The creation of custom-fitted dentures is a precise process involving dental professionals and specialized laboratory technicians. Dentures are removable prosthetic devices designed to replace missing teeth and surrounding tissues, restoring a patient’s ability to eat, speak, and smile. The manufacturing journey is a multi-step procedure that transforms initial oral measurements into a durable, functional appliance customized to the individual’s anatomical and aesthetic needs.
Initial Preparation and Impression Taking
The first step in fabricating a denture involves capturing an accurate replica of the patient’s mouth structure. This begins with a preliminary impression, often taken by the dentist using a stock tray and a material like alginate. This initial impression provides a diagnostic model used by the laboratory to construct a custom-fitting impression tray.
The custom tray is contoured to the patient’s anatomy, allowing the dental professional to take a second, more precise final impression. This impression uses a high-accuracy elastomeric material, such as vinyl polysiloxane (VPS), to record the fine details of the soft tissues and bony ridges. Capturing the full depth of the sulcus is important for maximizing the stability and retention of the finished denture. The resulting final impression is poured with dental stone, which hardens to create the master cast, a three-dimensional model upon which the denture will be built.
Designing the Denture Base and Teeth Arrangement
With the master casts prepared, the laboratory creates a temporary base and wax occlusion rims, also known as bite blocks. These rims allow the dentist to determine the correct vertical dimension—the distance between the upper and lower jaws—and establish the jaw relationship when biting.
The wax rims are marked with reference lines indicating the midline, smile line, and canine positions to guide the aesthetic placement of the prosthetic teeth. Once these measurements, known as the bite registration, are finalized, the master casts are mounted onto an articulator, a mechanical device that mimics jaw movements. The selected prosthetic teeth are then arranged in the wax base, creating a “wax try-in.” This try-in is approved by the patient for fit, comfort, and appearance before permanent manufacturing begins.
The Conversion Process
After the wax try-in is approved, the model is sent back to the lab for conversion into an acrylic denture. This begins with flasking, where the master cast and wax model are embedded in a metal container using dental plaster or stone. Once secured, the flask is heated in boiling water to melt and eliminate the wax, a process known as dewaxing.
The space left by the melted wax forms the mold for the permanent denture base. The dental technician applies a separating medium and then packs heat-cure acrylic resin into the mold space, surrounding the prosthetic teeth. The flask is closed under high pressure to ensure a dense, void-free material. The acrylic is then polymerized, or cured, by placing the flask in a controlled water bath, which permanently hardens the resin into the final denture base.
Final Finishing and Materials Overview
Following curing, the hardened denture is removed from the stone mold, a procedure known as deflasking. The technician begins finishing by removing excess acrylic material and smoothing all rough edges to eliminate potential irritation points.
The final step is polishing the denture to a high-shine finish, which aids hygiene by reducing plaque accumulation. The gum-colored base is typically polymethyl methacrylate (PMMA), an acrylic resin. Prosthetic teeth are made from acrylic resin, which bonds well, or from porcelain, which offers durability and a natural appearance. Partial dentures often integrate a chrome-cobalt alloy framework for added strength.