Tetracycline deposition causes discoloration of either deciduous or permanent teeth.This happened when prophylactic or therapeutic regimens are given to a preganant female or postpartum in the infant.Tetracycline has a selective affinity towards deposition in bone and tooth through formation of a complex with calcium ions in the surface of the microcrystals of hydroxyapatite.What part of the tooth will be discolured will be decidied by the stage of tooth development at the time of drug adminstration.The discoloration depends on the dosage,length of the time over which the admistration occurred and the form of the tetracycline.In the deciduous dentition the period of mineralisation of the first millimeter of dentin nearest the dentinoenamel junction is four months in utero to three months postpartum for the maxillary and mandibular incisors and five months in utero to nine months postpartum for maxillary and mandibular canines.The period for permanent maxillary and mandibular incisors and canines is three to five months postpartum to seven years of age.
Clinical features:
The teeth affected appear to have a yellowish or brownish-gray discoloration which is most pronounced at the time of eruption of the teeth.This discoloration becomes more pronounced and becomes brownish after exposure to light.Tetracycline fluoresces under ultraviolet light.The dentin is usually more stained than the enamel.
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