David R. Cagna

An investigation of new metal framework design for metal ceramic restorations

STATEMENT OF PROBLEM Metal ceramic restorations have been implicated in the discoloration of associated gingival tissues. Attempts to remedy this by altering the design of the metal frameworks for such restorations may lead to unacceptable decreases in fracture resistance. PURPOSE This study evaluated a new metal framework design for metal-ceramic restorations. MATERIAL AND METHODS Twenty artificial crowns were fabricated with various degrees of facial metal reduction; 0, 1, 2, and 3 mm. The study was conducted in two parts. The first part evaluated changes in light transmission into adjacent root tissue. A light box was fabricated so sample crowns could be illuminated on a mounted natural tooth. The root of the tooth remained outside the light box, and the light transmitted through the crowns into root tissue was measured with a light meter. The second part of the study evaluated changes in fracture strength. The sample crowns were subjected to a vertical load until fracture with use of an Instron machine at a crosshead speed of 1 mm per minute. The load at fracture was recorded. RESULTS Results indicated a statistically significant increase in light transmission with 1 mm framework reduction or greater, and fracture strengths did not decrease with up to 1 mm of framework reduction. A 1 mm facial axial reduction of the metal framework may be indicated for anterior metal-ceramic restorations.

Subcrestal Implant Placement and Recontouring Soft Tissue Using the Erbium YAG Laser to Manage Restorative Space in Implant Overdentures: Recontouring Soft Tissue for Restorative Space

Subcrestal implant placement helps gain vertical restorative space at the location of the implants; however, this leads to the development of a tall mucosal cuff, necessitating the use of tall abutments. This article describes the technique of gaining restorative space by decreasing the height of the mucosal cuff with an Erbium YAG laser.

A Prosthesis Retention System for Full-Arch, Fixed, Implant-Supported Prosthesis: Retention System for Fixed Implant Prosthesis

Full-arch, fixed, implant-supported prostheses can be designed to be cement- or screw-retained. Both retention mechanisms have a few inherent disadvantages. A fixed attachment system has been introduced to circumvent the disadvantages of both screw and cement retention. This system eliminates the screw access holes and the use of cement. The number of intraoral procedures required is also reduced. The purpose of this article is to report a case using the Locator F-Tx Attachment System to facilitate fabrication of an esthetic, clinician-retrievable, full-arch implant-supported fixed dental prosthesis.

Modern application of the Skinner vertical movement stress director for distal extension partial removable dental prostheses: A clinical report

This article describes the prosthetic rehabilitation of a partially edentulous patient with a partial removable dental prosthesis (PRDP) designed to dissipate stress transmission to the denture foundation and abutment teeth. The Skinner stress director is considered an alternative design for managing partially edentulous patients.