You have to understand the person whos dreaming really well. It's basically impossible with other people, it can only be done about yourself. Different things mean different things to different people. I think the best way to interpret a dream is to sit down and write about it, everything that happened and if it held any similarities to your real life. However, writing isn't for everybody, and there are other methods.
I myself have always found interpreting dreams a challenge and sometimes I don't know their meanings until their meanings have come to pass already. I feel I am living a dream that I must interpret right now, for I am only in the initial part of that dream which I dreamt 5 years ago. Yet I alone can interpret it as only I can understand the symbols and the meaning are personal to each. For me a dream about loosing my teeth is just an unconscious way of reminding myself to keep good dental hygiene, while for others it might mean that you all the lies that you have told will soon be seen through and you will be left exposed. It all depends on the individual. Journal your dream and with time, or when you least expect it you will know what it meant, means or might mean. Good luck.