Orientation of retentive matrices on spherical attachments independent of implant parallelism.

Traditionally, it has been advocated that implants planned for use as overdenture abutments be placed parallel to each other to obtain predictable attachment retention and complete seating of the restoration and to prevent premature wear of components. However, it is often difficult or impossible to place implants parallel to each other, and patients with implants that have already been placed in a variety of positions frequently are referred to restorative dentists. This article describes a technique for the fabrication of a matrix-paralleling device as well as 2 of its uses. The device allows proper orientation of the retentive matrices to establish a common path of withdrawal for the prosthesis and all attachments. Provided that the matrices are parallel to each other, spherical overdenture attachments can be used even when the implants are not parallel.