Fillings and Crown/Bridge...

Dr. Pietrini writes a monthly column for Fra Noi, an Italian newspaper. Articles related to the topic of Fillings and Crown/Bridge are featured below. Click here to view this month's article

Don't Throw The Baby Out With The Bathwater by Dr. Pietrini
Last month I wrote about the history and use of silver/mercury (amalgam) fillings. When I graduated from dental school in 1970, there were basically two types of filling material available for the back teeth involved in chewing (the premolars and molars)-amalgam or gold. In the past thirty years because of advances in dental technology and the development of new restorative materials, the decision of what is the best filling material to use has become more complex and controversial. The term "standard of care" is used in dentistry to define what the majority of the profession believes to be safe and effective patient treatment. As new techniques and dental materials are developed, dental educators and clinicians rely on "evidence-based" research to support accepting these new advances as the standard of care; however, as older treatments and materials become outdated, it is not always necessary to throw the baby out with the bathwater.

For more than two hundred years the healthcare industry has known that over-exposure to mercury can have toxic effects. When amalgam was first used in dentistry and before mechanical mixing devices were available, dentists used to mix the silver and mercury compound by hand in a mortar and pestle and then they would place it in a squeeze cloth to wring out the excess mercury, often causing unnecessary spillage of the mercury. When accidental spills occur, mercury can get into carpeting or cracks and crevices in cabinetry resulting in possible toxic exposure to patients and dental personnel. Today, with the use of pre-measured capsules, mechanical mixing devices and safe disposal of excess mercury and amalgam scrape, accidents can be kept to a minimum.

A very vocal minority of healthcare professionals has made claims that amalgams can release toxic levels of mercury, which may be related to a variety of illnesses. There have been many attempts to have the government ban the use of amalgam. They claim that the mercury exposure may occur when fillings are placed, during chewing or when old amalgams are removed. The American Dental Association (ADA) and other credible health organizations believe that there is no reliable evidence-based research to support these claims. Some dentists have attempted to convince patients that removing old amalgam fillings will improve their health. At the very least the ADA considers this to be unethical. A few years ago, a patient who suffered from multiple sclerosis was promised that she would be cured of her disease if she had all of her amalgams removed. Since she could not afford the extensive dental rehabilitation that was recommended, she chose to have all of her teeth removed and replaced with dentures. When the condition of her health did not improve, she sued the dentist and his state dental board revoked his license.

Because of advances in dental technology and improvement of bonding materials in my practice, we have not been placing amalgam fillings for several years. On a personal note, I have several well-functioning amalgams in my mouth that were placed more than 45 years ago. I am in no hurry to have them replaced until it is necessary. The next time you require a new filling, discuss the treatment options with your dentist.

Like A Shiny New Penny by Dr. Pietrini
When I was in junior high school, a well-intentioned science teacher demonstrated what would happen if you dipped coins into mercury. The mercury reacted to the oxides on the surface of a tarnished penny and came out looking brand new. As is turns out the teacher needlessly exposed the class to the possible harmful effects of mercury, which can be toxic if it is accidentally inhaled or ingested. This will be the first article of a two discussing the history, uses and health concerns surrounding dental silver/mercury filling, which are called amalgams.

More than a thousand years before amalgam was used in Western civilization, the use of a "silver paste" was mentioned in Chinese literature. In the early 1800's, the use of silver/mercury fillings was common in France and England. In 1833, two Frenchmen named Crawcour came to the United States and began to market a crude form of amalgam, which they called "Royal Mineral Succedaneum." Silver shavings were cut from coins and mixed with mercury to form a paste. Many dentists were concerned that the amalgam expanded after setting protruding above the cavity preparation, often resulting in a poor bite or fracturing the tooth. They also were fearful of the possibility of mercurial poisoning. The American Society of Dental Surgeons required that its members sign a pledge not to use amalgam, but the advocates of amalgam eventually prevailed and the society disbanded in 1856. In 1859, the American Dental Society (ADA) was formed. About this time it was discovered that by adding tin to the silver/mercury paste the expansion could be controlled, so the ADA recommended amalgam as a safe and cost-effective filling material. By 1895, the mixture of metals in dental amalgam was modified to control both expansion and contraction. This basic formula remains the same today-a combination of about 50% mercury with an alloy of powdered silver, copper, tin and sometimes a small amount of other metals.

Because of fluorides, dental sealants and other preventive measures, there has been an increasing decline in cavities among children and young adults. Before 1970 the vast majority of dental restorations placed were amalgam fillings. By 1990, the number of amalgams placed was less than 50%. Approximately 70% of the restorations placed each year are replacements of worn or fractured fillings. Due to increased strength, cosmetics and reliability of composite (tooth-colored) filling materials, many dentists no longer use amalgam.

There are several reasons why millions of amalgam fillings will continue to be placed:
1. They are easy for dentists to place
2. Good longer-term reliability (can last more than fifty years)
3. Can be placed in less time than other materials
4. Unlike gold or some porcelain fillings, they can be completed in one visit
5. They are less expensive than other materials

Next month I will discuss some of the controversies surrounding the placement and removal of amalgam fillings.

Getting The Seal Of Approval by Dr. Pietrini
For more than forty years, the American Dental Association (ADA) has given its seal of approval for dozens of dental products and treatments. The ADA has given its full endorsement of the use of dental sealants for children and young adults. Past reports published in the Journal of the American Dental Association (JADA) indicate that 92 to 96 percent of sealants remain intact after one year, while up to 82 percent are in place after five years, yet less than 20 percent of American children have sealants on their teeth.

Dental sealants are thin plastic coatings that are applied to the chewing teeth-the permanent molars and premolars. These teeth have deep grooves and pits on the biting surfaces, which can trap food and bacteria. Fluorides found in toothpaste, drinking water and mouthwashes help to prevent decay on the smooth surfaces of teeth; however, they have less effect on the rough chewing surfaces. The vast majority of cavities occur in these areas. Sealants help to prevent decay from occurring or advancing by cutting off the oxygen supply that bacteria needs to convert sugary foods into acids, which break down tooth structure.

There are several ways to determine if a tooth needs a filling or a sealant:
· Visual examination
· Cavity detection dyes
· Removing stains with air-abrasion
· Cavity detection lasers

Sealants can be placed in the dental office by dentists, hygienists or properly certified dental assistants. After the grooves and pits in the tooth have been thoroughly cleaned with an abrasive powder, the tooth is rinsed and dried. Cotton rolls or gauze squares are placed around the tooth to keep it dry. A weak acid solution is placed on the tooth, which etches the surface of the tooth to provide a suitable surface for bonding the sealant. The tooth is rinsed and dried once again before the liquid sealant is placed on the grooves and pits and hardened with a laser or high-intensity curing light.

Dental sealants have become a cost effective way of preventing decay and loss of tooth structure. The fee for a sealant is about one-fourth the cost of the average bonded filling. Since the average filling lasts approximately 8-10 years, this becomes a substantial savings over the patient's lifetime. While there are no guarantees in health, using proper techniques, the success rate of sealants preventing tooth decay is so high, that our office is establishing a policy that if a sealant fails it will be replaced at no additional cost. If a cavity develops within a three-year period (provided the patient has had annual inspection of the sealants) the cost of the sealant will be deducted from the fee for the filling.