Implant overdentures are an excellent treatment option for the edentulous patient
This type of prosthesis is indicated when patient demands cannot be met either through a fixed implant prosthesis or through a complete denture
Retention is obtained through use of attachments placed directly on implants or on bar superstructures.
Adequate cleaning and hygiene measures and maintenance of the removable denture and intraoral retention elements are crucial for long-term clinical success
Fixed versus removable prosthesis design
Most patients prefer fixed restoration designs to have the feel of 'natural teeth' and in most situations with low to moderate bone atrophy and when the patient is able to perform an adequate oral hygiene, fixed implant restorations will be a suitable and comfortable treatment option. In situations with considerable bone loss an implant-retained overdenture construction is usually the option of choice in order to restore the vertical dimension.
Given the extra cost associated with the fabrication of the superstructure, fixed implant-supported dentures are initially usually more expensive than implant-retained overdentures. However, fixed implant-supported dentures appear to have fewer ongoing routine maintenance requirements than implant-retained overdentures (these prostheses can be removed and the patient has to insert and remove them daily).
It can be questioned whether the maintenance costs and technical demands associated with an implant-supported overdenture are warranted when given the option of a fixed prosthesis. Adequate cleaning and hygiene measures and maintenance of the removable denture and intraoral retention elements are crucial for longterm clinical success. Therefore, some patient demands cannot be fully addressed with a fixed prosthesis, e.g. esthetic and functional concerns that are not reconcilable with provision and facilitation of adequate oral hygiene access.
Consequently the implant supported/retained overdenture offers expanded scope for recruiting implant therapy into the routine management of the edentulous patient.
Overdenture retention devices, overview
Implant overdenture attachment systems are comprised of two parts, one part connected to the implant/bar and the other within the prosthesis. The matrix is the receptacle component and a corresponding fit closely either mechanically or by friction
Ball anchors and locators are popular since they offer simple protocols and can be built into existing or new prostheses
Bar constructions offer design flexibility for different situations and optimal prosthetic teeth positioning
Bar constructions offer more retention and stability, but more prevalence for mucositis because of reduced cleaning access