Evolution of Materials in Dental Fillings

By Arya Bhatt

Published 2:03 EST, Weds December 29th, 2021

Dental materials are essential in numerous treatments including plaque removal, fillings, aesthetic interventions, and more. For thousands of years, the types and uses of dental materials have adapted and evolved as technology has improved and better materials have been discovered and formed to provide the best care for the patient.

One use of dental materials is in tooth fillings where a cavity in the tooth has to be repaired by filling in a hole to ensure further decay does not occur whilst achieving aesthetic quality for the patient. The earliest evidence of fillings dates back over 13,000 years ago where the remains of a person who lived in what is known now as northern Italy has been found to have sizeable holes in their teeth with evidence of some drilling. The report from 2017 included that there was evidence of bitumen, a tar-like substance, to fill the teeth. Using bitumen for fillings in the 21^st century would not only be unsuccessful but uncomfortable for the patient too.

Furthermore, the oldest surviving dental fillings date back to approximately 6500 years ago where a cracked canine tooth was discovered to have beeswax filling and was discovered by researchers in 2012. In addition, the use of gold in dentistry also dates back thousands of years where gold crowns were utilized in the year 201. Gold fillings began to be utilized in the 1800s due to their soft nature and making it easy to fill cavities. Today, gold fillings are possible but are much more expensive and more noticeable compared to other alternatives.

Still, in use today is the use of amalgam fillings which first appeared to be used in the year 659 in China and a written formula was also published in China by the year 1505. Modern amalgams were introduced in the 1800s where small amounts of mercury were added to silver and in 1806, French dentist Auguste Taveau used this material as a dental restorative and filler. At this time, this dental filler included some practical issues as it tended to expand significantly after setting. However, mercury is soft enough to mold effectively whilst setting hard and lasting for a long duration after curing. This composition of amalgam has slightly changed over the years since the 1800s and nowadays contains mercury, silver, tin, and copper.

But one controversy that still exists today involved the risks of mercury in amalgam fillings. The effects of mercury on the body are seen to be devastating and some argue that even though only very minute amounts of vapor are present, amalgam fillings should no longer be used. Some autopsy studies from people with amalgam fillings have shown that individuals with amalgam have toxic levels of mercury in their brains or kidneys. However, the US FDA has stated that in most cases, dental amalgam does not lead to negative health effects but may pose a greater risk in certain groups, such as pregnant women and those with impaired kidney function. The UK’s NHS states that mercury from amalgam fillings does not have any harmful effects on health. Overall, there may be some evidence found that some harmful effects may occur but currently there is not sufficient evidence to make a clear claim or to make amalgam banned from use in dental fillings.

The most popular filling material for a variety of reasons today is composite. These fillings are made up of powdered glass quartz, silica, or other ceramic particles which are then added to a resin base. This filling material is built up in layers and set with UV blue light. One of the many advantages of this material is that it matches with the color of the tooth making it a better aesthetic choice for patients. Even though they are very durable, amalgam fillings are seen to have a longer lifespan within the mouth and composite fillings are more expensive and require a longer procedure by the dentist to put in place. At the same time, many patients are put off by amalgam due to the metallic look which isn’t natural.

In regards to the future, there are already some excellent materials being developed to make fillings even more effective. New composites, made of bioactive glass, help repair tooth decay through the release of fluoride, calcium, and phosphate. Standard amalgam and composite fillings just fill the cavity but these new composites replenish minerals to form new tooth material and prevent oral bacteria from infiltrating the tooth further.

Overall, the use of dental materials in fillings has developed over many years, with the sole purpose to improve the quality of the fillings for the patient. As new materials have been tried and tested over time, it is evident that some are better than others in their own ways but at the end of the day it is the patient’s choice and it is in the dentist’s best interest to help the patient and fix their cavity.

Arya Bhatt, Youth Medical Journal 2021

References:

Levine, N., 2021. The History of Dental Filling Materials from Prehistoric to Modern Times. (online) Dental Products Report. Available at: https://www.dentalproductsreport.com/view/the-history-of-dental-filling-materials-from-prehistoric-to-modern-times?page=4

Caring Tree Children’s Dentistry. 2015. The History of Dental Amalgams – How They Have Changed Over Time. (online) Available at: https://www.caringtreechildrensdentistry.com/blog/the-history-of-dental-amalgams/

Mutter, J., 2011. Is dental amalgam safe for humans? The opinion of the scientific committee of the European Commission. (online) Dental Products Report. Available at: https://www.dentalproductsreport.com/view/new-dental-fillings-could-actually-repair-tooth-decay

U.S. Food and Drug Administration. 2021. Dental Amalgam Fillings. (online) Available at: https://www.fda.gov/medical-devices/dental-devices/dental-amalgam-fillings#:~:text=The%20majority%20of%20evidence%20shows,effects%20generally%20associated%20with%20mercury.

Archibald, J., 2021. What You Should Know About Composite Fillings. (online) Healthline. Available at: https://www.healthline.com/health/dental-and-oral-health/composite-fillings#procedure