An analysis of the missing tooth positions in 151 non-syndromic tooth agenesis patients with PAX9 variants revealed that the maxillary second molar (84.11%) and mandibular second molar (84.11%) were the most affected tooth positions, followed by the maxillary first molar (74.83%), maxillary second premolar (64.24%), and mandibular central incisor (49.01%). This evidence concerns the gene PAX9 and tooth agenesis.