Blue teeth?

No, no, not blue TEETH, blueTOOTH. A "bluetooth" device has nothing to do with either colors or dentures. Bluetooth is a way for electronic devices, such as cell phones, smart phones, tablets, and some computers and even televisions to communicate without wires. It only works over shorter distances (like from your purse or belt to your ear). Not all devices have Bluetooth capability, but if you have ever noticed someone seemingly talking to themselves as they walk along...and then see that they have some sort of big ear thingy on their ear, no wires.... then you are seeing someone using a Bluetooth headset to connect wirelessly to their smart phone or cell phone. You might also have a Bluetooth keyboard or mouse on your computer or laptop, because then the keyboard or mouse does not need any wires. To have two devices with Bluetooth talk to each other, you have to manually tell them to do it. This prevents someone nearby from latching onto your Bluetooth signal and, perhaps, listening in on the other half of a phone conversation.