Permanent tooth eruption is the process of tooth development which occurs over an approximate 7 year period, during which a child’s original baby teeth fall out and are replaced by the adult teeth. The primary (baby) teeth have usually emerged by the time a child is 3 years old, with 10 teeth residing in each jaw. During this time, these first teeth are acting as placeholders for the permanent teeth soon to come. Permanent teeth typically begin erupting around age 6, although they may appear earlier or later, usually in correlation with when the baby teeth came in. Most of the permanent teeth begin to erupt several weeks after the corresponding baby teeth fall out; however, while there are 20 baby teeth, ultimately 32 permanent teeth will emerge (16 in each jaw). Crowding of the permanent teeth occurs when the jaw does not have enough room to accommodate the incoming teeth. Crowding can be caused by: Early loss of baby teeth: When a baby tooth comes out too early, either from early childhood caries (baby bottle tooth decay), dental trauma (injury), or necessary extraction, the remaining adjacent teeth can shift into the space and cause the permanent tooth to be obstructed and erupt misaligned. Small jaw size: In some cases, the teeth are mismatched for the size of the patient’s jaw. The manner in which the teeth erupt is influenced greatly by heredity. Visiting your dentist regularly will help keep your child’s permanent teeth healthy and free of cavities .