Hi HaggisMaiden,
Liquid mercury is highly toxic so it's advisable not to handle it with bare hands etc. Most surgeries now use encapsulated amalgam where the alloy and mercury and compartmentalised within a plastic capsule which get mixed together in an amalgamation. If you've ever felt the finished mix ( through gloved hands ) you will know it feels warm. This means there is a chance of the mercury within the amalgam giving off vapour. However, this vapour is minimal, plus you wear a mask as well as gloves chairside. Also removing old amalgams causes them to warm up when using the high speed handpiece, so potentially causing mercury vapour. Again, you and the dentist are protected due to mask, gloves and the water used through the high speeds. Plus you are using your suction unit to remove as much debris as possible. From the patients point of view, they are only having necessary treatment so have minimal exposure. A point to note is that amalgams are not placed or replaced in pregnant women. This is to protect the unborn foetus from any mercury poisoning. That is not to say anyone would get poisoned from having an amalgam place/replaced. It is belt and braces formula I think.
As far as I know there are no known cases of dental nurses either being desperately ill or dying from mercury poisoning. It was Milliners, ie hat makers, that used mercury in felting hats that were poisoned over a century ago, hence the mad hatter in Alice in Wonderland. You may know all this already but we were discussing it with a new trainee the other day and it does make you feel better about handling the stuff when you go over all this.
All I can say is give mercury the respect it deserves as a poisonous substance and handle with care. 35 years as a dental nurse and I think I'm ok, ( although I go on a bit I know
)
If you want to scare yourself to death you could YouTube mercury poisoning. But honestly, in this day an age we would be stopped using it if it couldn't be managed.
Hope this helps, sorry for going on so long.