objectives: this study aimed to assess the effect of re-etching of desensitized dentin for five and 10 seconds on marginal microleakage of composite restorations. materials and methods: class v cavities (4x2x2mm) were prepared on the buccal surfaces of 64 third molars and randomly divided into four groups of 16. in the control group, single bond (sb) adhesive was applied after etching. in bb+sb...

In the present work, fat, skin, liver and muscle samples from Leptonychotes weddellii (Weddell seal, n=2 individuals), Lobodon carcinophagus (crabeater seal, n=2), Arctocephalus gazella (Antarctic fur seal, n=3) and Mirounga leonina (southern elephant seal, n=1) were collected from King George Island, Antarctica, and analysed for POPs (PCBs, organochlorine pesticides and PBDEs) and stable isoto...

introduction: the effect of apical patency on apical seal is very important in canal preparation. the effect of apical patency on seal of this area was evaluated in this study. methods and materials: in this experimental in vitro study, 90 single rooted mature intact human teeth were cut at cej and were divided in two test groups with 40 each and two control groups with 5 each. canal preparatio...

An elastomeric seal may leak by elastic deformation without any material damage. We describe elastic leak using a theoretical model, and watch a seal deform and leak using a transparent experimental setup. The elastomer seals the fluid by forming contact with surroundinghardmaterials. As the fluid pressure increases, the contact stress also increases but not as much. When the fluid pressure sur...