Restoring the Edentulous Maxilla Using an Implant‐Supported, Matrix‐Assisted Secondary Casting

Abstract

The selection of appropriate implant treatment modalities for the edentulous maxillary arch is complex. Although many patients are candidates for an implant-supported removable prosthesis, two major considerations affecting choice of treatment type are the amount of residual alveolar bone and soft tissue, and cost. A technique is described that employs a cast milled primary bar and a secondary casting constructed using a vacuum-formed 0.040-in plastic matrix. The secondary casting is intimately adapted to the primary bar and incorporates the retentive elements within it. The resulting prosthesis is less expensive than comparable designs, and retentive elements are easily replaceable. The technique is adaptable to most implant systems. The matrix-assisted secondary casting technique provides a design that is esthetic and hygienic. The prosthesis may also be easier to insert and remove than implant-supported removable prostheses that use plunger- or latch-type retention.

The implant-supported milled bar overdenture: A literature review

“…The suprastructure is recommended to be precisely and rigidly adjusted to the milled bar and made of the same alloy. Otherwise, the wearing away of the area between the suprastructure and the milled bar can be accelerated, and the presence of different metals give rise to galvanism phenomena (4).Clinical and laboratory processes involved in the making of the implant supported milled bar overdenture are similar to those needed to make the hybrid fixed removable overdenture, as originally designed by Dr. Branemark. The fine techniques used with traditional removable overdentures allow the making of this type of prostheses without having to resort to expensive machinery, offering high quality at a low cost, as compared to CAD/CAM or spark-erosionsystems (1,3,14).…”

“…The emerging of screws fixing the bar to implants in its vestibular side does not affect the aesthetics of the overdenture (as it happens with screwed prostheses) and the wrong position of some of the implants is not such a serious problem. Besides, the prosthesis can be removed at night to solve bruxism problems (1,2,4,7,9,16). Implant supported milled bar overdentures make it easier to replace the lack of tissues and to provide hygiene care in patients who have suffered the surgical ablation of maxillary tumours or present genetic problems causing lack of one or several teeth or the underdevelopment of dental crowns.…”

“…When the implants are placed on the anterior area of the first premolar teeth, the bar presents cantilevers towards the distal teeth which improve overdenture stability. The extension of the cantilevers will never overcome the anterior-posterior distance between the middle and distal implant by 1.5 times (2,4,8,10).…”

“…Besides, this overdenture includes fastenings which minimize the overdenture movement along its path of insertion. (1)(2)(3)(4)(5)(7)(8)(9)(10). Fixed porcelain prostheses are recommended in clinical cases where soft tissues and alveolar bones are intact -only lost teeth are replaced-.…”

“…Fixed porcelain prostheses are recommended in clinical cases where soft tissues and alveolar bones are intact -only lost teeth are replaced-. Hybrid prostheses and implant supported milled bars overdentures make it easier to obtain better aesthetic results in clinical cases where there have been losses of hard and soft tissues (2,4,7).…”