Fabricating crowns to fit existing removable partial dentures: an illustration of two techniques

The prosthetic treatment of a structurally compromised abutment tooth supporting a removable partial denture may present a variety of restorative modalities. Ideally, a surveyed crown is made for the individual tooth, which is later followed by a new removable partial denture fit to the contours of the crown. Frequently, however, the removable partial denture is clinically acceptable, and remaking the prosthesis is not indicated. In these cases, the crown can be made to fit the existing removable partial denture. Fabricating crowns to fit existing removable partial dentures can be accomplished using a direct method, an indirect method, or combinations of these techniques. Direct techniques traditionally use acrylic resin and inlay wax intraorally to develop a custom pattern that captures the contours of the clasp assembly. Indirect techniques use a pick-up impression to allow the crown pattern to be waxed against the denture framework on a cast in the laboratory. Combination methods use either a direct-indirect or indirect-direct approach. The direct-indirect method develops the preliminary resin pattern directly on the tooth and finalizes the contours in wax on a master cast. The indirect-direct technique initiates a crown pattern on a die and completes it either intraorally or on the die after the intraoral refinements. This article reviews the literature for methods of fabricating surveyed crowns under existing removable partial dentures. Additionally, two cases are presented that illustrate an indirect and combination direct-indirect technique for making the restorations.