In the meantime I've visited the dentist several times, but they didn't mention this. Neither did I, since it never actually bothered me - I thought it was natural. It even appeared quite suddenly, without any apparent reason. One moment I just started feeling something in the gum. It does not hurt and I have got used to the small sharp tip. A few days ago, though, I noticed that it was quite dark in colour (haven't looked at it in a while).
So my question would be - what is this small sharp thing in my gum? Tooth shard? Calculus? Would really like some help here, because I'm starting to get really worried.