The introduction of vulcanite in the 1850s was one of the revolutionary moments in the history of dentistry and orthodontics. Firm, durable, affordable and with the ability to be moulded to the patient’s mouth, it was a huge improvement on the ivory or precious metals previously used.

Charles Goodyear developed vulcanite, a hard vulcanised rubber, in 1843. In 1851 the production process was patented by his brother Nelson Goodyear. Vulcanite quickly became popular as a denture base material but the Goodyear Dental Vulcanite Company of Boston were relentless in enforcing its patent. Dentists using the material were required to purchase a license and pay royalties for each denture produced. The dental profession was extremely unhappy about this enforcement and fought the Goodyear Company in the courts. In 1876 the case made its way to the United States Supreme Court, which ultimately found in favour of the Goodyear Company who continued to enforce its patent. The aggressive enforcement campaign was led by the Company’s financial director Josiah Bacon, who was known to use spies, interviews with neighbours and intimidation to obtain evidence against dentists who supplied vulcanite dentures without a licence. In April 1879 Bacon’s pursuit had deadly consequences. Bacon was in San Francisco while investigating around 40 dentists, one of which was Samuel Chalfant. Bacon had successfully sued Chalfant twice before but each time, rather than paying the penalties, Chalfant abandoned his practice and moved to a new location. On Saturday 12th April Chalfant was once again successfully convicted of patent infringement. The next morning Chalfant went to Bacon’s hotel to confront him and a discussion ensued, during which Chalfant fatally shot Bacon. Chalfant went on the run for three days but eventually handed himself in. Despite support from many dentists during his trial, Chalfant was convicted of murder and was sentenced to 10 years in prison. On his release Chalfant returned to practising dentistry. After Bacon’s murder, the Goodyear company were less persistent in their enforcement of the patent, which expired two years later.

After the patent’s expiration in 1881 the use of vulcanite spread across the world. Starting out as a soft, malleable rubber surfer compound, vulcanite could be shaped onto a plaster model of the patient’s mouth. Once additional components had been added the vulcanite was cured in a vulcaniser which hardened the appliance through the application of heat and pressure.

Vulcanite was first used in orthodontics by the American dentist Norman Kingsley in 1859 when he constructed an artificial palate for a patient with a cleft palate. Vulcanite then started to be used for removable appliances and bite plates, held in place with simple ‘C’ clasps. Their construction allowed screws to be incorporated more easily. The museum’s collection contains several examples of these early appliances.

Vulcanite’s dark red colour was often left in orthodontic appliances, as it was suitable for use in the palate. Pink colouring could be added for its use in dentures but this weakened the rubber. Instead porcelain teeth with an added strip of pink porcelain gum were used to create a more natural look.

Acrylic was developed in 1928 and rose in popularity throughout the 1930s, replacing vulcanite in removable appliances and dentures.

Examples of early vulcanite removable appliances