AIMS To establish the minimum dimensions for a non-precious cast metal occlusal rest by using mathematical analysis. An occlusal rest in a removable partial denture (RPD) provides vertical support and allows occlusal forces to be transmitted through the long axis of the abutment tooth. METHODS The stress status of an occlusal rest in a posterior tooth-bounded RPD resembles that of a cantileve...

Orthodontic mechanotherapy encompasses the use of several archwires during speci c stages of treatment. Metallic orthodontic appliances consist of bands, arch wires, ligature wires, hooks, tubes, brackets, and springs are daily used in orthodontic practices for the correction of malocclusions in patients ( Oh et al. , 2004 ; Verstrynge et al. , 2006 ; Sabane et al. , 2009 ). One of the most im...

This paper was aimed to address the modeling and optimization of factors affecting the corrosive wear of low alloy and high carbon chromium steel balls. Response surface methodology, central composite design (CCD) was employed to assess the main and interactive effects of the parameters and also to model and minimize the corrosive wear of the steels. The second-order polynomial regression model...

We retrieved 159 femoral heads at revision surgery to determine changes in surface configuration. Macroscopic wear of the head was observed in three bipolar hip prostheses as a result of three-body wear. There was a considerable change in surface roughness in the internal articulation of bipolar hip prostheses. Roughness in alumina heads was almost the same as that in new cobalt-chromium heads....

Objective: To evaluate marginal discrepancies between cast implant superstructure and EDM processed implant structure. Materials and methods: For the purpose of this study, an experimental model was prepared on which nine cast implant superstructure in nickel-chromium were fabricated which was then subjected to EDM processing. One-screw test was used to verify fit of superstructure both preand ...

a rahalt-chromium (Co-Cr) alloy using a centrifugal shooting type polishing machine. In tha present work, we examined the effects of the texture of polishing particle and polishing time on the surface roughness of Co-Cr alloy cast specimens. Nine differcnt textures of polishing par'ticle were investigated wiLh respect to core material and paTticle abrasiveness: three (lifferent elastic body cer...

This study aimed at comparing amounts of nickel (Ni) and chromium (Cr) released from brackets from different manufacturers in simulated oral environments. 280 brackets were equally divided into 7 groups according to manufacturer. 6 groups of brackets were stainless steel, and 1 group of brackets was made of a cobalt-chromium alloy with low Ni content (0.5%). International standard ISO 10271/200...

Restoration of esthetics is an important factor to consider in the fabrication of a removable partial denture (RPD) . 1 Several types of polymers and metal alloys have been used in RPD construction. Frequently, RPD clasps made from the same alloy as the metal framework. The most common alloys used for clasps are cobalt-chromium (Co-Cr) alloy and gold and titanium alloys, although these may be u...

Spark plasma sintering has been used for the first time to prepare the ASTM F75 cobalt-chromium-molybdenum (Co-Cr-Mo) orthopaedic alloy composition using nanopowders. In the preliminary work presented in this report, the effect of processing variables on the structural features of the alloy (phases present, grain size and microstructure) has been investigated. Specimens of greater than 99.5 per...