here goes…

okay, this is a tough one. but i will try.

firstly the concentration of HIV in saliva is really really low. so you cant actually get infected by saliva. as i have mentioned, there only those 4 fluids can actually cause infection.
for infection to occur,
a) the HIV has to be present in those fluids (duh)
b) it has to come out of the body
c) it has to “alive” – HIV CANNOT LIVE OUTSIDE YOUR BODY. it dies when it is exposed to air, water, whateve. it is like a parasite. it can only live in your body. however, i cannot tell how long long doesnt take for it to die as we dont really know. it depends on the quanity as well. the more the longer la.
d) it has to go into your body via open wounds, open cuts, blood stream, penis, vagina, anus. so there needs to be an entry point.

so in your case, say if you have a cut in your mouth and the blood somehow gets in there then yes, there is risk. risk as in there is a chance.
but also remember the blood is not that much and probably it has been exposed to air, water, saliva so probably, the virus could be dead. probably.

so it really depends. if there is wound in your mouth. but thus far there has been any cases like that. infection due to sharing o toothbrush. so no worries.

because blood is something which is visible. higly visible. so you can actually see if there’s blood on something. and usually if you wash it then its fine. cos as i said, HIV cannot live outside the body. but if you wanna be extra careful or whatever, then you can choose not to share those items which would include razor.

and there is clear difference between between HIV and AIDS. AIDS is wehn someone is terminally ill. HIV cause AIDS. HIV is the virus whereas AIDS is the syndrome/illness. i prefer to say syndrome cos i am super pc. so in your case, the persun is HIV positive not AIDS positive.

okay, i have a class. i need to go. if there are typos sorry. i have no time to re check. will add whatever if needed later.
hope this helps and sorry cfor the late reply.

thanks!

Please note that the last i checked — and i have no reason to believe anything has changed since then — doctors are actually obliged by the government to submit your name and ID should you test positive for HIV, which is why I would suggest going for PT’s anonymous screening if it’s available in your area.