RESUMO
@#Objective To measure the quality of manual wheelchairs made in China. Methods 20 wheelchairs was tested with ISO 7176-8, focused on the static strength, impact strength and fatigue strength. Results 8 (40%) wheelchairs passed the test. Conclusion The fatigue strength is the key factor of the wheelchair quality.
RESUMO
Objective To measure the quality of manual wheelchairs made in China. Methods 20 wheelchairs was tested with ISO 7176-8, focused on the static strength, impact strength and fatigue strength. Results 8 (40%) wheelchairs passed the test. Conclusion The fa-tigue strength is the key factor of the wheelchair quality.
RESUMO
Current dental restorations present a relatively weak resistance to fracture. Owing to their unique mechanical properties, fibre-reinforced polymers are now being considered. Unidirectional or woven continuous fibres, made of glass, polyethylene, carbon or Kevlar, have been evaluated. This study focused on the use of glass fibre knitted fabrics to reinforce acrylate resins, in order to investigate the possibility to construct single crowns as well as three unit bridges. Some points affecting the final composite system were tested: 1) static strength, with focus on the stress transfer under a occlusal contact point; 2) modelling of a three unit bridge; 3) fatigue strength as a posterior three unit bridge material. The study demonstrated that knitted fabric reinforcements are showing an interesting compromise between stiffness, static strength for single crown. For three unit bridge applications in the posterior arch, however, knitted glass fabric reinforcements were not strong enough in fatigue. An additional reinforcement in the posterior arch fixed partial denture design was recommended.