The milk teeth will erupt between the age of about 6 months to 36 months. It has no significant differences between the sexes for the age of primary tooth eruption. The first teeth to erupt is the incisors, being more vertical than the permanent incisors, with a deeper incisal overbite. It is used for tearing the flesh. The next teeth to erupt is the first primary molar, the lower molar is slightly forward in relation to the upper molar. Following the molar, the canine teeth are the next milk teeth to erupt. The spaces exist between upper and lower teeth into which the opposing canine tooth interdigitates. It is the normal features of permanent dentition in the higher apes and in the human primary dentition are referred to as the anthropoid spaces. The last teeth to erupt in primary dentition is the second molars.
Development of the occlusion of the permanent dentition
In the permanent dentition, there are three stages. During this development, the lower canine tooth erupting at about 9 years of age and it comes between the first and second stage. In the first stage, the replacement of primary incisor teeth and the addition of four (first permanent molars to the dentition). The age ranges between 6 to 8 years. At the age of about 6 years the second primary molars will loss and the lower first permanent molar will move forward more than the upper first permanent molar. The first stage is completed by the end of 9th year and soon after this the permanent lower canine teeth erupt, replacing the corresponding primary teeth. In the second stage, the replacement of the primary molars and upper canine teeth by the premolars and the permanent upper canines and the addition of second molar teeth will take place in age range of 10 to 14 years. In stage three, the eruption of the third molars in early adult life completes the development of the occlusion of the permanent dentition. The age range for 3rd molar eruption is 18 to 25 years.
Advantages of knowing the development of teeth
- It is important to realize that the permanent dentition does not erupt into a static unchanging environment. During the 6 to 7 years over which most of the permanent occlusion develops, growth is continuing and maturation of function is occurring.
- The potential for change makes it desirable to have a knowledge of any changes which have occurred and are occurring during the development of a child's occlusion, so that any orthodontic treatment can be planned in the light of such knowledge.
The changes during development caused by growth, maturation of muscle function, alteration in habits or eruption of teeth, may cause changes in occlusal relationships.