Dentition is the type and arrangements of teeth in the oral cavity. In other words it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. The dentition in human can be clinically divided into three stages.
A. The Primary dentition consists of 20 teeth in all: ten upper and ten lower teeth. Primary teeth or milk teeth or deciduous teeth are called the first teeth of a child. They start appearing in the mouth at the age of 6 months and continue to do so till the age of 2.5 to 3 years and entirely replaced by about ages 12 - 13. There is no premolar in primary dentition.
Deciduous Dentition
B. The mixed dentition is composed of both primary and permanent teeth. It commences with the eruption of the first of the permanent tooth at about age six, and ends with the loss of the last of the deciduous tooth at about the age of 12-13 years.
C. Stage of Permanent dentition, lasting from 13 years onwards. During this stage only permanent teeth are present. There are 32 permanent and only 20 deciduous teeth. Therefore, 12 permanent teeth erupt in the oral cavity which does not have any deciduous predecessors. Deciduous molars are replaced by premolars in the permanent dentition.
Permanent Dentition
The teeth are arranged in two dental arches: 1. Maxillary or upper arch 2. Mandibular or lower arch. There are equal numbers of teeth in the upper arch and lower arch. The arrangement of teeth is symmetrical in the right and the left halves in each arch. Thus in each arch there is 10 deciduous teeth in deciduous dentition and 16 permanent teeth in permanent dentition. In other words, each of four quadrants of the jaws will have 5 deciduous teeth in primary dentition and 8 permanent teeth in secondary dentition. The teeth of one half of the jaws are exact mirror image of the other half.
Primary dentition- time of eruption
Time of eruption of Permanent tooth
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