Tooth eruption could additionally be altered by some environmental factors. When eruption is prematurely stopped, the tooth is said to be impacted. The most common reason for tooth impaction is lack of house within the mouth for the tooth.[70] Other causes may be tumors, cysts, trauma, and thickened bone or delicate tissue. Tooth ankylosis happens when the tooth has already erupted into the mouth however the cementum or dentin has fused with the alveolar bone. This could cause a person to retain their main tooth as a substitute of getting it changed by a permanent one. The first set of tooth