DENTAL PROSTHODONTICS

 

Fixed dentures

 

Fixed denture is a dental restoration used to replace missing teeth, reconstructing their function and esthetic. The process of preparation usually involves cutting the tooth with special dental burs, to make space for the planned restorative materials, and to remove any dental decay or portions of the tooth that are structurally unsound.

Types of fixed dentures may vary, such as crown, bridge and implant supported fixed denture. When a single tooth requires a prosthetic crown, it will rest upon prepared tooth structure that was originally supporting the crown of the natural tooth. However, the bridge is joining permanently adjacent teeth or dental implants, restoring more teeth than there are root structures or implants to support. In the cases when the tooth structure has been widely damaged, it has to be enforced by intraradicular core.
Different materials are used to fabricate fixed dentures. Traditional metallic construction covered by ceramic is still widely accepted. Modern dentistry has developed many new materials with excelent esthetic characteristics, such as zirconium-ceramic or full-ceramic.

During the period of denture production, the temporary crowns and bridges cover and protect the teeth enabling mastication and fonation. The temporary fixed dentures are produced in resin or composite and have the same function as the future definitive restorations.

 

Removable dentures

 

Removable denture is a prosthetic device constructed to replace missing teeth and is supported by surrounding soft and hard tissues of the oral cavity. There are two main categories of dentures depending on the number of teeth; partial and complete removable denture.
Complete dentures or full dentures are worn by patients who are missing all of the teeth in a single arch (upper or lower). Mostly are fabricated of a tissue shaded powder acrylic (resin) for the tissue shaded aspect, and acrylic or ceramic teeth available in different shapes and colors. Insertion of 2-4 implants serves as anchorage to improve denture retention and stability in the mouth, especially of the lower dentures.

Partial denture is for a partially edentulous patient who desires to have replacement teeth but cannot have a bridge (fixed partial denture) for any number of reasons (lack of posterior teeth to serve as support for a bridge, periodontaly compromised teeth, financial limitations). A removable partial denture can be made from a combination of acrylic with metallic framework, usually made of cast metal (chrome cobalt alloy). These metallic dentures or cast partial dentures are much superior to the regular acrylic dentures. Partial dentures use a variety of mechanisms to stay in place, like metallic clasps which hold on to the remaining teeth. Dental precision attachments offer the esthetic alternative to keep dentures in place. They consist of two parts that referred as the 'male' part that is fixed to a crown and a 'female' part which holds the partial denture.