Molar-incisor hypoplasia in primary teeth

 # Molar-incisor hypoplasia in primary teeth at the occlusal level is due to developmental defect occurring during? 

A. Birth to 12 months 

B. 4th month intra-uterine to birth 

C. 22 months to 26 months 

D 24 months to 48 months 

The correct answer is B. 4th month intra uterine to birth.

# The most common dental complication of problems in utero is enamel hypoplasia. The deciduous teeth most effected by hypoplasia are maxillary incisors. They are the first teeth to start calcification, between the 3rd-4th months of intrauterine life. Amelogenesis of deciduous incisors is nearly completed at term birth. 

#Mineral is deposited in the matrix formed by ameloblastic activity from the fourth month of intrauterine life to form the enamel of the deciduous teeth (which is nothing but, 10-12 months in case of molars and incisors). Any severe illness in the mother is likely to be reflected in diminished amneloblastic activity.