Systemic (chronological) enamel defects

Date: 2015-10-07; view: 547.

Enamel formation in utero may be affected by a wide range of maternal and fetal conditions. These will include endocrine disturbances (hypoparathyroidism), infections (rubella), drugs (thalidomide), nutritional deficiencies, and haematological and metabolic disorders (Rhesus incompatibility). In such cases, the enamel covering the incisal portions of the crowns of the primary incisors will typically be affected. Similar changes may be seen in pre-term, low birth weight, infants. It is not yet clear whether this is associated with the use of intubation for these children in the neonatal period although the latter has been identified as a local cause affecting forming incisors only. When there is a systemic upset or marked physiological changes occur at birth or in the neonatal period, corresponding enamel defects may be seen in the primary dentition. Illness in the neonatal period may also affect the tips of the first permanent molars as these commence development after the birth. Enamel defects may also arise as a result of acute or chronic childhood illnesses. This will include hypothyroidism and hypoparathyroidism, chronic renal disease, and gastrointestinal disorders producing malabsorption, such as celiac disease. The use of tetracycline during pregnancy and childhood is to be avoided because of deposition of the tetracycline in developing dentalmatrices, producing a distinctive blue/grey discolouration of the teeth, sometimes in a chronologically banded distribution. In the past, exanthematous fevers caused by measles and other infections were associated with a disturbance of normal enamel formation and a corresponding chronological hypoplasia affecting the crowns of developing teeth. Modern medical care has now made this uncommon, unless such changes may occur in the case of babies and infants who develop pneumonia.