Whatever it is doing, the drill makes the same sound. Even in the absence of a bit (a small piece of metal cutting), it sounds the same. This is just the sound of the gears turning. But when it does have a thorn, he USES it to cut off your teeth to rot. There are many different types of burs, and he often needs to change several times before he passes. After filling, he USES it to shape the teeth, so it looks natural and has a ridge and all. Otherwise it would be flat on top.
The smell is rotten - they have to clean up before they can fill their stomachs. In my opinion, it smells like burnt teeth. Sometimes composite materials have a slight smell, but nothing bad.
