Dentistry Evaluation Of Single Unit Restoration Impressions - Term Paper Example

The concept of the use of impressions for prosthetic appliances construction goes back to the 18th century. Despite the fact that there are no historical records of the use of dental impression, a German surgeon, Matthaus Purmann (1648-1711) is noted to have held discussions on how sketches and wax models can be used for making prosthetic appliances (Bremner, 1958). Another German dentist called Philipp Pfaff (1713–1766) was the first to describe the impression taking procedure through the use of sealing wax softened with hot water to be later on filled with plaster of Paris for the formation of a rigid cast In 1787, an advertisement was run by John Greenwood in the New York Daily Advertiser stating that "individuals from any distance could be supplied with artificial teeth by simply sending an impression of their oral cavity taken by wax…” This advert appeared to be one of the earliest uses of modeling for the construction of dental prostheses.

In a letter to Dr. Jonathan Taft in 1861, Isaac John Greenwood, son of John Greenwood and grandson to Isaac Greenwood stated that neither his father nor grandfather who all practiced dentistry had used plaster of Paris when making models. He emphasized that they had used beeswax for their modeling. He went on further to state that together with his brother Clarke, they never used plaster of Paris up until 1820 (Weinberger, 1942). There are some impression materials that are suitable for use in dentistry.

Impression materials are important because they record intraoral structures to allow for the fabrication of definitive restorations. It is necessary that accurate impressions are made for the construction of dental prostheses. Impression taking for the duplication of tooth structures and oral conditions is a central procedure in prosthetic dentistry (Greenwood, 1861).   In 1819, in his ‘A Practical Guide to the Management of the Teeth’, Levis, S. Parmly stated that his procedure of making artificial teeth was an entirely new concept and would be perhaps one of the greatest achievements in dentistry.

He went on to further explain that, in instances where individuals had lost teeth in either or both their upper and lower jaws, artificial sets could be made by taking molds of all the depressions and the risings along the surface of the jaw before corresponding artificial sockets were made (Parmly, 1918.) The French Dentist C.F. Delabarre in 1820 introduced what is now known to be the first impression tray (Delabarre, 1820.) According to him, the softened wax had to be placed on a semi-elliptical cast of silver/white metal or in a small track and mounted on a handle or shaft on its front side as illustrated in Figure 1 above.

The impression tray was important because its walls helped to keep the pressure of the cheeks from wax by providing resistance. After the cast had been firmly pressed on, it would then be carefully removed and immersed in cold water to cool (Hoffmann-Axthelm, 1981.)