The face is big and small: if it is a baby, it is likely to be calcium deficiency; If you are a teenager, you should get used to chewing with one big tooth. The side that is often chewed with big teeth is often larger, while the side that is rarely used is smaller. Open your mouth in front of the mirror and carefully observe and compare the big teeth on both sides of the mandible. You will also find that the growth direction of the big teeth on both sides is slightly different. The commonly used big teeth grow vertically upward, while the seldom used big teeth are slightly inclined to the lingual side. As for the way to sleep, I still suggest sleeping peacefully, but don't get used to unilateral posture, which will form a flat head.