By Becca Newell
For anyone who’s donned the ever-flattering metalwork of aces, the uncomfortable, often nausea-inducing, process of teeth impressions is all too familiar.
Also used for teeth restorations and other dental work, the procedure involves a metal or plastic tray, filled with a viscous, putty-like solution, pushed into the upper or lower set of teeth. The trays cover the entire dental arch, including the roof of the mouth (with an upper tray) and under the tongue (with a lower tray). After a few minutes, the substance, commonly made of sodium alginate, polyether, and silicones, hardens and the trays are removed, presenting an inverse mold of the mouth.
Sometimes, the first impression attempt is unusable—the material has tears, void spots, or a host of other issues—subjecting the patient to the procedure all over again. If you’ve never had it done, it’s unpleasant and awkward. And, thankfully, no longer the only option.
Digital dental impressions offer a more efficient and much more comfortable alternative. There are no trays or gooey substances and it’s certainly less time-consuming. A full scan is completed within three to five minutes and patients aren’t left with distasteful impression remnants in between teeth and around the mouth.
“Digital dental impressions typically utilize either LED light or lasers to optically scan and record the surfaces of teeth and soft tissue to create a digital CAD (computer-aided design) file that can be utilized to create models or directly mill a definitive restoration,” says Dr. Scott Finlay, DDS, FAGD, FAACD, whose Arnold-based office has used this technology for more than seven years. “This digital file can then be uploaded to the dental laboratory to aid in the fa ication of the appliance or restoration.”
According to Finlay, current studies of this technology suggest digital impressions are as accurate, if not more so, than traditional impression techniques.
“In the past, when these impressions or models were shipped to a laboratory, they [may have been] exposed to extreme thermal changes and iatrogenic effects that [may have] compromised the accuracy of the models or impressions,” he says.
This method is eco-friendly, too, since it’s entirely electronic and eliminates the need for disposable trays and impression materials. Additionally, digital impressions contribute to efficient record-keeping because information can be stored electronically and accessed indefinitely.
Although the technology is worthy of its praises, there are some procedures where the traditional method is better suited, such as implant systems and removable dentures.
“Dental digital scanning systems are improving every day and it behooves the dentist to invest in this proven technology for the benefit and comfort of patients and to enhance the level of predictable care,” Finlay says. “Investment in this technology is an investment in the improvement in quality care for patients.”
Photo courtesy of Scott Finlay DDS
& Associates
The History of Dental Impressions
1819. In “A Practical Guide to the Management of the Teeth,” Dr. L. S. Parmly references a method of making artificial teeth by first producing a mold of the jaw. This is one of the first published mentions of dental impressions.
1839. In “The Dental Art: A Practical Treatise on Dental Surgery,” Baltimore-based dentist Chapin A. Harris, M.D., describes creating dental impressions by softening a piece of wax in warm water and pushing the substance into teeth and gums. After an impression is made, plaster of Paris is poured into the wax, which is later removed by heat to unveil the mold.
1886. E. T. Starr, of Philadelphia, patents an adjustable metal impression cup, similar in design to trays used today.
1911. G.H. Wilson publishes “A Manual of Dental Prosthetics,” in which he recommends Dr. Rupert E. Hall’s method of plaster impressions for full upper and lower teeth.
1925. Austrian inventor Alphons Poller patents “Nogacoll,” a material comprised of agar-agar and other reversible hydrocolloids. Soon after his death in 1931, almost a dozen competing ands appear on the market. This once fundamental ingredient, agar-agar, is no longer in use.
1965. Dental product manufacturer, ESPE, introduces the first polyether material specifically produced for use in dentistry. This substance is still used by dentists today.
1987. CEREC 1, by German engineering company Siemens, hits the market, enabling dentists to create a virtual impression via a 3D scanner and optical powder on the teeth.
