There is no such thing as two identical dentures! Dentures are unique objects, personalized for the individual use of each patient. They are made by filling a cast with acrylic resin and making later adjustments to the hardened dentures. The letter process is completed manually, and requires painstaking attention to detail; the manual adjustments performed in the end are meant to ensure a natural appearance of the false teeth as well as an optimum fit.
The initial diagnostic cast
During the patient’s visit to the dental office, the dentist or denturist makes an impression of the patient’s oral cavity; this is usually made in wax. The procedure consists in applying pressure to the soft tissue; the method usually involved bite simulation. The borders of the mold need to be extended to the toothless areas in order to get the exact shape of the patient’s gums. This impression is used to making the initial diagnostic cast.
The gypsum cast
Following the early adjustments performed on the initial cast, the shape needs to be replicated in gypsum. The gypsum cast can be also adjusted prior to the actual manufacturing of the dentures.
Filling the cast with acrylic resin
The denturist prepared the gypsum mold with a release agent meant to form a separating film between the acrylic resin and the model; this treatment is particularly useful during the later process of removing the hardened dentures from the mold. After applying the release agent, the mold is filled with an acrylic paste or liquid mixed by the denturist. When hardened, this mix will be the actual denture.
An alternative to using acrylic is porcelain.
The resin is packed and heated
Once the resin is places into the mold, the mold needs to be packed using a vise and heated for several hours (usually round eight hours) until the resin is caused to harden; after heating, the gypsum mold is broken open and removed; the dentures need to be smoothened for proper fit.
The denture just doesn’t fit?
Irrespective of how precise the finishing of these models is, the number of steps necessary to obtain the denture will allow certain errors. Should dentures not fit, the denturist will proceed to the necessary adjustments; some grinding and smoothing of the dentures by the dentist is usually enough to make it fit properly.
Quality control of the dentures
While taking the impression of the patient’s gums, these are caused to move, as they are soft tissue; as the gums move, there is always some place for errors and dentures may not fit perfectly. Additionally, in time, patient’s bones and gums shrink or change, causing the dentures to fit no more. Adjustments can include relining or rebasing the dentures to refit the current shape of the gums. Replacing or adding material to the saddle of the dentures is standard procedure and needs to be done every five to ten years.