to this region developed PTSD. In contrast, PTSD affected at least 40% of veterans with injury to other brain regions or no brain injury at all.

This study looked only at male veterans, but the scientists believe their findings might also apply to other types of people and trauma. Future PTSD treatments may try to suppress activity in the 2 brain regions, possibly through drugs or pacemaker-like devices.

When you eat or drink foods that contain sugar, germs in your mouth use the sugar to make acids. Over time, the acids can cause tooth decay, or cavities.

Fluoride in toothpaste and drinking water can protect the smooth surfaces of teeth, but back teeth need extra protection. Food and germs get stuck in their rough and uneven chewing surfaces, and toothbrush bristles can’t always get them clean. That’s where sealants come in.

Sealants are thin, plastic coatings painted on the chewing surfaces of back teeth to keep out germs and food. They prevent cavities from forming. And if a small cavity is accidentally covered by a sealant, the decay won’t spread because new germs are sealed out and germs trapped inside are sealed off from their food supply.

Many people still don’t know about sealants. In fact, only 30% of children in the United States have sealants on their teeth.

Children should get sealants on their permanent molars as soon as the teeth come in, before decay attacks them. Teenagers and young adults who are prone to decay may also need sealants. Sealants can save you time and money in the long run by helping you avoid the fillings, crowns and caps used to fix decayed teeth. Talk to your dentist about sealants for your family.