FAQs

1. How Safe Are Dental X-Rays?

Exposure to all sources of radiation — including the sun, minerals in the soil, appliances in your home, and dental X-rays — can damage the body’s tissues and cells and lead to the development of cancer. Fortunately, the dose of radiation you are exposed to during the taking of X-rays is extremely small.

Advances in dentistry over the years have lead to the low radiation levels emitted by dental X-rays. Some of the improvements are new digital X-ray machines that limit the radiation beam to the small area being X-rayed, higher speed X-ray films that require shorter exposure time compared with older film speeds to get the same results, and the use of film holders that keep the film in place in the mouth (which prevents the film from slipping and the need for repeat X-rays and additional radiation exposure). Also, the use of lead-lined, full-body aprons protects the body from stray radiation (though this is almost nonexistent with the modern dental X-ray machines.) In addition, federal law requires that X-ray machines be checked for accuracy and safety every two years, with some states requiring more frequent checks.

2. What are dental sealants, who should get them, and how long do they last?

Sealants are a thin, plastic coating that is painted on the chewing surfaces of teeth — usually the back teeth (the premolars, and molars) — to prevent tooth decay. The painted on liquid sealant quickly bonds into the depressions and groves of the teeth, forming a protective shield over the enamel of each tooth.

Typically, children should get sealants on their permanent molars and premolars as soon as these teeth come in. In this way, the dental sealants can protect the teeth through the cavity-prone years of ages 6 to 14. However, adults without decay or fillings in their molars can also benefit from sealants.

Sealants can protect the teeth from decay for many years, but they need to be checked for chipping or wear at regular dental check-ups.

3. What’s the latest word on the safety of amalgam-type fillings?

Over the past several years, concerns have been raised about silver-colored fillings, otherwise called amalgams. Because amalgams contain the toxic substance mercury, some people think that they are responsible for causing a number of diseases, including autism, Alzheimer’s disease, and multiple sclerosis.

The American Dental Association (ADA), the FDA, and numerous public health agencies say amalgams are safe, and that any link between mercury-based fillings and disease is unfounded. The cause of autism, Alzheimer’s disease, and multiple sclerosis remains unknown. Additionally, there is no solid, scientific evidence to back up the claim that if a person has amalgam fillings removed, he or she will be cured of these or any other diseases.

In March of 2002, the FDA reconfirmed the safety of amalgams. Although amalgams do contain mercury, when they are mixed with other metals, such as silver, copper, tin, and zinc, they form a stable alloy that dentists have used for more than 100 years to fill and preserve hundreds of millions of decayed teeth. The National Institutes of Health conducted several large-scale studies that concluded in 2006 that amalgam fillings were safe.

In addition, there has been concern over the release of a small amount of mercury vapor from these fillings, but according to the ADA, there is no scientific evidence that this small amount results in adverse health effects.

4. How do whitening toothpastes work and how effective are they?

All toothpastes help remove surface stains through the action of mild abrasives. Some whitening toothpastes contain gentle polishing or chemical agents that provide additional stain removal. Whitening toothpastes can help remove surface stains only and do not contain bleach; over-the-counter and professional whitening products contain hydrogen peroxide (a bleaching substance) that helps remove stains on the tooth surface as well as stains deep in the tooth. None of the home use whitening toothpastes can come even close to producing the bleaching effect you get from your dentist’s office through chair-side bleaching or power bleaching. Whitening toothpastes can lighten your tooth’s color by about one shade. In contrast, light-activated whitening conducted in your dentist’s office can make your teeth three to eight shades lighter.