Fracture resistance of cingulum rest seats in CAD-CAM tooth-colored crowns for removable partial denture abutments.

Statement Of Problem: The prevalent use of computer-aided design and computer-aided manufacturing (CAD-CAM) for tooth-colored ceramic materials has led to several case reports and retrospective clinical studies of surveyed crowns used to support removable partial dentures. How the specific contour of a cingulum rest seat affects the fracture resistance of these CAD-CAM tooth-colored materials is unknown.

Purpose: The purpose of this in vitro study was to compare the fracture resistance of monolithic CAD-CAM tooth-colored mandibular canine-surveyed ceramic crowns with cingulum rest seats of different designs.

An in vitro comparison of photogrammetric and conventional complete-arch implant impression techniques.

Statement Of Problem: Conventional impression techniques for recording the location and orientation of implant-supported, complete-arch prostheses are time consuming and prone to error. The direct optical recording of the location and orientation of implants, without the need for intermediate transfer steps, could reduce or eliminate those disadvantages.

Purpose: The objective of this study was to assess the feasibility of using a photogrammetric technique to record the location and orientation of multiple implants and to compare the results with those of a conventional complete-arch impression technique.

A segmented implant surgical guide connected with magnets.

The 2-piece surgical guide introduced in this article is designed for guiding implant placement in the edentulous arch. With the aid of embedded magnets, this guide can be easily and quickly assembled and disassembled during the surgical procedure without losing the predetermined guidance for the implant placement.

Freedom of rotation of selected overdenture attachments: an in vitro study.

Statement Of Problem: Attachments for mandibular overdentures may not allow for adequate freedom of rotation.

Purpose: The purpose of this study was to subject 3 commonly used stud types of resilient attachments to rotation and to measure and compare the degree of rotation that occurs before the attachments bind.

Material And Methods: Three stud attachments (ERA, Locator Extended Range, O-Ring System) with their corresponding metal housings were evaluated, first for a single implant system and secondly for a 2-attachment parallel implant system for the mandibular arch.

A comparison of the rigidity of five mandibular major connectors for partial removable dental prostheses via load deflection.

Statement Of Problem: The rigidity of the major connector for partial removable dental prostheses (PRDP) has not been well defined. There is little scientific evidence to support specific standards relative to the dimensions of a casting and their effect on long-term function of the PRDP or the supporting tissues.

Purpose: The purpose of this study was to compare in vitro the effects of load deflection of 5 clinically used mandibular major connector forms.

Managing the maxillary partially edentulous patient with extensive anterior tooth loss and advanced periodontal disease using a removable partial denture: a clinical report.

The treatment modality, a continuous occlusal rest removable partial denture, not only restored missing teeth but also stabilized the remaining dentition in a patient with advanced periodontal attachment loss. By engaging the guiding planes at the mesial surfaces of the abutments anteriorly and also the distal surfaces of the abutments posteriorly, the remaining teeth, with varying amounts of mobility, were splinted together by the framework. This conservative treatment option allows flexibility for easy repair during the life span of the prosthesis.

Laser welding of removable partial denture frameworks.

Purpose: To identify and measure distortions inherent in the casting process of a Class III mandibular cobalt-chromium (Co-Cr) framework to illustrate the problems faced by the laboratory technician and the clinician and to measure the changes that occur during the correction of the fit discrepancy using laser welding.

Materials And Methods: Five identical castings of a Co-Cr alloy partial denture casting were made and measured between 3 widely separated points using the x, y, and z adjustments of a Nikon Measurescope. The same measurements were made after each of the following clinical and laboratory procedures: sprue removal, sectioning of the casting into 3 parts through the posterior meshwork, fitting the segments to the master cast, picking up the segments using resin, and laser welding of the 3 segments.

Removable partial denture design using milled abutment surfaces and minimal soft tissue coverage for periodontally compromised teeth: a clinical report.

This clinical report describes the treatment of a partially edentulous patient with periodontally compromised teeth using a combination of single crowns and a removable partial denture (RPD). The RPD was designed to combine the benefits of milled surfaces and hygienic principles while allowing modification and addition of artificial teeth, should natural teeth be lost.

Lingual retention and the elimination of the visible clasp arm.

Unlabelled: The modern removable partial denture (RPD), in response to the increased esthetic demands of our patients, is no longer acceptable if it requires visible buccal and facial clasp arms for retention. By eliminating the bracing arm and having its functions taken by paralleled guide planes and precise, positive rests, the retentive element, a lingual circumferential wire clasp arm, will provide the same amount of retentive force as if it were placed on the buccal surface and will not be visible. Designs for the major connector either plate the lingual surface of the abutment or, as in a lingual bar, leave that surface open.

A clinical investigation of the fit of removable partial dental prosthesis clasp assemblies.

Statement Of Problem: Removable partial denture frameworks are complex castings fabricated from high-shrinkage alloys. This may result in difficulty in achieving accurate fit.

Purpose: The purpose of this study was to evaluate which component(s) of the clasp assembly contact the abutment tooth clinically.

The milled surface as a precision attachment.

The creation of paralleled, milled surfaces in natural or restored abutment teeth, coupled with removable partial denture castings that have optimal contact with these preparations, results in a path of insertion and removal that is controlled in a manner similar to one using conventional precision attachments. Because the milled surfaces are primarily extracoronal, little if any, additional tooth reduction is required for adequate mouth preparation. Avoiding additional tooth reduction minimizes later abutment fracture.

Clinical outcome of the altered cast impression procedure compared with use of a one-piece cast.

Statement Of The Problem: An altered cast impression procedure to improve the support of distal extension removable partial dentures is widely taught, but not often used in dental practice.

Purpose: The purpose of this study was to determine the efficacy of an altered cast compared to a one-piece cast with regard to base support, abutment health, and patient comfort over time.

Material And Methods: Seventy-two patients receiving a mandibular bilateral distal extension removable partial denture were assigned randomly for treatment using either a one-piece or an altered cast.

The conversion partial denture: a clinical report.

The treatment alternative described maximizes the benefit of remaining teeth while allowing simplified alteration of the prosthesis if abutments are lost during the life span of the removable partial denture (RPD). A conversion partial is an RPD whose tooth-frame assembly components are individually fabricated and then joined with an acrylic resin major connector. The conversion RPD optimizes retention and stabilization of a terminal dentition and can be easily converted to an immediate complete denture.

Posterior implants for distal extension removable prostheses: a retrospective study.

Common complaints associated with the Kennedy Class I (bilateral free end) and Class II (unilateral free end) removable partial denture situations are lack of stability, minimal retention, and unesthetic retentive clasping. Some of the same complaints have been reported for implant overdentures with only anterior implants. Starting in 1995, 10 of these patients were treated at the University of Washington with posterior osseointegrated implants to provide stability and/or retention of the removable prostheses, eliminating the need for clasps when possible.

The milled implant bar: an alternative to spark erosion.

Patients who cannot tolerate total coverage of the hard palate or whose maxillary arches are poorly formed, because of congenital, developmental or surgical defects, may be unable to wear a conventional complete denture. These patients can be successfully treated with implant-supported prostheses that cover only a minimal amount of palatal tissue. With spark-eroded castings, very precise restorations can be constructed to fit such implant supports.

Custom precision attachment housings for removable partial dentures.

Limited space for extracoronal attachments is a serious complication in the design and fabrication of a precision attachment removable partial denture. A custom metal-ceramic housing joined to the partial framework with laser welding offers strength and improved esthetics while requiring minimal space. This article presents the technical aspects of custom housing construction.