Immediate dentures are dental prosthetics placed immediately following the extraction of remaining natural teeth. This procedure allows the patient to avoid being without teeth while waiting for the jawbone and gums to heal completely before a conventional denture can be made. They preserve the appearance and function of the mouth during the initial stages of healing. The materials used must accommodate the rapid and dramatic changes that occur in the mouth after surgery.
The Purpose and Function of Immediate Dentures
The primary function of an immediate denture is to provide continuous aesthetic and functional support from the moment teeth are removed. The appliance prevents the patient from being edentulous (toothless) during the initial healing period. The denture also acts as a surgical splint, helping to control post-extraction bleeding and shielding open wounds from the oral environment.
This prosthesis maintains the vertical dimension of the face and helps the surrounding muscles retain their tone, preventing the sunken facial appearance that often follows tooth loss. Unlike a conventional denture, which is fabricated after the gums and bone are fully healed, the immediate denture is custom-made based on molds taken before the extractions occur. Because the underlying tissues will inevitably shrink and change shape as they heal, the immediate denture is considered a temporary or transitional device.
Core Materials Used in Fabrication
The fundamental structure of an immediate denture is primarily composed of acrylic resin, a polymer material also known as polymethyl methacrylate (PMMA). The denture base, the gum-colored portion that rests on the soft tissue, is typically fabricated from heat-cured or cold-cured acrylic resin. This resin is tinted to match the patient’s natural gum color, providing the aesthetic foundation for the replacement teeth.
The denture teeth themselves are most often made from pre-fabricated acrylic resin or plastic. Acrylic teeth are preferred over older materials like porcelain because they are lighter, less brittle, and easier for the dentist to adjust for proper fit and bite alignment. In some cases, a heat-cured acrylic resin is used for the base to provide greater strength, while a cold-cured or auto-polymerizing resin may be used for minor, chairside modifications during the fitting process.
Material Properties Suitable for Immediate Placement
Acrylic resin is chosen because its inherent properties facilitate the unique demands of immediate placement. It is highly adaptable and can be easily trimmed, ground, and polished by the dentist using standard chairside instruments. This adjustability is necessary to relieve pressure points over surgical sites, which are subject to swelling immediately following the extractions.
The materials allow for rapid laboratory construction based on pre-extraction impressions, ensuring the denture is ready on the day of surgery. The base material must also be chemically compatible with various temporary reline materials that will be applied later, a property that acrylic resin reliably provides.
Material Changes During the Healing and Transition Phase
The most significant challenge is accommodating the rapid change in the underlying jaw structure. As the extraction sites heal, the alveolar bone naturally undergoes resorption, and the soft tissues shrink, causing the shape of the mouth to change drastically over the first few months. This tissue shrinkage causes the initial, well-fitting acrylic base to become loose and ill-fitting, creating spaces that can trap food and cause irritation.
To stabilize the fit and cushion the healing tissues, the dentist applies a temporary soft liner to the inner surface of the denture base. These materials are typically plasticized acrylic resins, such as poly-ethyl methacrylate (PEMA), or silicone elastomers. These soft reline materials are resilient and flexible, distributing the chewing forces more evenly and providing comfort to the tender gums.
The soft liner is a temporary measure, often lasting only a few weeks to a few months, because the plasticizers within the material leach out over time, causing it to lose its softness and eventually harden. Once the gums have fully healed (typically after six to twelve months), the immediate denture is either permanently relined with a hard acrylic material or replaced entirely with a new, conventional denture designed for long-term stability and function.