Fabrication of full coverage restorations for existing removable partial dentures

Fabricating a crown under an existing removable partial denture with impression scanning and CAD-CAM technology

Retrofitting a new crown to an existing removable partial denture (RPD) is a challenging procedure. Recently, intraoral scanners (IOSs) have been successfully used to solve this issue. However, purchase of IOSs is necessary, and most clinicians still use the conventional impression technique. This article describes a combined conventional and digital approach to fabricating a new crown under an RPD without an IOS.

Fabricating abutment crowns for existing removable partial dentures using custom resin clasp analogs

A universal approach for fabricating abutment crowns for existing removable partial dentures is described. A replica (analog) of the clasp assembly is generated and transferred to a traditional working cast, which includes the abutment die. The analog is incorporated into the working cast as a removable component to allow the formation of the crown contours. The article reviews in detail the procedures required to transfer accurately all the essential components and information from the mouth to the working cast while allowing the patient uninterrupted use of the removable partial denture. Prestabilizing the removable partial denture, creating the analog impression, avoiding errors due to soft tissue components, forming a precise analog base, selecting materials, generating a rigid resin analog, and prescribing a path of insertion and withdrawal to the analog are described. The method replicates all types of clasps and can generate all types of fixed prosthodontic retainers to function harmoniously with the existing partial denture.

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.

An indirect procedure for making a crown under an existing partial denture

Direct procedures to make a crown under an existing partial denture are inconvenient for the patient. A process is described that uses an irreversible impression of both the crown preparation and the removable prosthesis to fabricate a crown indirectly. The process is efficient and inexpensive.

A review of techniques of crown fabrication for existing removable partial dentures

Fourteen methods for making a crown to fit an RPD have been described. The techniques have been briefly reviewed and classified to indicate whether crown pattern construction is direct, direct-indirect, or indirect, and whether the RPD is needed in the laboratory phase. The choice of a technique appears to be a matter of personal preference for the dentist.