Vitamin A and its derivatives, retinoic acid, tretinoin and isotretinoin, are 
currently used in dermatological treatments. The administration of high doses of 
this vitamin provokes congenital malformations in mice: cleft palate, maxillary 
and mandibular hypoplasia and total or partial fusion of the maxillary incisors. 
This study compares the tooth germs of the first maxillary and mandibular molars 
of fetal mice submitted to isotretinoin during organogenesis. Twelve 60-day-old 
female Mus musculus were divided into two groups on the 7th day of pregnancy: 
treated group--1 mg isotretinoin per kg body weight, dissolved in vegetable oil, 
was administered from the 7th to the 13th day of pregnancy; control 
group--vegetable oil in equivalent volume was administered orally for the same 
period. On the 16th day of pregnancy, the females were sacrificed, the fetuses 
were removed and their heads amputated. After standard laboratory procedures, 
6-micron thick serial slices were stained with hematoxylin and eosin for optical 
microscopy examination. The results showed that both groups had closed palates 
with no reminiscence of epithelial cells; however, the first molar germs of the 
isotretinoin-treated animals showed delayed development compared to the control 
animals.