Reinforcement tooth pin

We often hear that someone from our friends or relatives have established "dental pin" or "tooth on the pin", and often themselves dentists is highly recommended restoration of teeth is on pins. With what is the need of such manipulations? Let's face it. Let's start with the fact that the pins have long been used in dentistry, even in ancient times primitive craftsmen, barbers and later tried to strengthen teeth in various ways, ranging from blades of grass and twigs and finishing later thread and wire.