Wudhu

Food getting stuck in dental cavities

Q:

1. I have cavities in my tooth, and when I eat, food gets stuck. When I rinse my mouth or use miswak, it's still stuck. But when I brush my teeth, it easily comes out. Should I brush my teeth before I perform wudhu everytime I eat, or is it okay for the food to be stuck in the cavities?

2. Is it permissible to have dental fillings so that food doesn't get stuck, or is the filling regarded the same as stuck food? If it is permissible, is there any specific type which should be used as a filling? For example, the fillings come in gold, porcelain, a composite resin (tooth-colored fillings), and an amalgam (an alloy of mercury, silver, copper, tin and sometimes zinc).

3. Sometimes, the food eaten comes back to mouth unintentionally. When this happens, does wudhu break? What about fast?

Ingredients in make-up powders

Q: I want to ask a question about cosmetic ingredients mica and stearate acid which is used in face powders and blusher is it halal to use it? I read that mica is a kind of silicate or silicone which sticks to your hair and will not come out. It is not recommended because you cannot do wudhu. 

Person who has scabs and open wounds making wudhu

Q:

1. I have persistent acne on my scalp and pimples often pop and pus/blood comes out. If a pimple pops then scabs, are these scabs impure?

2. If I wash my head when it has many scabs on it does the water become impure? If one of these scabs falls off, do I have to purify the area?

3. I also have a persistent toe infection that also drains pus/blood on and off at random times. For nearly all my fardh prayers, the infection spot is bleeding/draining pus. My question is, if my toe is bleeding/draining pus and it's time for prayer, how to I wash the area? I mean if I wash it normally, then the water that runs over it (which will no doubt run over the rest of my toe as well) will be impure, making my entire toe impure. How should I deal with this? In fact, how should one deal with washing bleeding limbs for wudu in general? If one runs water over it, the water becomes impure and everywhere else the water touches becomes impure. Is this impurity disregarded during prayer?