A case of delayed differentiation and/or calcification, that is, development, followed by accelerated growth of the maxillary second premolars is presented. This condition was accompanied by the congenital absence of mandibular second premolars even though maxillary and mandibular third molar germs were present. The case was followed over a five-year period. It seems that agenesis of any tooth might be found in conjunction with delay in development of any other tooth. Moreover, full development of a tooth germ (followed by an accelerated growth) as well as pathological changes may occur, despite an initial marked delay in tooth development.