Deafness is a common disability affecting millions of people around the world. Sometimes it is temporary, sometimes permanent.
Temporary causes include noise-induced deafness, infection and a foreign body in the ear. Permanent causes include noise-induced hearing loss, inherited causes and old-age.
You might have spotted that noise-induced hearing loss appears in both lists. This is because initially it can be temporary but may become permanent if the noise is severe or prolonged. Many people have had the temporary deafness and tinnitus of the problem after being at a party and having people shout in their ear all night. Wearing a good pair of moulded earplugs from http://zenplugs.com/molded-earplugs can protect you against noise-induced hearing loss. Don't risk losing your hearing!
Infection can cause temporary deafness by preventing the normal movement of the eardrum. Blockage of the Eustachian tube which drains the middle ear leads to the buildup of fluid. Dead skin and wax can clog up the ear canal, also leading to deafness.
Wax can build up in the ear, causing temporary deafness. Incorrect use of an ear bud can cause this problem. Pushing it into the canal can move the wax back up towards the eardrum where it dries and cakes. Normally the ear canal is self clearing and does not need to be cleaned out. Earbuds should be used just to remove wax from around the opening of the ear.
Permanent hearing loss from old-age is impossible to avoid. Wearing hearing aids can help. It is worth getting the best ones you can afford because cheaper ones often amplify background noise as much as the sound you want to hear. This can make the situation worse.