The public increasingly demands straight, white teeth. Fillings for dental cavities used to be silver amalgam or gold. Now the aesthetic has been to use tooth-colored, off-white fillings. Some advantages and disadvantages are associated with using polymer-based white fillings. Polymers are also seen in dentures, bridges, crowns, impression materials and even in dental surgery as stints.
Polymer Challenge
A polymer is a long-chain chemical made up of smaller groups of chemicals called "monomers." Known in the industry as dental resins, the dilemma is to find a material to create dental materials that can go from freezing to near boiling and that can hold up in an acid environment, an environment full of bacteria and under extreme pressure. It also needs to be chemically stable, so its chemicals don't leach into the mouth.
White Fillings Made of Polymers
The substance used to fill cavities is glass or silica particles bound together with a polymer resin. This resin is often made out of metacrylic acid, according to the Royal Society of Chemistry, whose main objective is the advancement of the science of chemistry and its applications.
Dentures
Dentures are often made of polymers, usually methylmethacrylate. Previously, humans have tried the teeth of other humans or animals, wooden teeth, metal, and glass to form dentures. Polymers, while not without their problems, seem to be an improvement over all previous attempts.
Aesthetics
The new polymer addition to the patient's mouth can be matched with color and texture to the patient's own teeth. It can be used for fillings or dentures, and it is pliable enough that it can change the shape of an existing tooth. The new dentistry techniques give people more natural-looking teeth than anything used before.
Longevity
The polymer fillings do not last as long as the amalgam. Further, they are not as durable and generally not recommended for the tough duty of the back molars. They can also separate from the tooth. They do, however, require less of the tooth to be taken before they are used for fillings.
Questionable Substances
Metal amalgam for teeth is often made with mercury, which is dangerous to handle. But the polymers used in making artificial teeth sometimes contain bisphenol A. This chemical has been found to mimic estrogen. A 2000 study reported by the "Journal of the American Dental Association" found there were trace amounts of bisphenol A in the saliva of patients after certain dental procedures. A study reported by Informaworld.com, a website that provides specialist information, found that polymer dentures released formaldehyde. The state of California lists crystalline silica in composite resins as possibly causing cancer.
References
- Royal Society of Chemicals: Polymers in Everyday Things: Dentistry
- Professional Engineering Publishing: "Polymers in Dentistry"
- Informaworld: Release of Formaldehyde From Denture Base Polymers
- Dental Board of California: Facts About Fillings
- "Journal of the American Dental Association": Pharmacokinetics of Bisphenol A Released From a Dental Sealant; Eric Y. Fung, Ph.D.; 2000
