People have been paying more attention to the effects certain liquids like coffee, citrus-containing drinks, and even toothbrushes have on teeth. Mouthrinses are no exception. Mouthrinses contain essential oils, which include eucalyptol, menthol, thymol, alcohol, sorbitol, and others. People use mouthrinses for many reasons, ranging from whiter teeth, better breath, or cavity protection. But are there any risks to using mouthrinses that contain essential oils?

In a recent study in the November/December 2006 issue of General Dentistry, the Academy of General Dentistry's (AGD) clinical, peer-reviewed journal, authors examined mouthrinses containing essential oils and the effects they have on restorative materials in the mouth. Restorative materials studied in this article included amalgams (silver/mercury mixture used for fillings), glass ionomers (used to cement gold and ceramic crowns to teeth), and composite resins (fillers that are tooth-colored).

The authors subjected these materials to continuous exposure to mouth-rinses and distilled water for 10 days. The materials were placed in mouth guards that had three holes, each of which contained a specimen of each type of restorative material, and volunteer patients wore the mouth guards 12 hours per day for 10 days. The patients rinsed twice daily with a commercial mouthrinse and after the 10 days, the materials were removed from the devices and were inspected. Strength and appearance of the materials were observed and compared.

Overall the study found that even long-term exposure to a mouthrinse containing essential oils has a minimal effect on the strength or surface of dental restorations of any kind.

J. Anthony von Fraunhofer, PhD, the lead author of the study, says that "this is a positive finding since patients are often concerned that rinsing the mouth with alcohol-containing mouthwashes could affect their fillings. Fortunately, this was found not to be the case."

However, because many mouthrinses do contain a wide variety of ingredients, Dr. von Fraunhofer is looking to see whether they may have an effect on dentures and even orthodontic appliances. These studies are in progress and are yielding some interesting information. He indicated that he will report his findings to General Dentistry as they become available.

What are restorative materials?

•  Amalgams – silver/mercury mixture used for fillings
•  Glass ionomers – material used to cement gold and ceramic crowns to teeth
•  Composite resins – fillers that are tooth-colored