Prosthetics
Dental Bridges are used to replace one or more missing teeth. Teeth on both sides of the space left by the missing teeth are prepared. A bridge is made up of abutments, the teeth that are prepped, and the missing, false teeth, which are called pontics. This procedure is used to replace one or more missing teeth and is cemented in. Most bridges are fixed, they cannot be removed. Fixed bridges cannot be taken out in the same way that partial dentures can. In areas of the mouth that are under less stress, such as the front teeth, a cantilever bridge may be used. Cantilever bridges or Maryland Bridges are used to replace anterior or front missing teeth, are minimally invasive but do have a reputation for failure. Bridges require commitment to serious oral hygiene and carry risk. The average life of bridges is similar to that of crowns which is nearly ten years.
A complete denture (also known as a full denture, false teeth or plate) is a removable appliance used when all teeth within a jaw have been lost and need to be prosthetically replaced. In contrast to a partial denture, a complete denture is constructed when there are no more teeth left in an arch, hence it is an exclusively tissue-supported prosthesis. A complete denture can be opposed by natural dentition, a partial or complete denture, fixed appliances or, sometimes, soft tissues. Many patients find the idea of wearing complete dentures very upsetting. Such psychological effects, together with the challenges that accompany successful prosthetic wear, can make acceptance of treatment difficult. It is, therefore, reasonable to consider different ways of transitioning into the edentate state in patients who have not yet lost all of their teeth but in which complete dentures will be required in the foreseeable future. Certain teeth can be retained in the short to medium-term with partial dentures provided in the interim so that the patient can become accustomed to denture wearing. Alternatively, if the former is not possible, consideration should be given to whether roots of teeth can be retained in strategic locations in the maxilla or mandible to help with the stability of the prostheses.
TRANSITIONAL PARTIAL DENTURES
Teeth that can be restored despite a poor long-term prognosis may be retained to transition the patient into the edentulous state via a series of transitional partial dentures. It is important that the patient can maintain good plaque control during this period, as progression of periodontal disease will lead to further destruction of bone that will later become the foundation for denture support. Complete dentures require some level of muscular control from the patient (e.g. lifting tongue to stabilize upper denture on biting) and this process of adaptation can last for several weeks or even months. As patients age, the process of learning and memorising new skills as well as neuromuscular control (i.e. controlling when and how much muscles contract) becomes more challenging. Hence transitional partial dentures can provide a practice period for the musculature, before complete dentures are provided.
OVERDENTURES
An overdenture is a prosthesis that fits over retained roots or implants in the jaws. Compared to conventional complete dentures, it provides a greater level of stability and support for the prosthesis. The mandibular (lower) jaw has a significantly less surface area compared to the maxillary (upper) jaw, hence retention of a lower prosthesis is much more reduced. Consequently, mandibular overdentures are much more commonly prescribed than maxillary ones, where the palate often provides enough support for the plate.
TOOTH SUPPORTED
Retaining two or three natural teeth as retained roots can greatly improve the retention and stability of a complete denture, especially if the roots are fitted with special precision attachments. The process involves decoronation (removing the crown of the tooth) and elective root canal treatment of the overdenture abutments. For matters of simplicity for endodontic treatment provision, single rooted anterior teeth are preferred, with the exception of lower incisors as they lack sufficient root surface area. If plaque control is satisfactory, tooth-supported overdentures can be considered as a long-term treatment option. Alternatively, if treatment fails, the roots can be extracted and the overdenture can easily be converted into a conventional complete denture.