Dentition in children may be divided into 3 chronological stages — a) eruption of primary or deciduous teeth, b) exfoliation of these teeth, and c) eruption of permanent teeth, though the timings of these events are too variable to be useful for growth assessment.
Normal dentition in children: Important events in normal dentition include —
• Total numbers of deciduous and permanent teeth are 20 and 32 respectively. There are no deciduous premolars and third molars.
• Primary dentition in children begins at 5-8 months with eruption of lower central incisor (first deciduous teeth) and completes by 2-2.5 years with eruption of second molars. A baby has —6 primary teeth at one year and —12-16 teeth at 2 years.
• Exfoliation of deciduous teeth begins at —6 years, usually with loss of first molar. Delayed shedding of deciduous teeth may lead to dental malalignment.
• Permanent dentition in children begins —2-4 months after exfoliation of first deciduous tooth (usually first molar) and continues well beyond the childhood till eruption of third molars (wisdom teeth) at 17-23 years.
Abnormal dentition: Common developmental abnormalities in dentition include – Natal teeth are occasionally present at birth as supernumerary or prematurely erupted deciduous teeth. These teeth are usually harmless and should be extracted only if loose or interfere with feeding.
Delayed dentition in children i.e. no primary tooth till 12 months of age, may be due to —
a) familial tendency,
b) nutritional deficiency e.g. PEM or rickets,
c) local gingival disease e.g. gum fibrosis,
d) inherited defects of dentin e.g. osteogenesis imperfecta,
e) endocrinal disorders e.g. hypothyroidism or hypoparathyroidism.
Anodontia i.e. absolute non-eruption of teeth is seen in Ectodermal dysplasia.
Discolored teeth usually indicate tetracycline therapy in early dentition in children (yellow staining), malnutrition, prolonged illness (discrete pit lines) or poor oral hygiene.
Premature exfoliation of tooth is common in dental caries, trauma and gingivitis. Rarely, recurrent tooth loss may also indicate of histiocytosis or cyclic neutropenia.