John W. McCartney

Segmental framework matrix: Master cast verification, corrected cast guide, and analog transfer template for implant-supported prostheses

A procedure is presented whereby a sectioned acrylic resin framework pattern for an implant-supported prosthesis is used for multiple purposes. It captures the three-dimensional spacial relationship of a dental implant. It acts as an analog transfer template, corrected cast guide, and a rigid scaffolding for the actual sculpting of the framework pattern.

Passive adaptation of the prosthesis-implant interface by soldering gold cylinders to the framework casting

Difficulties associated with accuracy of conventional long-span one-piece castings for fixed partial dentures are also observed in the fabrication of implant-supported prostheses. A technique is proposed whereby direct intraoral verification of cylinder-abutment relationship, master cast accuracy, possible corrected cast procedures, and soldering of gold cylinders to the framework ensure an accurate, passive adaptation of the prosthesis to all supporting implants.

Cantilever rests: an alternative to the unsupported distal cantilever of osseointegrated implant-supported prostheses for the edentulous mandible.

Mandibular prostheses supported by implants placed between the mandibular foramina restrict the length of the distally cantilevered components to minimize torque-related stress to the supporting implants. Additional posterior implants used as abutments with rigid attachments better distribute occlusal forces and reduce cantilever torque to the anterior implants. Because of the phenomenon of mandibular flexure, these posterior implants could be subjected to stress-induced microdamage to the bone-implant interface. The use of posterior abutments for support of the cantilever without connection reduces the potential hazard of stress-induced microdamage.

Osseointegrated implant-supported and magnetically retained ear prosthesis: A clinical report

Osseointegrated implants were placed in the temporal bone and were used to retain attachments for an ear prosthesis. A screw-retained magnetic alloy casting was used to retain an acrylic resin magnet keeper, to which a silicone ear prosthesis was attached. The keeper provided vertical support for the prosthesis and facilitated orientation for prosthesis insertion. Stability and retention were provided without the use of adhesives.

Motion vector analysis of an abutment for a distal-extension removable partial denture: A pilot study

An investigation was conducted on the effect of various rest-clasp designs on abutment tooth movement when a testing prosthesis was subjected to vertical loading of the bilateral distal-extension base. The results did not reveal statistically significant differences among the rest-clasp designs tested. Variations in rest placement and/or clasp design had an effect on the magnitude and direction of force transmission to, and resultant movement of, the abutment tooth. Less force to the abutment tooth was recorded when a mesial rest was used with the rest-clasp designs as compared to a distal rest. Force transmission to the abutment was found to be greater when the vertical load was applied to the denture base on the same side than when applied to the opposite side of the denture base.

Intraoral connection of individual abutment attachments for an osseointegrated implant-supported prosthesis

A technique is demonstrated for simultaneous verification of abutment replica positions and accurate adaptation of the prosthesis framework to the abutments. A separate procedure to verify abutment replica positions, as well as potential soldering of the framework for long-span castings, is avoided.

Inverted anatomic tracing: A guide to establishing orbital tissue contours for the oculofacial prosthesis

A technique is described to aid the maxillofacial prosthetic technician in contouring an oculofacial prosthesis. This technique should reduce clinical time and improve prosthesis results.

The orbital shell: An aid in positioning the ocular component and verifying margin contours for oculofacial prostheses

The correct location of the orientation (conversational gaze) of the ocular component is vital to esthetically pleasing oculofacial prostheses. This location should be verified before time and energy are spent on sculpturing the oculofacial prosthesis. A technique is described that uses a clear acrylic resin shell as a matrix and Play-doh material as a support medium to position and support the ocular component to verify the orientation. In addition, the thin acrylic resin shell can be used to refine border inaccuracies that may exist clinically.

The MGR clasp: An esthetic extracoronal retainer for maxillary canines

Summary The MGR clasp design provides an extracoronal retainer, in which reciprocation for a distolabial wrought-wire retentive arm is provided by a distal proximal plate and a “rod-like” minor connector that contacts a prepared mesial groove in the abutment. This MGR component permits the retentive clasp arm to be placed on the distolabial surface, thereby achieving improved esthetics (Fig. 7). Continuous positive reciprocation during retentive clasp arm flexure is provided.

Modification of angulated abutments to avoid unesthetic display of metal

A procedure is described whereby the facial margin of angulated abutments are repositioned to avoid unesthetic display of metal in the anterior maxilla. The procedure is not difficult and can make a considerable difference in the patients acceptance of the restoration.