Dentures are removable devices designed to replace missing teeth and the surrounding soft and hard tissues. Creating a comfortable, functional, and aesthetically pleasing denture involves a precise, multi-stage process. This procedure requires close collaboration between the dental office and the specialized laboratory to ensure the appliance is custom-fitted to the patient’s unique anatomy.
Initial Assessment and Impression Taking
The process begins with a thorough clinical assessment to evaluate the patient’s oral health and determine the denture requirements. The dental professional takes a preliminary impression using a stock tray and a material such as alginate. This initial impression captures a basic, low-detail mold of the jaw ridge and surrounding tissues.
The preliminary mold is sent to the laboratory, where a diagnostic cast (stone model) is poured. The technician uses this cast to fabricate a custom impression tray, often made from acrylic resin, designed to fit the patient’s mouth closely. The custom tray allows the professional to control the impression material thickness, which is necessary for a highly accurate final impression. The final impression is taken using the custom tray and a high-precision material, such as polyvinyl siloxane or polyether, to capture the intricate details of the soft tissue and jaw contours. This detailed mold is the foundation upon which the final denture will be built, ensuring stability and a proper seal against the gums.
Defining the Fit and Aesthetics
Using the final cast, the laboratory creates a record base and wax rims. These temporary devices define the relationship between the upper and lower jaws. The wax rim simulates the size and position of the future teeth. The dental professional uses these rims to establish the patient’s correct vertical dimension of occlusion (VDO), which is the height of the lower face when the teeth are in contact.
The professional also records the centric relation (the most stable jaw position) and uses the wax rims to determine the midline, lip support, and the horizontal plane of the teeth. Next, the laboratory arranges the selected artificial teeth into the wax base to create a “wax try-in.” This setup is an exact replica of the planned final denture. It allows the patient and professional to assess the aesthetics, including the size, shape, and color of the teeth, before the permanent material is processed. Adjustments to the appearance and bite alignment are made at this stage, as it is much easier to modify the soft wax than the final hard acrylic.
Laboratory Fabrication and Finishing
Once the wax try-in is approved, the laboratory begins the conversion process to create the final acrylic denture. The stone cast with the approved wax denture is embedded in a metal container called a flask, using plaster or dental stone (flasking). This process creates a two-part mold that precisely holds the artificial teeth and captures the shape of the denture base.
Curing and Polishing
The flask is submerged in boiling water, which eliminates the wax, leaving a void that represents the future denture base. The artificial teeth remain fixed in the mold’s stone investment. After cleaning all wax residue, a separating medium is applied to the stone surfaces to prevent the new acrylic from bonding to the mold.
The liquid monomer and powder polymer are mixed to create the acrylic resin dough. This dough is packed into the mold’s void around the teeth under high pressure. The flask is then heated in a water bath (curing), which polymerizes the resin into a hard, durable plastic.
Finally, the cured denture is carefully removed from the flask (deflasked). The laboratory technician grinds away excess material and polishes the denture base to a smooth, high-shine finish.
Final Fitting and Ongoing Adjustments
The final step is the delivery appointment, where the finished acrylic denture is seated in the mouth. The dental professional checks the fit, comfort, and bite to ensure the appliance functions as intended. Minor adjustments are often required at this stage to eliminate any pressure points that could cause discomfort or sore spots on the gum tissue. The patient is also given instructions on how to properly clean and care for the new appliance.
Even with a perfect initial fit, the shape of the patient’s jaw ridges changes over time due to the natural process of bone resorption. This means the denture will eventually lose its snug adaptation, necessitating follow-up procedures. A relining procedure involves adding a new layer of material to the inner surface of the denture to improve the fit against the gums. Alternatively, a rebasing procedure replaces the entire acrylic base while keeping the original teeth.