Animals which eat only meat are called . Their teeth are adapted to their diet. They have , which are long and pointed to help them rip and tear meat. They also have which are useful for crushing and grinding bones. Herbivores are plant eaters. They have to cut off plants, and molars which chew the plants as the jaw moves from side to side. Human beings are : their teeth are adapted for eating both meat and plants. Our back teeth are called molars. They are for grinding and crushing; our front teeth are incisors for cutting food; and in between, we have canines for gripping and ripping. During our lifetime, we have two sets of teeth. The first set - the teeth - last until we are about five years old when they begin to drop out. They are replaced by permanent teeth. We need to look after these, because they are not replaced if they are damaged. In order to protect our teeth, we need to regularly - especiallly after meals; we should use toothpaste with in it; we should visit the regularly; and we should avoid eating too many sweet foods which attract the that cause tooth decay.