This article is based on an original article in Swedish which can be found here

BACKGROUND

An implant-retained overdenture is a construction where implants are used to retain a removable denture. The treatment can be seen as a way to improve the retention of a complete denture or as an alternative to a fixed implant bridge primarily in cases of complete edentulism. Scientific documentation shows that comfort and chewing ability improve significantly with implant-supported overdentures compared to conventional dentures, especially in the mandible.

See the article: Toothlessness

In many countries, implant-retained overdentures are a common treatment. However, in Sweden, largely due to reimbursement from dental care support, a fixed implant bridge is a significantly more common therapy. The reimbursement from dental care support reduces the difference in patient fees between the two treatment forms in favor of the fixed construction.

The Mandible

An implant-retained overdenture in the mandible is often performed with support from two implants, preferably placed in the canine or lateral incisor position.

The Maxilla

In the maxilla, it is desirable to have four implants placed bilaterally, one in the canine or lateral incisor position and one in the area of the second premolar. If it is not possible to install two implants in the anterior region, one in, for example, region 11 or 21 is a great help for the stability and pressure distribution of the denture. Three implants evenly distributed across the jaw are therefore significantly better than just two bilaterally. Experience shows that it is easy for the denture not to retain well if there are only one or two implants. In such cases, it may be better to use high spacers that retain the denture. The spacer is then adjusted, and soft base material is added. This allows for some movement in the denture.

Implant-retained overdentures are significantly more common in the mandible than in the maxilla. Reasons may include that constructions in the maxilla are often more expensive for the patient due to the need for multiple implants, and the prognosis is generally worse than in the mandible. A complete denture in the maxilla often functions well, which reduces the need for an implant-retained overdenture.

Partial implant-retained overdentures in residual dentition are rare but can, in some cases, be a good therapy option. An indication is patients who have undergone partial jaw resection in connection with cancer treatment. In these cases, where underlying bone is often lacking, for example, in parts of the palate, a unilateral free-end denture is significantly stabilized with one or more implants that retain the denture base. This also reduces the load on both the residual dentition and the transplant. The same applies after reconstructive surgery in the mandible. If it is not possible to install enough implants for a bridge, one fixture can significantly stabilize a partial denture and act as a pressure distributor.

In the Swedish National Guidelines for adult dental care, it is assessed that the condition of complete edentulism, in one or both jaws, has a very significant impact on oral health. The procedure of implant-supported overdenture has received a recommendation of two in the maxilla and three in the mandible.

A fixed implant bridge has received a score of two for treatment in both the maxilla and mandible in cases of complete edentulism. A complete denture in the maxilla has a score of two, while treatment in the mandible has a score of four, indicating a greater need for retention-enhancing measures in cases of complete edentulism in the mandible than in the maxilla.

RETENTION ELEMENTS

There are various technical solutions for retaining the denture to the implants.

Here are some of the most common;