Congenitally missing teeth is the developmental absence of one or more teeth excluding the third molars. It is one of the most common dental anomalies and has a negative impact on both looks and function. It rarely occurs in primary teeth (also known as deciduous, milk, first and baby teeth) and the most commonly affected are the adult second premolars and the upper lateral incisors.


Source: https://en.wikipedia.org/wiki/Hypodontia