Influence of remaining coronal structure and finish line on the fracture strength of roots restored with metallic posts

The purpose of this study was to evaluate the fracture strength of roots that were prosthetically restored with metallic posts with or without any remaining coronal structure and with different finish lines. Sixty bovine incisors were sectioned below the cementoenamel junction, endodontically treated, and randomly divided into six experimental groups (n = 10) containing teeth with or without any remaining coronal structure, and with a beveled shoulder, a bevel, or a shoulder finish line design. The metallic posts were luted with dual-cured resin cement. The cores were made with composite resin, and metal crowns were cemented with zinc phosphate cement. The specimens were subjected to a tangential compressive load (135 degrees angle) at a crosshead speed of 0.5 mm/min until failure, using a universal testing machine. The fracture strength data were analyzed using the ANOVA and LSMeans (least square means) tests (alpha = 0.05). The data indicated that the teeth with 2 mm of remaining coronal structure showed the highest fracture strength values when compared with the teeth without any remaining structure (p < 0.05). As to the different finish line designs, the highest fracture strength values were obtained for the beveled shoulder, followed by the bevel and then by the shoulder designs (p < 0.05). It may be concluded that, to increase fracture strength, a beveled shoulder and 2 mm of remaining coronal structure are the ideal conditions.25434535

Influence of remaining coronal structure and of the marginal design on the fracture strength of roots restored with cast post and core

Objective. The purpose of this study was to evaluate the fracture strength of roots that were prosthetically restored with cast post and core with or without any remaining coronal structure and with different finish lines. Materials and methods. Sixty bovine incisors were sectioned below the cementoenamel junction, endodontically treated and randomly divided into six experimental groups (n = 10) containing teeth with or without any remaining coronal structure and with a beveled shoulder, a chanfered or a shoulder finish line design. The cast post and core were luted with dual-cured resin cement. The metal crowns were cemented with zinc phosphate cement. The specimens were subjected to a tangential compressive load (135 degrees angle) at a crosshead speed of 0.5 mm/min until failure, using a universal testing machine. The fracture strength data were analyzed using the ANOVA and LSMeans (least square means) tests (alpha = 0.05). Results. The data indicated that the teeth with 2 mm of remaining coronal structure showed the highest fracture strength values when compared with the teeth without any remaining structure (p < 0.05). As to the different finish line designs, the highest fracture strength values were obtained for the beveled shoulder, followed by the chanfered and then by the shoulder designs (p < 0.05). Conclusions. It may be concluded that, to increase fracture strength, a beveled shoulder and 2 mm of remaining coronal structure are the ideal conditions.71127828

Eosinophilia and symptomatic pulmonary amyloidosis

The case of a man with progressive breathlessness and pulmonary infiltration caused by AL amyloidosis associated with multiple myeloma is presented. There was a marked peripheral eosinophilia, which has not previously been described with amyloidosis