A machine designed to simulate the physical parameters of masticatory function was used to investigate the amount of wear produced on perspex plates opposing discs of porcelain which were glazed, unglazed or finished to varying stages of a polishing sequence recommended with a proprietary finishing kit. The perspex specimens were abraded, under water at 37 degrees C for a total of 800000 contacts using a contact time of 0.2 s, a sliding distance of 15 mm and a constant load of 0.19 N/mm2. Assessments of the wear of the perspex were based upon depth measurements of the wear track recorded on surfometric tracings. Further measurements of the cross-sectional area of the wear track were made using an image analysing computer. The investigation confirmed that the best finish and least abrasive surface was produced by glazing of porcelain. The finish produced by intermediate components of the proprietary finishing kit did not reduce the abrasiveness of the porcelain surface. It was necessary to complete the polishing sequence with diamond paste to achieve a surface which approached the wear characteristics of glazed porcelain. It is recommended that any adjusted porcelain restoration should be re-glazed or subjected to a finishing sequence which is followed through to a final stage of polishing with a diamond paste.

In this study, we evaluate coaxial electrospun nanofibers with gelatin in the shell and polyvinyl (PVA) in the core as a potential vascular material by determining fiber surface roughness, as well as human platelet deposition and activation under varying conditions. PVA scaffolds had the highest surface roughness (Ra = 65.5 ± 6.8 nm) but the lowest platelet deposition (34.2 ± 5.8 platelets) in comparison to gelatin nanofibers (Ra = 36.8 ± 3.0 nm & 168.9 ± 29.8 platelets) and coaxial nanofibers (1 Gel: 1 PVA coaxial – Ra = 24.0 ± 1.5 nm & 150.2 ± 17.4 platelets; 3 Gel: 1 PVA coaxial – Ra = 37.1 ± 2.8 nm & 167.8 ± 15.4 platelets). Therefore, the chemical structure of the gelatin nanofibers dominated surface roughness in platelet deposition. Due to their increased stiffness, the coaxial nanofibers had the highest platelet activation rate – rate of thrombin formation, in comparison to gelatin and PVA fibers. Our studies indicate that mechanical stiffness is a dominating factor for platelet deposition and activation, followed by biochemical moieties, and lastly surface roughness. Overall, these coaxial nanofibers are an appealing material for vascular applications by supporting cellular growth while minimizing platelet deposition and activation.

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Four hundred and fifty-five extracted mandibular incisor and 340 extracted mandibular premolar teeth were radiographed to assess the incidence of twin canals as visualized on radiographs taken in the mesio-distal direction. The ability to detect the presence of these twin canals by viewing radiographs taken in the standard bucco-lingual direction was then assessed. Using the guideline that 'disappearance or narrowing infers division' when viewing these radiographs resulted in a failure to diagnose one-third of the twin canals.