mouth and dental disorders
Biology of the Teeth
Tooth eruption
There is a broad range of normal times for teeth to push through the gum tissue (erupt) into the mouth. For primary teeth, the central incisors are the first teeth to erupt, occurring at about 6 months of age. These are followed by the lateral incisors, first primary molars, canines, and, finally, second primary molars. By about 2½ years of age, all the primary teeth can usually be seen in the child's mouth. Each of these primary teeth will be pushed out by a permanent tooth, starting at about age 6. The permanent first (6-year) molars come into the mouth just behind the last primary molars and, therefore, do not replace any teeth. This lack of replacement is also true for the permanent second and third molars. The third molars (wisdom teeth) are the last permanent teeth to come in, typically between the ages of 17 and 21. is one that cannot erupt because of a lack of space or because of the position of the teeth. Most teeth that become Impacted Teeth are wisdom teeth. In rare cases, a child isbornwith a tooth (a natal tooth), or a baby tooth erupts in the mouth within a month of birth (a neonatal tooth). These teeth are usually primary lower incisors, but they may be extra (supernumerary) teeth. These teeth are removed only if they interfere with nursing or if they become exceedingly loose. In many children, the permanent lower incisors come in behind each other. Lack of space (due to crowding, rotated permanent teeth, or abnormalities in skeletal development) may be the problem, and early Dental Appliances (braces) may be necessary. Thumb or finger sucking may also affect the position of teeth, sometimes requiring early orthodontic therapy. 